CLINICAL ANESTHESIOLOGY
People always wanted to overcome the sufferings caused by pain. The history of civilization left numerous documented evidences of permanent search for ways and methods of anaesthesia. The first written mention of the pain relieving medicines was found in
However, until the eighteenth century there was no radical ways of pain relieving. At this time, because of the fundamental discoveries iatural sciences the preconditions of new medical possibilities appeared. In 1776 chemist Priestley synthesized nitrous oxide – an anaesthetic, which is still widely used in anaesthesiology. Another chemist, Davy, on April 9, 1779 for the first time tested the effect of nitrous oxide on himself. Later he wrote: “Nitrous oxide, along with other properties, has the ability to relieve pain and thus can be successfully used in surgical operations”. And only 25 years later, an English surgeon Hickman began to use the “laughing gas” in medical practice. However, this method of anaesthesia had not received adequate acceptance in
However, priority in the use of ether narcosis belongs to another American researcher – Morton. On October 16, 1846 at
Therefore, the 16th of October, 1846 is considered to be the birthday of anaesthesiology.
In few months enthusiastic followers of ether narcosis appeared in all civilized countries. At the beginning of February 1847 this type of narcosis was performed by professor F.I. Inozemtsev in
In the Crimean-Turkish war (1853 – 1856) our compatriot performed hundreds of successful ether anaesthesias during surgeries on gunshot injuries.
In 1937 Guedel determined the clinical stages of ether narcosis, which are still considered to be classic.
In 1847 a prominent scientist Simpson introduced into clinical practice another preparation for narcosis – chloroform.
Since that time anaesthesiology has begun its scientific development.
For 150 years of anaesthesiology history scientists proposed and implemented in clinical practice dozens of anaesthetic preparations, both inhalation and non-inhalation, as long as various types and methods of pain relief. This stimulated development of operative surgery and allowed various range of surgical interventions in all organs and systems of the body.
Anaesthesiology is a science that studies how to protect the organism from operating injuries. It improves the well-known and develops new methods of preparing patients for surgeries, providing anaesthesia, controlling the body functions during the operation and in postoperative period.
1.2. Preparing of the patients for the surgery
During the preoperative period an anaesthesiologist should evaluate the patient’s condition (main disease and comorbidities, degrees of their compensation), provide correction of health disorders, prevent complications that may occur during the operation, etc. In another words anaesthesiologist should create perfect conditions to perform anaesthesia with the largest adequacy and the least harm to the patient.
The tasks of an anaesthesiologist are:
1. Evaluation of somatic and mental condition of the patient:
– determine the severity of main disease, concerning operation, which is planned;
– identify comorbidities (of the cardiovascular, respiratory, digestive, nervous and endocrine systems, etc.);
– define the psychological and emotional state of the patient (his/her attitude to future operations, anaesthesia, etc.).
2. Preoperative preparation of the patients.
3. Determination of the anaesthetic risk level.
4. Choice of the best anaesthesia method.
5. Postoperative treatment.
In the preoperative period it is essential to clarify the nature of operation: planned, urgent or emergency:
a) in case of planned surgeries with decompensated comorbidities there should be an adequate therapy performed at first; If necessary ask other specialists to take part in the treatment;
b) if an operation is urgent the main vital parameters should be stabilized in short term, further correction should be made during the operation;
c) in case of emergency the patient is transferred to the operating room as soon as possible, as anaesthesia and surgery are critical factors in saving his/her life. Stabilization of vital functions is achieved on the operating table.
During the examination of the patient special attention should be paid to the condition of the central and peripheral nervous system (mental and emotional lability, sleep disorders, the presence of anxiety and fear, paresis and paralysis). Constitution of the body, anthropometric data (weight and height) should be determined. The attention is paid to the subcutaneous fat and its distribution, peripheral veins.
While examination should be assessed: the skin and its colour, temperature, humidity and turgor of tissues (particular attention is paid to the capillary refill – press the nail of the patient for 5 seconds and if the white spot after pressing will not disappear in 2 seconds microcirculation is violated); anatomical features of the upper respiratory tract: the width of mouth opening, the size of oral cavity, presence of dentures, caries teeth, type of bite, the size of the tongue, size of tonsils, size of the nasal passages; shape of the neck and its size, the size of the thyroid gland.
Reserves of respiratory system are determined by spirometry tests (breath-holding after maximal inspiration and expiration – tests of Stange and Hench). Normally they are 50 – 60 sec. and 35 – 45 sec., respectively. If necessary, more detailed study called spirography is made.
The breathing rate should be determined and the chest should be examined (palpation, percussion and auscultation).
While assessing the state of the cardiovascular system, it is necessary to auscultate the heart, measure blood pressure and evaluate the pulse. In case of cardiac rhythm disorders, it is necessary to measure pulse deficit (the difference between the heart rate and the pulse rate on the radial artery per minute). An electrocardiogram should be made in order to make a detailed study of the disorder.
Examination of the digestive system should start from the tongue, which gives information about the degree of organism dehydration (dry tongue, marked buds, available longitudinal grooves), the severity of stomach inflammation (the tongue is coated), convulsions in anamnesis (scars on the tongue from biting), manifestations of avitaminosis and fungal diseases (“geographic”, raspberry tongue). Also the inspection, palpation, percussion and auscultation of the abdomen should be made. Always check the symptoms of peritoneal irritation and muscular defence of the anterior abdominal wall. Ask the patient about the distension of the abdomen, nature, and frequency of defecations.
The urinary system should be assessed by palpation of the kidneys and lower abdomen (projection areas of the bladder), check of Pasternacki symptom. The frequency, volume and nature of urination, colour and odour of the urine should be determined. In urgent and emergency surgery with suspicion of renal insufficiency the bladder should be always catheterized in order to control the urination during surgery.
Don’t forget to assess the probability of thrombosis: identify peripheral veins of lower extremities, swelling and pain of the ankles. Laboratory tests and instrumental examinations are also very important. The required minimum of these examinations depends on the urgency of an operation.
In emergency surgery as soon as possible (often right during the operation) the following analyses are made:
1. Clinical blood test.
2. Clinical urine analysis.
3. Blood group and Rh identification
4. ECG .
5. Glucose control.
Urgent operational interventions allow to perform the listed above diagnostic minimum is necessary in the preoperative period and also require:
6. X-ray examination of the chest.
7. Examination of the patient by a therapist (paediatrician) or a required specialist.
In preparing patients for planned operational interventions the functions of other organs and systems are examined in a more detailed way:
8. Biochemical analysis of the blood (bilirubin, urea, creatinine, protein and its fractions, electrolytes, coagulogram, transaminase, cholinesterase, etc.).
9. Functional tests to determine the degree of compensation of the respiratory, cardiovascular, central nervous systems, organs of detoxification and secretion (according to the indications).
10. Special instrumental investigations (endoscopy, angiography, ultrasound examination, scanning, etc.).
After you found a disease, which requires preoperative correction, treat it together with other leading experts and a responsible doctor. Duration of the therapy is limited on the one hand, by the nature and degree of compensation of this disease, on the other hand – by emergency of planned surgery.
2. Preoperative preparation of the patients (premedication) is divided into previous and immediate.
Previous premedication is a treatment given to the patients hours before the surgery (usually in the evening before the invasive procedure). It includes therapy of different dysfunctions as well as sedative treatment.
One of the obligations of the anaesthesiologist is to provide psychological and emotional comfort to the patient before the surgery. To achieve this aim use the following:
– psychological effect of medical personnel – soothing, honest conversation of an anaesthesiologist with the patient, including explanation of the basic stages of future operation and anaesthesia, provides the sense of a confidence and develops belief in favourable outcome of the treatment;
– sedative and analgesic therapy (therapeutic doses of benzodiazepines and sleeping pills for example).
A full, deep sleep and psycho-emotional balance of the patients before the surgery are very important for prevention of undesirable reactions of the vegetative and endocrine systems. They allow to create the best background for the uncomplicated introduction and providing of anaesthesia with quick end of narcosis.
Preparation of the gastrointestinal tract includes one obligatory condition – “empty stomach” (in order to prevent aspiration of gastric contents into the lungs). The patients should:
– follow the light diet during 2 – 3 days before the operation;
– not to eat at least 6-8 hours before the surgery;
– take H2blockers (ranitidine, cimetidin, etc.) before an operation to reduce gastric juice production and decrease its acidity;
– undergo cleansing enemas (in the evening and in the morning before an operation, however not before all surgeries; this method plays an important role in detoxification of the organism and soon restoration of the intestinal peristalsis in the early postoperative period;
In cases of urgent surgical interventions stomach should be clean with inserted gastric probe 1 hour before the operation; give 200 mg of cimetidine solution intravenously and 15 – 20 min. before the anaesthetic introduction ask the patient to drink 15 ml of 0.3 M sodium citrate solution.
Those steps will minimize the risk of vomiting, regurgitation and aspiration of the gastric contents into the airways (one of the most common and severe complications of anaesthesia).
Immediate premedication in planned surgery is performed 30-40 minutes before the intervention. The classical scheme includes such medicines (given i/m):
a) peripheral M-cholinolytics (0.1% atropine sulphate solution or 0.1%, metacin solution, dose: 0.01 mg / kg);
b) antihistaminic drug (1% dimedrol solution or 2.5%, pipolfen solution, 1-2 ml of 2% suprastin solution);
c) narcotic analgesics (1ml of 2% promedol solution or morphine hydrochloride, dose: 0.4 mg / kg).
In urgent operations premedication medicines are often used intravenously (right before induction). If there are special indication you can include into the typical premedication other medicines, such as: tranquilizers (2-4 ml of 0.5% Diazepam solution, 0.25% droperidol solution, etc.), non-narcotic analgesics ( 2 ml of 50% analgin solution, 5 ml of baralginum solution, etc.), steroids (60-90 mg of prednisolone solution), etc.
You should avoid rapid intravenous administration of antihistamine preparations, tranquilizers and narcotic analgesics in patients with deficiency of circulating blood volume due to the high probability of hypotension!
With properly chosen and performed premedication the patient is calm and a bit sleepy before the operation and to the operating-room he/she is transported on a trolley.
3. Evaluate the anaesthetic risk before each surgery. In
I. Somatic condition of the patients:
1. The patients without organic pathology or with local disease without systemic disorders.
2. The patients with light or moderate systemic disorders associated or not associated with surgical pathology, which moderately violate general condition.
3. The patients with severe systemic disorders, associated or not associated with surgical pathology that significantly violate vital functions.
4. The patients with the most severe systemic disorders associated or not associated with surgical pathology, which are life-threatening.
5. The patients in critical condition who can die within 24 hours with or without the surgery.
II. The severity of operative intervention.
A. Small operations on the body surface and hollow organs (uncomplicated appendectomy and hernial plastic, haemorrhoidal surgeries, amputation of fingers, etc.).
B. Operations of average size (amputation of the limb segments, complicated appendectomy and hernial plastic, peripheral vascular surgery).
C. Large operations (radical operations on the organs of the chest and abdomen, enlarged limb amputations).
D. Operations on the heart and main vessels.
E. Emergency surgery.
For example: a young patient without comorbidities is prepared for planned biliary tract surgery (calculous cholecystitis). The degree of operational risk is 1C. However, biochemical examination has revealed high level of glucose, and diabetes mellitus was diagnosed. Thus the degree of operational risk is 2C. In case of emergency operations of the same patient, the risk degree will be 2CE.
Now ASA (American Society f Anaesthesiologists) classification is widely used.
The tasks of medical staff in preparing of the patient to the surgery are:
– to create best conditions for psychological comfort of the patient. The appearance of the medical personnel should reassure the patient. Neat uniforms, accurate fulfilment of various manipulations, calm voice, encouraging smile and soothing conversation of a nurse or doctor are very important for the patient and develop confidence in a successful outcome of the treatment;
– to monitor changes of the patient’s state (colour of the skin, consciousness, body temperature, character of the respiration, blood pressure and pulse, urination volume,etc.);
– to perform clearly, professionally and skilfully the necessary manipulations (getting of i/v access; taking of blood samples for laboratory tests; intravenous, intramuscular and subcutaneous injections; insertion of gastric and urinary probes, etc.);
– to follow the rules of asepsis and antisepsis in the department;
– to perform premedication in a ward or in the operating room.
Remember, that some medicines must not be mixed in one syringe, like narcotics and atropine. After effective premedication patients can feel sleepy, so as it was mentioned above they are transported on a trolley to the operating room (don’r forget to control their condition during the transportation).
1.3 Anaesthesia and its preparations.
Anaesthesia is a set of methods applied to patients during operations and painful manipulations in order to protect their life and health.
Anaesthesia includes the following components:
– drug-induced sleep;
– pain relieve;
– neuro-vegetative protection;
– muscle relaxation;
– adequate ventilation;
-optimal level of blood circulation;
– normalization of metabolic processes in tissues.
Narcosis (from ‘narkosis’ – get torpid) is the process of temporary reversible depression of the central nervous system caused by pharmacological agents.
Analgesia (from Greek ‘analgesio’ – no pain) – absence of pain sensitivity.
Anaesthesia (from Greek ‘anaestesio’ – loss of sensation) – a set of methods used to remove all kinds of sensitivity.
Anaesthetics – pharmacological agents, which eliminate sensitivity.
Anaesthetics can have general (agents for narcosis) or local action (medicines for regional anaesthesia).
Depending on the way of admission anaesthetics are divided into inhalational and non-inhalational (mostly intravenous).
During inhalation anaesthesia gases or vapour of anaesthetics enter the patient’s through the airways and lungs (anaesthesia machines are connected with the mask, endotracheal tube, tracheostomy tube, etc.) This type of anaesthesia is characterized by the simplicity of the method and high degree of control. The most common anaesthetics are: nitrous oxide, sevoflurane, isoflurane, xenon. Ether and phtorotan have now historical meaning.
Non-inhalational anaesthesia can be delivered through intramuscular injection, orally or per rectum, but the most common way is intravenous administration.
Those first ways are less popular in adult anaesthesiology, however still popular in paediatric anaesthesiology.
Characteristic feature of intravenous total anaesthesia is its difficult control: the anaesthesia becomes dependable on the biological transformation (neutralization and excretion) of anaesthetic in the body.
Intravenous anaesthetics include barbiturates (hexenal, thiopental sodium) sodium oxybate, propofol, ketamine, etc. In the past viadril, propanidid, altezin were also used. There are combined methods of general anaesthesia, like: neuroleptanalgesia, ataralgesia, central analgesia and others.
Unlike general anaesthesia (narcosis), during regional anaesthesia patients are conscious.
Depending on the site of local anaesthetic administration (dicaine, novocain, lidocaine, bupivacaine, etc.), regional anaesthesia is divided into:
topical (surface); infiltrative; plexus and single nerves blockades; neuroaxial blockades – epidural, spinal anaesthesia.
Inhalation anaesthesia implies respiratory introduction of anaesthetics into the body. It can be performed through open, semi-open, semi-closed and closed circuits.
In the open circuit the patients inhale and exhale into the atmosphere; in semi-open they inhale oxygen or oxygen-air mixture, and exhale into the atmosphere. In closed and semi-closed circuits the patients inhale oxygen only from gas cylinders, and exhale completely (in closed circuits) or partially (in semi-closed circuits) into the chemical absorber (absorbs carbon dioxide). Respiratory mixture with eliminated carbon dioxide can be used for breathing again.
1. Nitrous oxide ( N2O) is a gas stored in liquefied state under the pressure of 50 atmospheres in the cylinders of grey colour (in French-speaking countries, these tanks are painted blue!). From 1 kg of liquid N2O about 500 litres of colourless inflammable stable gas are formed. To prevent gas freezing at the outlet of the container it is necessary to use a special type of reductors (ribbed). Gas supply of the anaesthetic machine is performed through a high-pressure hose. Dosage control is made with special flow measurement devices (rotameters).
Nitrous oxide should be always combined with oxygen in the anaesthetic mix, otherwise patient can die; usually a ratio of 1:1, 2:1, 3:1 are used.
Note that false connection of nitrous oxide supply hose to the oxygen supply inlet is dangerous for the patient!
This gas does not cause unconsciousness, has a weak anaesthetic and mild analgesic (pain-relieving) properties. It is not toxic for the patient and it can be combined with other inhalation and intravenous anaesthetics.
Harmful effects of nitrous oxide are noticeable when its concentrations in the respiratory mixture is over 75 – 80% (in these cases, the oxygen content in the mixture is lower than 20%, which is life-threatening).
Nitrous oxide is used in combination with other anaesthetics to enhance their effects during various anaesthesias, in the form of oxide-oxygen mixture – for pain relief during attacks of angina pectoris, myocardial infarction, complicated and uncomplicated childbirth.
2. Anaesthetic ether was widely used in anaesthesiology for about 150 years. Although currently ether is not used it is a classic of anaesthesiology.
Ether is a colourless volatile liquid with a specific odour. It is produced in orange bottles of 100 and 150 ml. Boiling point of ether is 37°. It is explosive!
Ether is a potent anaesthetic, which causes unconsciousness, analgesia and muscle relaxation. It has sympathomimetic effects (causes tachycardia, increases blood pressure, stimulates the activity of the salivary and bronchial glands, increases level of sugar in the blood, stimulates the respiratory centre).
In toxic doses, ether depresses the activity of the heart, liver and kidneys. It irritates the respiratory tract. Therefore, rapid increase of its concentration in the breathing mix can cause laryngeal or bronchial spasm.
Ether is an universal anaesthetic. It can be used in open, semi-open, semi-closed and closed circuits, in combination with other anaesthetics, during mask and intubation anaesthesia. Ether became popular as an anaesthetic because of its large therapeutic range and safety.
Ether as an anaesthetic is contra-indicated for patients with hypertension, diabetes mellitus, acute and chronic inflammation of the respiratory system. During ether narcosis, it is strongly contraindicated to use an open flame and it is dangerous to use diathermy!
During the surgery we usually evaluate the course of general anaesthesia according to the classic scheme of 4 ether narcosis stages.
Clinical course of ether narcosis (by Guedel).
I. Analgesia stage lasts from the start of vapour inhalation up to the loss of consciousness. It is characterized by the gradual loss of pain sensitivity (temperature and tactile are preserved) and depression of consciousness. During this stage you can do short-time surgery and painful manipulations.
II. Excitement stage. The patient loses consciousness. Motor and verbal excitement appear. Skin is hyperaemic, breathing is deep and noisy, the teeth are clenched, the eyeballs make floating movements, the pupils are dilated, all kinds of reflexes are increased. Blood pressure is increased, as well as heart rate; even ventricular fibrillation can occur.
During this stage various surgical interventions and manipulations are contraindicated! Just control the vital parameters and wait.
With the deepening of narcosis exciting symptoms fade, cross-striated muscles relax and breathing normalizes.
III. Surgical stage (stage “of narcotic sleep”) is divided into three levels:
III.1. It is characterized by quiet sleep, deep and rhythmic breathing. The pupils are narrow, their reaction to light is preserved, the eyeballs are “floating.” Ciliary, swallowing reflexes and reaction to weak pain stimuli disappear.
III.2. Corneal reflex is absent, the eyeballs are fixed in the central position, the pupils are narrow, and do not react to the light, breathing is rhythmic, blood pressure and heart rate are stable. The majority of surgical interventions are performed during this stage.
III.3. It is characterized by progressive depression of reflexes and vital functions. There may be signs of toxic ether effects: the dilated pupils, lack photoreaction, depression of respiration (with predominant diaphragmatic type of breathing) and cardiovascular activity, total lack of reaction to painful stimulation.
IV. Agonal stage is extremely dangerous, so you never intentionally deepen anaesthesia this much! In case of ether overdose there is a progressive depression of respiration and cardiac activity followed by cardiac arrest.
Pre-agonal signs of ether overdose: clammy cold sweat, grey skin colour, the sphincter relaxation and spontaneous urination and defecation.
During the recovering of the patient the same stages are observed, however in reverse order.
3. Fluothane (halothane) was widely used at the end of the 20th century, hoqever now its not popular. It was discovered by Raventos in 1956. It is a clear liquid with a sweet odour, not explosive. It is produced in bottles dark glass (capacity 50, 150, 250 ml).
Fluothane is characterized by severe anaesthetic and weak analgesic effect. It depresses the secretion of the salivary and the bronchial glands, extends the bronchi. The drug depresses the larynx and throat reflexes, the respiratory centre and relaxes the cross – striated muscles. It also causes myocardial depression.
Fluothane has a short therapeutic range, its overdose is characterised by hypotension and bradycardia.
During fluothane narcosis it is contraindicated to use sympathomimetics! Fluothane increases catecholamine sensitivity of the myocardium. Adrenaline, noradrenaline and other drugs of this group during fluothane anaesthesia can cause myocardial fibrillation, followed by cardiac arrest.
For the narcosis fluothane should be filled in special evaporators of anaesthetic machines, which are situated beyond the circulation circuits. This is the way of overdose prevention.
Mask fluothane-oxide-oxygearcosis was widely used in paediatric anaesthesiology, during short-term and small traumatic surgery. As medical narcosis – (manipulation of despair) – it is used for the immediate spasm relief when there is no venous access (epileptic state, seizures in case of eclampsia, meningitis, tetanus) for the treatment of bronchial spasm in patients with asthmatic conditions.
Fluothane anaesthesia is contraindicated for the patients with low blood pressure, deficiency of circulating blood volume (massive haemorrhage), heart failure, insufficiencies of parenchymal organs (liver-kidney failure).
4. Sevoflurane (Sevoran) was first synthesized in 1969 in the
Sevoran can be applied for initial anaesthesia, and for its maintaining. Sevoran is easily controlled: rapid induction of patients and quick recovery after termination of anaesthetic supply are its known benefits.
Initial narcosis is characterized by minimal excitement and absence of upper respiratory tract irritation. Sevoran causes dose-dependent inhibition of respiratory function and decrease of blood pressure. Therefore, its dose should be selected individually to achieve the desired effect, taking into account age and state of the patient.
Sevoflurane is administered by inhalation in a mixture of oxygen and nitrous oxide at a concentration of 0.5-3%, using the minimum-flow anaesthesia (0,5-2 litres of oxygen per minute). It also works with barbiturates, benzodiazepines and opioid analgesics.
Easiness of control, as well as minor side effects of sevoran (sleepiness after a general anaesthesia, dizziness, depression of respiratory and cardiac activity, rarely – nausea, vomiting) contributed to its wide introduction in anaesthesiology.
5. Isoflurane (forane) is a colourless inflammable liquid. It has high resistance to different agents, so it can be saved without special safety measures.
The main features of isoflurane anaesthesia are rapid falling asleep of the patient without excitement phenomena and the presence of analgesic effect after waking from anaesthesia. Isoflurane does not have toxic effects on respiration and cardiovascular system, however it has quite noticeable muscle relaxant effect. During forane anaesthesia tachycardia and increased tissue bleeding can occur.
6. Enflurane (Ethrane) was first described in 1968. It is a clear inflammable liquid with a sweetish odour. It does not cause excitement, has potent anaesthetic and weak analgesic effect (two times weaker than fluothane). During anaesthesia heart rate and respiratory rate increase, blood pressure decreases. It slightly depresses reflexes of the larynx and throat. According to the safety of its use it is placed between anaesthetic ether and fluothane. It can be combined with intravenous anaesthetics.
7. Xenon.
Xenon has been allowed for medical use as a preparation for inhalation general anaesthesia since 1999. This drug belongs to inert gases, that is why it does not enter into any chemical reaction in the body and it is not subjected to biological transformation. However, it has significant analgesic and anaesthetic effects (1.5-2 times more potent thaitrous oxide).
Clinical course of Xenoarcosis: after 5-6 inhalations of narcotic concentration of xenon the first stage occurs – peripheral paraesthesia and hypalgesia. Numbness and heaviness in the legs gradually rises upwards, spreading onto the skin of the abdomen, chest, neck and the head. In 2-3 minutes appears the second stage of euphoria and psychomotor activity, that is rapidly changing into the third stage of complete analgesia and partial amnesia. With the loss of consciousness, there is the fourth stage of complete analgesia and anaesthesia (corresponding to the first surgical stage of ether narcosis). At this stage, in conditions of mono-narcosis and spontaneous respiration, it is possible to perform surgery without the narcotic analgesics. Cardiovascular and respiratory systems (gas exchange) are stable.
Analgesia occurs in case of inhalation of 30-40% mixture with oxygen, the loss of consciousness occurs during inhalation of 65-70% of mixture. Muscle relaxation is quite significant. Recovery fast: in 2-3 minutes after gas supply is turned off, the patient is entirely conscious with pleasant subjective sensations.
Xenon can be used as an anaesthetic for various surgical operations, childbirth, painful manipulations; for relieving of pain attacks and treatment of pain syndromes and depression states in all fields of medicine, especially in patients of high risk groups. It is not toxic, that is why xenon should become an anaesthetic of choice, “gold reserve” during operations of patients with high anaesthesiology risk.
Xenon is used as a single component of anaesthesia (mask and endotracheal option) or in combination with various intravenous preparations: sedatives, narcotic and non-narcotic analgesics, neuroplegics, tranquilizers, gangliolytics etc.
Xenon can also be used for treatment at pre-hospital stage (emergency and urgent medical care to relieve pain in case of myocardial infarction, angina pectoris, burn or skeletal injuries, asthma attacks with the usage a special devices (mixture of Xe: O2 – 50:50). It can be used as an antidepressant ieurotic and stress-anxiety disorders and other neurological conditions, to relieve abstinent syndrome, in treatment of motor aphasia, dysarthria.
Non-inhalational anaesthesia occurs in case of the parenteral injection of anaesthetics. The most common way of administration is intravenous route.
1. Derivatives of barbituric acid.
Sodium thiopental (hexenal) was first described by Lundy in 1934. It is a powder of green (sodium thiopental) or white (hexenal) colour. It is produced in bottles of 0.5 and 1 gram. Immediately prior to anesthesia, this powder is dissolved with distilled water (isotonic solution of sodium chloride) up to 1% concentration.
Barbiturates have narcotic effect (cause unconsciousness) with minor pain relief effect. Therefore, they are used for initial narcosis, during the painless manipulations. For anaesthesia during barbituric narcosis it is necessary to introduce additional narcotic analgesics (morphine hydrochloride, phentanyl).
Easy, pleasant for the patient falling asleep and lack of excitement at the same time led to widespread use of sodium thiopental and hexenal in the practice of an anaesthesiologist.
In addition, due to strong anticonvulsant effect barbiturates are used for removal of cramps in patients with epilepsy, tetanus, meningitis, eclampsia etc.
Derivatives of barbituric acid have parasympathomimetic properties. Therefore, at the use of them the following complications are possible: cough, bronchial spasm, laryngeal spasm. They inhibit the activity of the respiratory centre, with fast intravenous administration of large doses of sodium thiopental or hexenal respiratory arrest is possible.
Barbiturates may be used only when the apparatus for artificial ventilation of the lungs is available!
A nurse – anaesthetist should prepare anaesthetic for anaesthesia and give it to the patient by the anaesthesiologist’s instruction. She should dissolve in aseptic conditions 1 gram of sodium thiopental in 100 ml of 0.9% solution of sodium chloride (up to 1% concentration). After venous puncture and managing system for infusion therapy (only by the anaesthesiologist’s instruction) she should introduce 1-2 ml of anaesthetic intravenously. Waiting for 1 – 2 minutes, she should determine if the patient has sensitivity to thiopental sodium, if the solution is not under the skin. Then she should introduce the rest of the drug. The dose of anaesthetic is especially individual (from 4 to 8 mg / kg of body weight). Barbituric narcosis lasts 15 – 30 minutes. To continue narcotic sleeping the patient should be administered 10 – 20 ml of 1% solution or use other anaesthetics.
2. Sodium oxybutyrate (GOBA).
Sodium salt of gamma-oxybutyric acid (GOBA) was first described by H. Laborit in 1960. It is produced in ampoules of 10 ml of 20% solution. It has sedative and narcotic effect. Anaesthetic effect is not significant.
Sodium oxybutyrate – derivative of gamma-aminobutyric acid – a natural metabolite of the organism. Therefore, its use does not cause toxic effects in patients. Involving in metabolic processes, GOBA normalizes cellular respiration, transmembrane potential, moving potassium from blood plasma into the cells, due to that excitation processes of cells of the heart, brain, etc. decrease.
Sodium oxybutyrate also belongs to the group of anti-hypoxants, so it is widely used in intensive care of patients with disabilities of the cardiovascular system (in shock), with severe hypoxic conditions (after having survived clinical death, brain damage, in obstetrics). Anti-hypoxic dose (20-40mg/kg body weight) effectively affects tissue respiration, optimizing it. GOBA at this dose does not influence on consciousness of the patient.
As a means of anaesthesia, it is a method of choice in accompanying diseases of the cardiovascular system, the liver, the kidneys, diseases of the endocrine organs, ieurosurgical operations and in the pathology of pregnancy. In the intravenous method, it can be used intramuscularly, orally, rectally.
For anaesthesia GOBA is used at a dose of 70 – 120 mg / kg of body weight. A nurse – anaesthetist introduces it, following doctor’s instructions, intravenously slowly by 10 ml. In order to prevent spasms, GOBA should be introduced together with barbiturates. For this 20-milliliter syringe should be filled with sodium oxybutyrate (10 ml) and sodium thiopental (10 ml). This mixture can be administered quickly. After repeated (3-5 times) injection of the mixture in 5 – 10 minutes the patient falls asleep, which resembles the physiological sleep. A rare, deep breathing, muscle relaxation, inhibition of reflexes are observed. Haemodynamics is not disturbed. Narcotic sleep lasts for 1 – 1,5 hours, its after-effect – up to 5 hours. At this time the patient needs to be looked after because retraction of the tongue, disorder of the lung ventilation may occur.
3. Ketamine.
Ketamine (ketanest, kalipsol, ketalar, velonarkon, petar) was described by Karsen and Domino in 1965. This group of drugs, has the ability to depress the function of some parts of the central nervous system and increase the activity of others, causing a so-called dissociative narcosis. Ketamine is a clear liquid, unstable to light, produced as 1 or 5% solution in bottles of darkened glass (10 ml), or in ampoules (2 ml). Ketamine is a strong anaesthetic, causing a deep sleep with moderate anesthesia. Due to selective stimulation of certain parts of the brain (limbic structures), during ketamine mono-narcosis patients may have visual hallucinations. In addition, ketamine causes a slight neuro-vegetative inhibition, relaxation of the cross – striated muscles with preserved tendon reflexes. It increases blood pressure, heart rate, slightly depresses respiration and stimulates the production of cerebrospinal fluid (liquor).
According to its characteristics ketamine is a tool of choice in patients with deficiency of circulating blood volume (hypohydration, hypotension, and various types of shock, collapse), in the need of anaesthesia with preserved spontaneous breathing. Due to its universal administration (intravenous, intramuscular and rectal) this anaesthetic is widely used in paediatric anaesthesiology.
Ketamine can be administered intravenously at doses of 2 – 3 mg / kg or intramuscularly at doses of 7-15 mg / kg. To avoid unwanted hallucinatory effect it is used with tranquilizer solution (1 – 2 ml of 0.5% sibazon solution).
Ketamine can be combined with various inhalation and non-inhalation preparations in the combined narcosis.
Ketamine anaesthesia is contraindicated for patients with hypertension, liquor hypertension (traumatic brain injury, epilepsy), with mental disorders.
4 Propofol (diprofil, diprivan, isoprivan).
The anaesthetic is produced in the form of white fat emulsion in 20 ml ampoules or bottles of 50 and 100 ml. 1 ml of preparation contains 10 mg of active substance. It can be administered intravenously with different infusion means (optimally – 5% glucose solution), except for blood and plasma (danger of deemulgation).
Propofol has a strong hypnotic and sedative effect, slight anaesthetic effect. Therefore, it should be used in combination with analgesics.
Intravenous injection at a dose of 2-2.5 mg / kg (15-20 ml) causes sleeping in 40 seconds (disappearance of the ciliary reflex). The duration of narcotic sleep is 20 – 30 minutes. Diprivan does not cause excitement, somewhat weakens the breathing, has a weak hypotensive effect without tachycardia. Inhibition of laryngeal reflexes and throat allows to apply laryngeal mask (a means of maintaining airway of the respiratory passages in self breathing and performing artificial ventilation of the lungs).
Diprivan is used for initial narcosis and as a component of balanced anaesthesia during long-term operations. This anaesthetic is injected again in 20 – 30 minutes at a dose of 100 mkg / (kg. min) – (fractional, by 2 ml, followed by a decrease at dose of ¼ each time of next administration or continuously, using a dispenser).
After diprivaarcosis (even long-term) the patients wake up fast during 10 minutes. This feature, as well as normalization of haemodynamics during laparoscopic surgery, the minimum number of complications and contraindications make propofol a drug of choice in modern anaesthesiology.
Combined general anaesthesia with muscle relaxants.
To achieve general anaesthesia most effectively use a combination of several anaesthetics should be. In these cases, the dose of each anaesthetic is reduced (and, respectively, their toxicity), therapeutic effect is increased. The use of muscle relaxants and muscle relaxation by themselves still reduce the need for anaesthetic, facilitating optimal performance of surgeons in the depth of the wound.
Muscle relaxants are divided into depolarizing and anti-depolarizing. The first are short-term, causing febrile twitching of the facial muscles, muscles of the trunk, the limbs, the diaphragm, followed by relaxation of the muscles and vocal cords up to 4-6 minutes. Ditylin (succinylcholine) is produced in ampoules of 5 ml of 2% solution, usually used for tracheal intubation at a dose of 2 mg / kg (7 – 10 ml) intravenously.
Anti-depolarizing muscle relaxants cause long-term (from 25 min. to 1,5 hours) muscle relaxation in patients without prior fibrillation, so they are used during prolonged operation on the organs of the abdominal cavity, the chest, etc. They include tubocurarine chloride, pavulon, arduan, tracrium. Arduan is produced in bottles, 4 mg of dry substance. Before the administration muscle relaxant should be dissolved in 2 ml of isotonic solution of sodium chloride, applied at a dose of 0.04 mg / kg (1.5-2 ml) intravenously, every 40 – 45 minutes the drug is re-administered in the half dose.
As a multi component intravenous narcosis with muscle relaxation and artificial ventilation of the lungs neuroleptanalgesia, ataralgesia, central analgesia are often used.
Neuroleptanalgesia (NLA). For NLA neuroleptic droperidolum and narcotic analgesics phentanyl are used either alone or in combination with other inhalation or non-inhalation anaesthetics.
Droperidolum is produced in bottles: of 10 ml transparent colourless liquid, which contains 25 mg of preparation (0.25% solution). The drug has a marked antishock effect: it blocks extra excitement of the sympathic-adrenal system, normalizes the activity of the reticular formation, relieves spasm of arterioles (alpha adrenolytic influence on the system of microcirculation), does not cause unconsciousness. Duration of the drug action is up to 3-4 hours.
Phentanyl is produced in ampoules of 2 ml of 0.005% solution. It has short-term analgesic effect (up to 30 minutes), which allows to manage anaesthesia by minimizing the risk of drug inhibition of the respiratory centre in patients in the postoperative period.
When using the classic technique of NLA is administered intravenously 0,25-0,5 mg/kg of droperidolum and 0.005 mg/kg of phentanyl (6-8 ml of droperidolum solution and 6-8 ml of phentanyl solution for 1 hour anaesthesia). To cause unconsciousness the respiratory mixture of dinitrogen oxide and oxygen in the ratio 70%: 30% is used. After the introduction of muscle relaxants the patient is intubated, artificial ventilation of the lungs is performed. To maintain narcosis 1-2 ml of droperidolum and phentanyl should be administered every 20-30 minutes. Tachycardia is indication for re-administration of phentanyl, hypertension for re-administration of droperidolum.
Neuroleptanalgesia is used for very weak patients with high operational risk, in disorder of haemodynamics and the need of artificial ventilation of the lungs in the postoperative period.
Ataralgesia is the way of general anaesthesia with sedation preparations (ataractics) and narcotic analgesics.
Ataractic seduxen (diazepam, relanium, sibazon) is produced in ampoules of 2 ml of 0.5% solution. It cannot be dissolved or mixed with other drugs (white precipitate is formed!).
For narcosis seduxen is administered at a dose of 0.3-0.5 mg/kg and intravenously mixture of dinitrogen oxide with oxygen (2:1) is used. Anaesthetic effect is obtained by introducing phentanyl fractionally or other narcotic analgesic (morphine hydrochloride, dipidolor, pentazocine) at doses as for NLA. To achieve muscle relaxation muscle relaxants are used, and to ensure adequate breathing – artificial ventilation of the lungs is used. During the surgery by indications (tachycardia, increased blood pressure) seduxen is re-administered (usually in 1,5 hour) and phentanyl (in 20-30 min.)
The advantage of this narcosis is its minimal adverse effects on various organs and systems so that ATA is used in patients with accompanying pathology of the heart, the liver, the kidneys etc.
Central analgesia is the way of narcosis in which anaesthesia, hyporeflexia and neuro-vegetative protection in patients is reached by administration of large doses of narcotic analgesics (1% morphine hydrochloride solution up to 20-30 ml, 0.005% of phentanyl solution – up to 100 ml). Other components (relaxation, unconsciousness, support of gas exchange and blood circulation) are used by general rules.
Central analgesia is indicated for patients with severe heart failure, combined heart defects, in case of prolonged artificial ventilation of the lungs in the postoperative period.
1.4 The work of anaesthetic team in the operating room
The success of anaesthesia and of surgery largely depends on accurate and coordinated actions of anaesthesiological team (a doctor-anaesthesiologist and nurses anaesthetists), their experience, concentration, knowledge, skills and available medical equipment.
Necessary medical equipment and instruments:
– system of centralized oxygen and nitrous oxide supply;
– anesthetic machine or artificial ventilation apparatus ( “Phase”, “
– equipment to monitor the functional state of the organism (cardiomonitor – for continuous ECG registration, pulse oximeter – for continuous measurement of oxygen saturation of the blood, volumeter – to monitor the volumes of inspiration and exhalation of the patient, tonometer, phonendoscope, stopwatch, etc.).
– electric pumps, laryngoscopes with a set of blades, set of intubation tubes;
-tools and details of devices: high pressure hose (to supply oxygen and dinitrogen oxide), masks for breathing apparatus, hose pipes, connectors, adapters, system of removal of exhaled gases.
– additional instruments: anaesthesiologist’s forceps, clamps, mouth dilator, syringe for inflating cuff endotracheal tubes, flexible conductors for tubes, a tray for bottles, a set of probes and catheters;
– an anaesthetist’s table, completed with preparations for narcosis, infusion therapy and others; system for infusion therapy, syringes, sterile rubber gloves, tourniquet, bandages.
An anaesthesiologist personally is responsible for the availability and serviceability of narcosis and respiratory apparatus and accessories, an anaesthetist –c for its asepsis and antisepsis, a table equipment and its management.
Before anaesthesia an anaesthesiologist must check:
-availability of oxygen in the system;
– working condition of narcosis and respiratory apparatus. He personally connects hoses of oxygen and dinitrogen oxide supply to the corresponding connecting pipes of dosimeters, turns on breathing apparatus, and having connected breathing circuit, checks it for hermetic. For this purpose, he closes by his finger adapter of breathing circuit of working apparatus, following the manometer. In its indications of 300 mm.of water column dehermetisation valve must operate;
-efficiency work of electric suction machine (having closed a rubber hose by finger, follows the vacuum manometer deflection);
-working condition of laryngoscopes. After its turning on the lamp must light;
-state of cardiomonitor, pulse oximeter.
Preparing an anaesthetist’s working place
While preparing the anaesthetist’s table to work one should follow the order of setting instruments and medical preparation for narcosis and intensive care.
First, a table is covered with a sterile cloth. Then successively disposable syringes are put: in the lower left corner – two of 20-milliliter for 1% thiopental sodium solution (hexenal, propofol) in the lower right corner – syringes for muscle relaxants: 10 ml of capacity for 2% Dithylin solution (listenon , myorelaxant) and 2 ml for 0.2% for arduan solution. Behind them 5-milliliter syringe is located for narcotic analgesics (0.005%. phentanyl solution). In the upper right corner there should be 5 ml syringe for solutions of sibazon, droperidolum, ketamine. In the upper left corner – syringes of 5 and 10 ml capacity for other drugs (ganglioblockers, clopheline, dalargin, etc.). Among them there are placed two glass vessels (of 100 ml of capacity) filled with 0.9%, sodium chloride solution. In the left bowl the powder of sodium thiopental is dissolved up to 1% concentration; 0.9% sodium chloride solution in the right bowl is used for dissolving other drugs just before their intravenous introduction.
In a separate tray must be sterile gauze wipes and forceps, next to a bottle with antiseptic solution (70% of ethyl alcohol).
The desk drawer is designed to store pharmacological preparations needed during surgery, intravenous catheters, disposable system for transfusions, adhesive plaster, etc.
On the shelf under the box an anaesthetist places the bottles of infusion-transfusion preparations.
In a separate tray a set for tracheal intubation is form: laryngoscopes with a set of blades (large, medium, small), intubation tubes of various sizes and throat mask, air-way, mouth dilator, a connector of the intubation tube, syringe for cuff blow of the intubation tube, Kocher clamp, napkins.
1.5. Complications of general anaesthesia, their prevention and treatment
Complications may occur at different stages of anaesthesia: during premedication, initial narcosis, during maintenance of narcosis and after narcosis period.
The most responsible for an anaesthesiologist stages are: giving anaesthesia, awakening and early after narcosis period.
The complications may be associated with:
a) the specific influence of anaesthetic;
b) the type and method of anaesthesia;
c) main or accompanying disease;
d) the nature of surgery.
The basis of prevention of complications is adequate preparation of the patient for surgery and anaesthesia, and careful monitoring of patients at all stages of anaesthesia.
Complications concerning the respiratory system are with the following disorders:
a) of airway of the air passages (accumulation of phlegm, tongue retraction, aspiration of vomit, laryngospasm, bronchospasm, etc.)
b) of the regulation of respiration (respiratory centre depression drugs, hypoxia, etc.)
c) of neuromuscular conduction (influence of muscle relaxants, antibiotics, disorder of electrolyte metabolism),
g) of the lungs (pneumonia, atelectasis, pulmonary oedema, etc.).
Any disorder of respiration leads to oxygen starvation (hypoxia) and accumulation of carbon dioxide (hypercapnia).
Hypoxia. Respiratory, or hypoxic hypoxia occurs during hypoventilation, respiratory passage disorders, reducing the oxygen volume in the inhaled mixture, pulmonary pathology. Characteristic feature is decreasing PaO2 <80 mmHg
Clinical characteristics of hypoxia. I stage of compensation (analeptic); II stage decrease of compensatory reactions (narcotic), III stage of decompensation (toxic).
At the first signs of hypoxia one should primarily:
a) to listen to the respiration of the patient of both lungs,
b) to ensure airway of the respiratory passages,
c) to check the narcosis apparatus and oxygen supply.
Hypercapnia occurs in hypoventilation of the lungs due to respiratory depression by anaesthetics or drugs, in case of non-physiologic operating position of the patient, absence or ineffectiveness of adsorbent, large amounts of “dead space”; in the postoperative period – with inadequate anaesthesia.
Hypercapnia stimulates the sympathic-adrenal system. The increase of blood pressure, increased salivation, bright red colour of the skin and mucous membranes, extra-systoles are observed. Dilatation of the capillary vessels leads to increased capillary bleeding, which is one of the reasons of delayed wakening from narcosis and can lead to cerebral oedema.
In case of hypercapnia it is necessary to normalize pulmonary ventilation (auxiliary artificial ventilation or mechanical ventilation), to replace chemical absorber iarcosis apparatus.
Complications concerning the cardiovascular system may be caused by inadequate gas exchange, changes in circulation blood volume, weakening of cardiac activity, disturbance of peripheral circulation, changes in rheological properties, clotting and fibrinolytic systems of the blood. Changing blood pressure, cardiac arrhythmia, cardiac arrest, embolism and thrombosis are observed:
Disorder of normal rhythm and beat of heart activity. Tachycardia occurs in abnormal gas exchange and transport of blood gas, blood loss, inadequate anaesthesia, reflex stimulation of the heart, administration of atropine sulphate, ether. Manifested tachycardia may be the precursor of fibrillation of the heart ventricles. Bradycardia. Its cause is severe hypoxia, stimulation of the vagus nerve, overdose of fluothane or methoxyflurane, administration of dithylin. It may precede cardiac arrest. Arrhythmia is the result of hypercapnia, stimulation of the vegetative nervous system receptors.
Treatment – adequate ventilation, neuro-vegetative blockade, in brady-arrhythmia – the introduction of atropine.
Arterial hypertension may occur due to hypercapnia, hypoxia, painful stress, effects of anaesthetics (ketamine) and adrenomymetics.
Arterial hypotension: a) with tachycardia is developed in hypovolemia of any origin. Treatment is to restore blood circulation volume. In cases of suspected acute adrenal insufficiency hormones are prescribed. In acute heart failure that is due to myocardial infarction or lack of blood and fluids transfusion cardio-tonics are administered;
b) with normocardia – occurs in decrease of vascular tone on a background of moderate vagotonia (sodium-thiopental narcosis). Vasopressors are prescribed;
c) with bradycardia – occurs in severe hypoxia, fluothane and narcotic analgesics overdose, vagotonia.
Having determined decrease of BP, an anaesthesiologist should stop giving anaesthetic and define the cause of hypotension!
Complications concerning the digestive system.
Vomiting is caused by hypoxia, hydration, the influence of anaesthetics (on the vomiting centre and the mucous membrane of the stomach), stimulation of reflexogenic zones (root of the tongue, pharynx).
Regurgitation occurs during mechanical ventilation of the lungs in patients with “full” stomach, lowering the head end during operation at the time of fibrillation of the muscles while administering dithylin for intubation. Lack of symptoms is dangerous prior to aspiration
Complications concerning the nervous system.
Slow awakening from general anaesthesia is caused by prolonged hypoxemia and hypercapnia, anaesthetics overdose, in children – on the basis of hypothermia.
Hypoxia of the brain can be complicated by brain oedema, focal lesions, decerebration. Spasms, mental disorders are possible. Normalization of gas exchange and adequate anaesthesia provide prevention of the complication of the CNS.
As the result of compression or dilatation of the peripheral nerves (brachial plexus, fibular nerve etc.) neuritis, paresis, paralysis can be observed.
To prevent the occurrence of this pathology you should put the limbs properly and control their position during surgery and in postoperative period.
Disorders of thermoregulation. Hypothermia (spontaneous) occurs on the basis of increased heat loss and blockade of thermoregulation centres. To prevent the development of this disease, you should maintaiormal body temperature.
Malignant hyperthermia occurs most often in young people and in children in postoperative period. During the operation use of muscle relaxants, fluothane and other drugs should be made with particular caution.
Anaesthesia is meant to protect the body from operating injuries, but it can also be a cause of serious reactions and complications by itself. Therefore, an anaesthesiologist should inform the patient before surgery about possible complications, side effects and consequences of anaesthesia.
Complications of anaesthesia and the effects of narcosis are divided into:
1. Common: nausea, sore throat, tremor, dizziness and disturbance of consciousness, headache, itching, pain in the back and lumbar, muscle pain, confused consciousness.
2. Uncommon: postoperative pulmonary infection, injury of the teeth, the lips, the tongue, awakening during general anaesthesia.
3. Rare and very rare: nerve damage associated with general anaesthesia, nerve injury associated with regional anaesthesia, allergic reaction (anaphylaxis), injury of the eyes during general anaesthesia, death or brain injury.
Common side effects and complications of anaesthesia.
Nausea is a frequent result of anaesthesia, which occurs in about 30% of cases in the postoperative period. Nausea is often typical to the general, than regional anaesthesia. For its prevention it is necessary to provide a patient with adequate pain relief, he/she should not be active during the first hours after surgery – to sit and get up, to drink water and to eat. Deep breath with slow inhalation of the air can decrease nausea.
Sore throat. It can vary from discomfort to severe constant pain during talking or swallowing. The mouth can be dry. These symptoms may be a few hours after surgery, and may remain for two more days.
Tremor, as the result of anaesthesia is a frequent problem because it causes great discomfort, although it is not a danger to the organism and lasts about 20-30 minutes. Tremor may occur after general anaesthesia and be a complication of epidural and spinal anaesthesia. The thermal comfort of the patient before and during surgery decreases the probability of tremor occurrence.
Dizziness and loss of consciousness. The residual effect of anaesthetics may cause decrease of blood pressure, in addition dehydration can cause the same effect, which is not so rare after surgery. Decreased blood pressure may cause dizziness, weakness, loss of consciousness.
Headache. It can be caused by a drug used for anaesthesia, the operation itself, dehydration and the patient’s anxiety. Often headache disappears in a few hours after anaesthesia and is treated with analgesics easily. A severe headache may be a complication of spinal or epidural anaesthesia.
Itching. Usually it is adverse reaction to anaesthesia medication (e.g. morphine), but itching may be a manifestation of an allergic reaction.
Backache and pain in the lumbar. During the operation the patient is in a constant position on a firm operating table for a long time, which may cause “tired” back and lead to backache after surgery.
Pain in the muscles. Most often this pain occurs in young males, it is often associated with the use of muscle relaxants during anaesthesia, particularly dithylin. Pain in the muscles is the result of narcosis (general anaesthesia), it is symmetrical, often localized in the neck, the shoulders, the upper abdomen and lasts until 2-3 days after surgery.
Confused consciousness. Some patients, usually elderly, suffer from confused consciousness after surgery and anaesthesia. Their memory may deteriorate, and their behaviour may differ from typical for them usual state.
Uncommon side effects and complications of anaesthesia.
Postoperative pulmonary infection. This problem is the most common consequence of narcosis (general anaesthesia). A few simple measures will significantly reduce the risk of this complication:
– Smokers should quit smoking for about 6 weeks before surgery;
– The patients with chronic lung disease should be operated in a state of remission;
– Adequate pain relief after surgery is the key to effective breathing and ability to cough, and, consequently, to reduce the risk of pulmonary infection.
Injuries of the teeth, the lips, the tongue. General anaesthesia is a risk for teeth injury, which occurs in about 1 case in 45,000 anaesthesias. Minor injuries of the lips or the tongue are common in about 5% of cases of general anaesthesia.
Awakening during anaesthesia. Some of the patients during surgery may come to consciousness, they can remember some episodes of the operation. It is very unpleasant complications of anaesthesia, however, it is quite a rare event, since the modern system of monitoring can prevent the development of such complication.
Rare and very rare side effects and complications of anaesthesia.
Nerve injury, as a complication of anaesthesia. This type of complication is characterized by a sense of numbness, tingling or pain. There may be a disorder of heat or cold sensitivity. Additionally, there may be a feeling of weakness or paralysis. Typically, all complaints disappear in a few days or months. Complete recovery can sometimes be delayed up to a year. The most common is ulnar nerve injury in the ulna nerve area and fibular nerve in the knee.
Nerves may be injured during epidural and spinal anaesthesia. This complication is rare and usually disappears within a few weeks or months. Cases of temporary immobilization (paralysis) of one or two extremities are very rare (1:50 000).
Reasons that may cause nerve injury:
– Nerve may be injured by a surgeon during some operations (it is sometimes difficult and unavoidable);
– The position in which the patient lies on the operating table can lead to nerve compression or tension, damaging it;
– The use of turnstiles by a surgeon to reduce the amount of blood loss during surgery puts pressure on the nerve, also contributing to its injury;
– The cause of nerve compression may be post-operative swelling of the tissues.
Allergic reaction (anaphylaxis). During anaesthesia, as well as, during the patient’s stay in hospital medications may cause severe allergic reaction – anaphylaxis. The frequency of development is 1:15000 of anaesthesia. Usually, an anaesthesiologist successfully diagnoses and treats this terrible complication, however, statistically one of twenty of such severe reactions can lead to death.
Injury of the eyes during general anaesthesia. This is a rare complication of narcosis. The most frequent type of eye injury during and after general anaesthesia is damage of the cornea (1:2000 anaesthesias). This condition does not affect visual acuity, but may cause a dark point in the damaged eye. Most corneal injury is due to the fact, that during anaesthesia the patient’s eyelids are not always completely closed. Consequently, the cornea becomes dry and the eyelid “sticks” to it from inside. Then, when the patient opens the eyes and corneal injury occurs.
Death or brain injury.
1.6. Postoperative care of surgical patients
After complex operations the patients are transferred to the department of intensive therapy. Medical personnel of the department should continuously look after the patients (monitor vital functions) and provide intensive care.
During the postoperative period of patients after long hours of surgery under general anaesthesia combined with the use of muscle relaxants, a special attention should be paid to the respiratory function and the cardiovascular system activity.
The patients, who underwent complicated surgery, particularly on the digestive organs of the gastrointestinal tract, should be provided with a balanced intensive care for a long period of time until the restoration of the physiological processes of digestion.
Planned postoperative prescriptions (general regulations):
1) administration of adequate analgesia (with the use of narcotic and non-narcotic analgesics);
2) prescribing infusion therapy (at a rate of 40 ml per 1 kg of body weight per 24 hours – the regime of moderate haemodilution)
3) providing the organism with the most important electrolytes (daily need: Na+ – 2 mmol / kg, Cl- – 2 mmol / kg, K + – 1 mmol / kg, Mg + + – 0.2 mmol / kg, Ca + + – 0, 3 mmol / kg)
4) prescribing parenteral nutrition to the patient, based on
– The necessary energy providing – 25 kcal / kg per 24 hours;
– The daily need of proteins should be 1.4 g/kg;
– The ratio of ingredients for parenteral nutrition:
proteins: carbohydrates: fat = 2: 7: 1,
– It is necessary to prescribe vitamins (at the therapeutic dose);
5) by indications, with a prophylactic or therapeutic purpose, the administration of antibiotics;
6) maintaining therapy, aimed at preventing decompensation of the main and probable accompanying pathology;
7) symptomatic therapy;
8) physiotherapy treatment and exercise therapy;
9) providing different laboratory and instrumental investigations.
Example. A 47-year-old patient K., 72 kg, survived operation on stomach cancer. Surgery – gastrectomy. Accompanying pathology: chronic bronchitis of a smoker.
The patient was prescribed:
1) for pain – 1% promedol solution, 1 ml intramuscular;
2) 0.9% sodium chloride solution – 800 ml, drip intravenously;
3) 10% solution of glucose – 400 ml
7.5% potassium chloride solution – 20 ml
25% magnesium sulphate solution – 3 ml
insulin solution – 12 units;
to administer intravenously, drip, 3 bottles (1270 ml) during 4 hours;
4) 8%polyamines solution – 400 ml;
5) 20% intralipid solution – 500 ml, drip intravenously during 3 hours;
6) 20% glucose solution – 400 ml
insulin solution 24 units;
to administer intravenously, drip slowly during 2 hours;
7) Vitamin C, 5% solution, 5 ml intravenously, 3 times (at 8.00, 16.00, 24.00)
vitamins B1, B6 – 1 ml intramuscular;
8) ceftriaxone 1g intravenously twice a day (at 10.00 and at 22.00);
9) Steam inhalation with sodium hydrocarbonate solution, coltsfoot infusion;
10) exercise therapy, breathing exercises with the creation of positive pressure on exhalation;
11) Laboratory tests: blood analysis, hematocrit, biochemical blood analysis (glucose, proteinogram, coagulogram, amylase, bilirubin, Na, K, Cl, options of acid-base state, the toxicity of blood serum), urinalysis.
1.7. Medical manipulations and operations
Tracheal intubation
Indications: the necessity of artificial ventilation of the lungs in patients with combined anaesthesia using muscle relaxants, providing respiratory care to patients with acute and chronic respiratory failure, making manipulation (bronchoscopy) in tracheal-bronchial tree, performing cardiopulmonary-cerebral resuscitation.
Necessary equipment: A laryngoscope with a set of blades, intubation tubes of different sizes, electrical or mechanical suction machine, apparatus for artificial ventilation of the lungs, atropine sulphate solution, preparations for anaesthesia and muscle relaxants, gauze napkins, phonendoscope.
Methods of intubation. The trachea is often intubated by mouth with laryngoscope in direct laryngoscopy.
For prevention of pathological reflexes the patient is previously injected intravenous 0.1% atropine sulphate solution (0.4 – 0.5 ml) and anaesthetic (e.g. sodium thiopental) for narcosis.
Mask way is used for additional artificial ventilation of the lungs with oxygen, along with administration of muscle relaxation solution.
After full muscle relaxation an anaesthesiologist opens the patient’s mouth by his right hand fingers (grasps the incisors of the upper jaw with the second finger tip and moves the chin down with the third finger), he takes the working laryngoscope by his left hand and gently introduces its blade into the mouth cavity.
Pic. 1.1 A laryngoscope is putted into the oral cavity.
The root of the tongue is pulled up, the soft palate and the tonsils are visible
Without efforts, carefully in order not to injure soft tissues, he moves the blade deep and medially into, pushing the tongue to the left. The entrance in the throat in and back wall of the throat are visible. With further introduction of the blade the larynx-throat opens with overhanging layer of its epiglottis. An anaesthesiologist displaces it upwards (when using direct blade takes the epiglottis free end and raises it up; while using indirect laryngoscope puts it under the basis of the epiglottis and pressing shifts it upwards). The entrance to the trachea opens, formed by the glottis of inverted trapezoid form. Its side walls are the vocal cords.
Pic. 1.2-3 The epiglottis is raised by the laryngoscope’s blade.
The glottis is visible
By his right hand an anaesthesiologist gently introduces the intubation tube of appropriate size into the glottis, so that its blowing cuff was hidden immediately behind the vocal chords.
The intubation tube is connected to the triple connector of respiration circuit of the apparatus of artificial ventilation of the lungs. Tube cuff of the tube is blown with air, due to that it obturates free lumen of the trachea and seals system “the lungs – apparatus of artificial ventilation of the lungs”.
He checks accuracy of the intubation tube position in the trachea, listening to the breathing with phonendoscope on both sides of the chest. In all regions of the lungs vesicular breathing the same sonority should be available (without abnormal noise).
The intubation tube is fixed by adhesive plaster or a bandage, around the patient’s head.
In the case of clinical death for effective ventilation of the lungs the trachea should be immediately intubated, without prior administration of anaesthetics. At presence of the mucus, the blood, the gastric contents or foreign bodies in the mouth and the throat an anaesthesiologist performs sanitation of the respiratory passages before the intubation, using electrical or mechanical suction machine or a gauze tampon at the clips.
Epidural anaesthesia.
Indications: anaesthesia in surgery on the abdomen, the pelvis and the lower extremities; intensive therapy of pathological conditions in which a temporary medication denervation of appropriate segments of the body is necessary (asthmatic status, myocardial infarction, pulmonary oedema, acute pancreatitis, paralytic intestinal obstruction, frostbite of the lower limbs etc.).
Picture 1.4 Choice of the place for puncture in epidural anaesthesia, depending on the required level of anaesthesia
Necessary equipment: a needle with a stylet for puncture of epidural space (Tyoxi), Dyufo needle, a needle for intramuscular injections, syringes of 2 ml of capacity with a light piston moving and of 10 ml with the adapter to the catheter, epidural catheter, Kocher clamp, sterile gauze tampons, a solution of ethanol, adhesive plaster, the solution of local anaesthetic.
Methods of administration
The equipment is placed on the sterile surface (a nappy) of the manipulation table.
The patient is placed on the operating table lying on his side or sitting, bending his body maximum (moving the head to the knees).
A place for puncture is chosen, according to the indications (the required level of anaesthesia).
The operating field and the anaesthesiologist’s hands are washed according to the rules of asepsis and antisepsis.
Infiltration anaesthesia of soft tissues from the puncture along the needle (introducing it in the sagittal direction, in the middle between the osseous processes of the spine) is administered.
Piercing the skin and subcutaneous fat tissue with Dyufo needle, creating a channel of 2 – 2.5 cm in depth.
Along the channel in the sagittal direction Tyoxi needle with a stylet is introduced in a depth of 3 – 4 cm, piercing upper osseous and intra-osseous ligaments.
Picture. 1.5 Sequence in which needle penetrates the tissues
moving it into the epidural space.
1 – the introduction of anaesthetic into the subcutaneous tissue;
2 – the needle – between osseous ligaments;
3.4 – the tip of the needle is in the epidural canal, the anaesthetic is injected easily (3), and it does not flow (4).
A 2 ml syringe is filled with isotonic sodium chloride solution, so that it contained a small air bubble. A stylet is removed from the Tyoxi needle and the syringe should be attached to its cannula. Continue to push gently the needle, while easily pressing the syringe piston. Monitor the air bubble. After passing the yellow ligament with the needle “a downfall” is felt: the syringe piston moves freely forward with the slightest effort of the anaesthesiologist, an air bubble is not deformed. The syringe should be carefully disconnected, leaving in the cannula a hanging drop of isotonic solution. The patient is asked to take a deep breath. Drawing of the drops into the cannula confirms that the tip of the needle is in the epidural space.
If one-stage anaesthesia is expected, the patient is injected into the epidural space a test-dose of anaesthetic first (3 – 5 ml 2% lidocaine solution), and in the absence of symptoms of spinal anaesthesia – in 5 minutes – a full dose of anaesthetic.
In case of a long-term anaesthesia the epidural space is catherized, moving the catheter through the Tyoxi needle to a depth of 7 – 8 cm. The needle is carefully removed, an aseptic bandage is put on the place of the puncture, and the catheter is fixed to the skin by adhesive plaster. A syringe with adapter is attached to the outer end of the catheter. First a test dose is administered and then, in the absence of symptoms of spinal anaesthesia – the rest of the required dose of anaesthetic.
Conductive anaesthesia.
In large traumatic operations (femur amputation, under-knee leg amputation) the most reasonable is the use of methods of conductive anaesthesia by blocking the sciatic and femoral nerve in the proximal regions.
The rear (proximal) blockade of the sciatic nerve (according to Rai).
Indications: In case of large operations (usually amputation of the lower third of the thigh), especially when the patient in some reason cannot be placed on the side or on the abdomen.
Necessary equipment: a 10-centimeter needle type UP 20G cut on 15-30 degrees; an anaesthetic – 20-30 ml of 1% xylonest solution (or mepivacaine, or lidocaine).
Anatomical orientation: a large trochanter of the femur, a sciatic tuber.
Methods of administration. The patient’s position: on the back, the assistant lifts up the patient’s leg, bending it at 90 degrees in the hip and knee joints. An anaesthesiologist marks the line between the large trochanter and the sciatic tuber, strictly in the middle of which, perpendicular to the skin introduces the needle, pushing it into the cranial direction.
At a depth of 5-10 cm during electrical stimulation (0.3 mA / 0.1 ms) foot bending appears (fibular nerve stimulation) or its extension (tibial nerve stimulation);
Blockade of the femoral nerve in the inguinal region (by Vinnie Rosenblatt).
Indications: In case of large operations (amputation of the lower limb).
Necessary equipment: a 5-centimeter needle type UP 18G; an anaesthetic – 20-30 ml of 1% xylonest solution (or mepivacaine, or lidocaine).
Anatomical orientation: the inguinal fold, the femoral artery.
Methods of administration. The patient’s position on his/her back, the lower limb is slightly drawn aside and rotated outward. The place of injection: 2 cmbelow the inguinal fold and 1.5 cm outside of the artery. A needle with electric stimulator is injected at an angle of 30 degrees into the skin in cranial direction to the sense of a double downfall on the passage of two fascias. Motor response is proved by contraction of the quadratus femoris muscle and the patella tingling during electrical stimulation 0.3 mA / 0.1 ms
The distal sciatic nerve blockade (by Meyer).
Indications:
– Anaesthesia during operations on the foot and the ankle joint;
– Treatment of chronic pain, postoperative analgesia of the tissues located distal to the knee joint;
– Sympathycolise in diabetic gangrene, disorder of the peripheral circulation and in treatment of wounds of the legs and the feet, which do not heal for along time.
Necessary equipment: a 5-10 centimeter needle type UP 22G; an anaesthetic – 20-30 ml of 1% xylonest solution (or mepivacaine, or lidocaine).
Anatomical orientation: the popliteal fold, fossa poplitea, arteria poplitea.
Methods of administration. The patient should be placed on the side of a healthy limb, which is bent in the knee and thigh joints. The injured limb should be straightened out; between the legs a small pillow is placed. Side protuberances of the knee are fixed by a thumb and middle finger (two bottom corners of the triangle), and by the index finger – top of an equilateral triangle, which limits the upper half of the popliteal fossa. The point of injection should be determined, which is 1-2 cmoutside of the top of the triangle, near the medial edge of the tendon of the thigh biceps muscle. A needle is introduced at an angle of 30-45 degrees into the skin in the cranial and slightly medial direction to a depth of 4-
Remarks.
The sciatic nerve is always outside of the popliteal artery.
The distal sciatic nerve blockade is particularly effective for prolonged anaesthesia. For this purpose the needle 19,5 G and catheter 20G should be used, which is injected to a depth of 4-5 cm cranially from needle cut. The anaesthetic is administered at a speed of 6 ml/hour, with optimum use of continuous administration of anesthetic by infusion pump.
1.8. Control tests and tasks
1. Preparations of sodium thiopental are produced
A – in ampoules (10 ml of 20% solution);
B – in bottles (
C – in ampoules (10 ml of 1% solution);
D – in ampoules (10ml of 20% solution);
E – in bottles of 4 mg.
2. Arduan – is
A – a non-inhalation anaesthetic;
B – a depolarizing muscle relaxant;
C – anti-depolarizing muscle relaxant;
D -a narcotic analgesic;
E – an inhalation anaesthetic.
3. In administering neuroleptanalgesia are used:
A- droperidolum and seduxen;
B – phentanyl and seduxen;
C – phentanyl and droperidolum;
D – morphine and sodium thiopental;
E – phentanyl and ketamine.
4. In administering ataralgesia are used:
A – droperidolum and seduxen;
B – phentanyl and seduxen;
C – phentanyl and droperidolum;
D – morphine and sodium thiopental;
E – phentanyl and ketamine.
5. Diprivan is produced
A – in ampoules (10 ml of 20% solution);
B – in bottles (
C – in ampoules (10 ml of 1% solution);
D – in ampoules (10ml of 20% solution);
E – in bottles of 4 mg.
6. Signs of fluothane overdose:
A – tachycardia;
B – hypertension;
C – hypotension and bradycardia;
D – comma, asystolia;
E – maximum constriction of the pupils.
7. At what stage of ether narcosis the pupils’ reaction to the light disappears:
A – Ι
B – ΙΙ
C – ΙΙΙ1
D – ΙΙΙ2
E – IV
8. Ether is expedient to be administered to patients with:
A – hypotension due to blood loss;
B – acute liver failure;
C – bronchitis;
D – acute renal failure;
E – diabetes mellitus.
Task 1
A 45-year-old patient G., is prepared for planned surgery on the stomach ulcer. Case history: diabetes mellitus, daily receives 28 units of insulin. At the time of examination glycaemia has been compensated. Objectively: the respiratory and the cardiovascular systems are in the normal state. Increased indices of urea (9,6 mmol / l) and creatinine (0,12 mmol / l).
Determine the degree of operating and anaesthesiological risk.
Task 2
During administering mask narcosis an anaesthesiologist noted the patient’s sudden inspiration dyspnoea with inability to make an active inspiration. The patient’s face became cyanotic, the neck veins became swollen, the pupils became dilated.
Specify the complication, its probable causes and sequence of nurse (anaesthetist) actions.
Task 3
What preoperative preparation does a 73-year-old patient S. need? He has been admitted to the surgical department with clinical signs of adhesive intestinal obstruction. On examination of the patient hypotension (BP -90 and 60 mm Hg.), tachycardia (heart rate – 112 per minute) have been revealed
Task 4
During intravenous anaesthesia the patient’s breathing became discontinuous, noisy, “gurgling”: from the mouth gastric content appeared. What has happened? Determine the sequence of emergency aid.
Task 5
While performing tracheal intubation, an anaesthesiologist observed stomach contents in the mouth of the patient, which slowly moved between the vocal chords into the trachea.
Determine the type of complication, its cause and probable course of the disease, and emergency aid that is necessary for the patient.
Task 6
An anaesthesiologist performed intubation to the patient and connected the intubation tube to the breathing apparatus. With air supply there appeared typical “gurgling” sound. Simultaneously, in the patient began to project epigastric area of the abdomen, breathing in the chest was not available.
Determine the type of complication and urgent aid.
Fluid imbalance and principles of its intensive treatment.
Water imbalance is divided into dehydration and overhydration.
Dehydration is caused by:
– excessive perspiration in conditions of high temperature;
– rapid breathing (dyspnea, tachypnea) or artificial ventilation without humidification of the air;
– vomiting, diarrhoea, fistulas;
– blood loss, burns;
– diuretics overdose;
– excessive urine output;
– inadequate enteral and parenteral nutrition or infusion therapy (comatose patients, postoperative care);
– pathological water distribution (“third space” in case of inflammation or injury).
Dehydration signs: weight loss, decrease of skin turgor and eyeballs tone, dry skin and mucous membranes; low central venous pressure, cardiac output and blood pressure (collapse is possible); decreased urine output and peripheral veins tone; capillary refill over 2 seconds (microcirculation disorders) and low skin temperature; intracellular dehydration is characterized with thirst and consciousness disorders. Laboratory tests show blood concentration: hematocrit, hemoglobin concentration, protein level and red blood cells concentration increase.
Overhydration appears in case of:
– excessive water consumption, inadequate infusion therapy;
– acute and chronic renal failure, hepatic and cardiac insufficiency;
– disorders of fluid balance regulation;
– low protein edema.
Clinical findings in case of overhydration are: weight gain, peripheral oedema, transudation of the plasma into the body cavities (pleural, abdominal), high blood pressure and central venous pressure. In case of intracellular overhydration appear additional symptoms: nausea, vomiting, signs of cerebral edema (spoor, coma). Laboratory tests prove hemodilution.
According to the osmotic concentration of plasma dehydration and overhydration are divided into hypotonic, isotonic and hypertonic.
Isotonic dehydration is caused by equal loss of electrolytes and fluid from the extracellular space (without cellular disorders).Blood tests show hemoconcentration; sodium level and osmotic concentration are normal.
To treat this type of water imbalance use normal saline solution, Ringer solution, glucose-saline solutions, etc.. The volumes of infusions can be calculated according to the formula:
VH2O= 0,2*BW* (Htp-0,4)/0,4 ,
VH2O – volume of infusion, l
Htp – patient’s hematocrit, l/l,
BW – body weight, 0,2*BW – volume of extracellular fluid,
0,4- normal hematocrit, l/l,
Hypertonic dehydration is caused by mostly water loss: first it appears in the vascular bed, than in the cells. Laboratory tests show hemoconcentration: elevated levels of proteins, red blood cells, hematocrit. Plasma sodium is over 155 mmol/l and osmotic concentration increases over 310 mOsm/l.
Intensive treatment: if there is no vomiting allow patients to drink. Intravenously give 0,45% saline solution and 2,5 % glucose solution, mixed with insulin. The volume of infusions is calculated according to the formula:
VH2O=0,6*BW (Nap -140)/140,
VH2O – water deficiency, l
Nap – plasma sodium, mmol/l
BW – body weight, 0,6*BW volume of general body fluid
140 – physiological plasma sodium concentration
Hypotonic dehydration is characterized with clinical features of extracellular dehydration. Laboratory tests show decrease of sodium and chlorine ions. Those changes cause intracellular movement of the water (intracellular overhydration). Hemoglobin, hematocrit and protein levels are increased. Sodium is lower than 136 mmol/l, osmolarity is lower than 280 mOsm/l.
To treat this type of water imbalance use normal or hypertonic saline and sodium bicarbonate solution (depends on blood pH). Do not use glucose solutions!
The deficiency of electrolytes is calculated according to the formula:
Nad = (140-Nap)*0,2 BW,
Nad – sodium deficiency, mmol
Nap – plasma sodium, mmol/l
BW – body weight, 0,2 BW – volume of extracellular fluid
Isotonic overhydration is caused by excess of the water in the vascular bed and extracellular space; however intracellular homoeostasis is not violated. Hemoglobin is less than 120 g/l, protein level is less than 60 g/l, plasma sodium is 136-144 mmol/l, osmotic concentration is 285-310 mOsm/l.
Treat the reason of imbalance: cardiac failure, liver insufficiency, etc. Prescribe cardiac glycosides, limit salt and water consumption. Give osmotic diuretics (mannitol solution 1,5 g/kg), saluretics (furosemide solution 2 mg/kg), aldosterone antagonists (triamterene – 200 mg), steroids (prednisolone solution 1-2 mg/kg) albumin solution if necessary (0,2-0,3 g/kg).
Hypertonic overhydration is a state of extracellular electrolytes and water excess combined with intracellular dehydration. Blood tests show decrease of hemoglobin, hematocrit, protein level, however sodium concentration is increased over 144 mmol/l, osmotic concentration is over 310 mOsm/l.
To treat this condition use solutions without electrolytes: glucose with insulin, albumin solutions and prescribe saluretics (furosemide solution), aldosterone antagonists (spironolactone). If it is necessary perform dialysis and peritoneal dialysis. Do not use crystalloids!
Hypotonic overhydration is a state of extracellular and intracellular water excess. Blood tests show decrease of haemoglobin, hematocrit, proteins, sodium and osmotic concentration. Intensive therapy of this condition includes osmotic diuretics (200-400 ml of 20% mannitol solution), hypertonic solutions (50 ml of 10% saline intravenously), steroids. When it is required use ultrafiltration to remove water excess.
9.4 Electrolytes disorders and their treatment
Potassium is a main intracellular cation. Its normal plasma concentration is 3,8-5,1 mmol/l. Daily required amount of potassium is 1 mmol/kg of body weight.
Potassium level less than 3,8 mmol/l is known as kaliopenia. Potassium deficiency is calculated according to the formula:
Kd= (4,5-Kp)*0,6 BW
K- potassium deficiency, mmol;
Kp – potassium level of the patient mmol/l;
0,6*BW – total body water, l.
To treat this state use 7,5% solution of potassium chloride (1ml of this solution contains 1 mmol of potassium). Give it intravenously slowly with glucose and insulin (20-25 ml/hour). You can also prescribe magnesium preparations. Standard solution for kaliopenia treatment is:
10% glucose solution 400 ml
7,5% potassium chloride solution 20 ml
25% magnesium sulphate solution 3 ml
insulin 12 units
Give it intravenously slowly, during one hour. Forced bolus infusion of potassium solutions (10-15 ml) can bring cardiac arrest.
Potassium level over 5,2 mmol/l is a state called hyperkalemia. To treat this condition use calcium gluconate or calcium chloride solutions (10 ml of 10% solution intravenously), glucose and insulin solution, saluretics, steroids, sodium bicarbonate solution. Hyperkalemia over 7 mmol/l is an absolute indication for dialysis.
Sodium is the main extracellular cation. Its normal plasma concentration is 135-155 mmol/l. Daily required amount of potassium is 2 mmol/kg of body weight.
Sodium concentration which is lower than 135 mmol/l is known as hyponatraemia. This condition is caused by sodium deficiency or water excess. Sodium deficiency is calculated according to the formula:
Nad= (140-Nap)*0,2 BW,
Na- sodium deficiency, mmol;
Nap – sodium concentration of the patient mmol/l;
0,2*BW – extracellular fluid volume, l.
To treat it use normal saline (1000 ml contains 154 Na mmol) or 5,8% solution of sodium chloride – your choice will depend on osmotic concentration.
Sodium concentration over 155 mmol/l is a state called hypernatremia. This condition usually appears in case of hypertonic dehydration or hypertonic overhydration. Treatment was described in the text above.
Chlorine is the main extracellular anion. Its normal plasma concentration is 98-107 mmol/l. Daily requirement of chlorine is 215 mmol.
Hypochloremia is a condition of decreased plasma chlorine concentration (less than 98 mmol/l).
Chlorine deficiency is calculated according to the formula:
Cld = (100-Clp)*0,2 BW,
Cld- chlorine deficiency, mmol
Clp – plasma chlorine concentration of the patient, mmol/l
0,2*BW – extracellular fluid volume, l.
To treat hypochloremia use normal saline (1000 ml contains 154 mmol of chlorine) or 5,8% sodium chlorine solution (1 ml contains 1 mmol of chlorine). The choice of solution depends on the osmotic concentration of the plasma.
Hyperchloremia is a condition of increased chlorine concentration (over 107 mmol/l). Intensive therapy of this state includes treatment of the disease, which caused it (decompensated heart failure, hyperchloremic diabetes insipidus, glomerulonephritis). You can also use glucose, albumin solutions and dialysis.
Magnesium is mostly an intracellular cation. Its plasma concentration is 0,8-1,5 mmol/l. Daily requirement of magnesium is 0,3 mmol/kg.
Hypomagnesemia is a state of decreased magnesium concentration: less than 0,8 mmol/l. Magnesium deficiency is calculated according to the formula:
Mgd =(1,0 – Mgp)*0,6BW,
Mgd – magnesium deficiency, mmol
Mgp – plasma magnesium concentration of the patient, mmol/l
0,6*BW – extracellular fluid volume, l.
Use 25% magnesium sulphate solution to treat this state (1 ml of it contains 0,5 mmol of magnesium).
Hypermagnesemia is a state of increased magnesium concentration (more than 1,5 mmol/l). This condition appears usually in case of hyperkalemia and you should treat it as you treat hyperkalemia.
Calcium is one of the extracellular cations. Its normal concentration is 2,35-2,75 mmol/l. Daily requirement of calcium is 0,5 mmol/kg.
Calcium concentration less than 2,35 mmol/l is called hypocalcemia. Calcium deficiency is calculated according to the formula:
Cad = (2,5-Cap)*0,2 BW,
Cad – calcium deficiency, mmol
Clp – plasma calcium concentration of the patient, mmol/l
0,2*BW – extracellular fluid volume, l.
To treat this state use 10% calcium chloride (1 ml of the solution contains 1,1 mmol of calcium), ergocalciferol; in case of convulsions prescribe sedative medicines.
Hypercalcemia is a condition with increased calcium concentration (over 2,75 mmol/l). Treat the disease, which caused it: primary hyperparathyroidism, malignant bone tumors, etc. Additionally use infusion therapy (solutions of glucose with insulin), steroids, dialysis and hemosorbtion.
9.5 Acid-base imbalance and its treatment.
There are 2 main types of acid-base imbalance: acidosis and alkalosis.
pH is a decimal logarithm of the reciprocal of the hydrogen ion activity. It shows acid-base state of the blood.
Normal pH of arterial blood is 7,36-7,44. Acid based imbalance is divided according to the pH level into:
pH 7,35-7,21 – subcompensated acidosis
pH < 7,2 – decompensated acidosis
pH 7,45-7,55 – subcompansated alkalosis
pH > 7,56 – decompensated alkalosis
Respiratory part of the acid-base imbalance is characterized with pCO2. Normally pCO2 of arterial blood is 36-44 mm Hg. Hypercapnia (pCO2 increased over45 mm Hg) is a sign of respiratory acidosis. Hypocapnia (pCO2 less than 35 mm Hg) is a symptom of respiratory alkalosis.
Basis excess index is also a characteristic of metabolic processes. Normally H+ ions produced during metabolic reactions are neutralized with buffer system. BE of arterial blood is 0±1,5. Positive value of BE (with +) is a sign of base excess or plasma acid deficiency (metabolic alkalosis). Negative value of BE (with -) is a symptom of bases deficiency, which is caused by acid neutralization in case of metabolic acidosis.
Respiratory acidosis (hypercapnia) is a condition caused by insufficient elimination of CO2 from the body during hypoventilation. Laboratory tests show:
pH<7,35,
pCO2a > 46 mm Hg
BE – normal values
However when the respiratory acidosis progresses renal compensation fails to maintaiormal values and BE gradually increases. In order to improve this condition you should treat acute and chronic respiratory violations. When pCO2 is over 60 mm Hg begin artificial lung ventilation (through the mask or tube; when the necessity of ventilation lasts longer than 3 days – perform tracheostomy).
Respiratory alkalosis (hypocapnia) is usually an effect of hyperventilation, caused by excessive stimulation of respiratory centre (injuries, metabolic acidosis, hyperactive metabolism, etc.) or wrong parameters of mechanical ventilation. Gasometry shows:
pH>7,45,
pCO2a <33 mm Hg
BE < +1,5 mmol/l.
However prolong alkalosis brings decrease of BE due to compensatory retain of H+ ions. To improve this imbalance treat its reason: normalize ventilation parameters; if patients breathing has rate over 40 per minute – sedate the patient, perform the intubation and begin artificial ventilation with normal parameters.
Metabolic acidosis is characterized with absolute and relative increase of H+ ions concentration due to acid accumulation (metabolic disorders, block of acid elimination, excessive acid consumption in case of poisonings, etc.). Laboratory tests show:
pH<7,35,
pCO2a < 35 mm Hg
BE (-3) mmol/l.
Treat the main reason of acid-base disorder: diabetic ketoacidosis, renal insufficiency, poisoning, hyponatremia or hyperchloremia, etc. Normalize pH with 4% sodium bicarbonate solution. Its dose is calculated according to the formula:
V=0,3*BE*BW
V- volume of sodium bicarbonate solution, ml
BE – bases excess with “-”, mmol/l
BW – body weight, kg
Metabolic alkalosis is a condition of absolute and relative decrease of H+ ions concentration. Blood tests show:
pH>7,45,
pCO2a normal or insignificantly increased (compensatory reaction)
BE 3,0 mmol/l.
To treat this condition use “acid” solutions, which contain chlorides (saline, potassium chloride). In case of kaliopenia give potassium solutions.
Respiratory and metabolic imbalances can mix in case of severe decompensated diseases due to failure of compensatory mechanisms. Correct interpretation of these violations is possible only in case of regular and iterative gasometry blood tests.
Control tasks.
Task 1.
Calculate the total body water volume and its extracellular and intracellular volumes of the Patience, the patient of 48 years and body weight 88 kg.
Task 2.
Patience, the patient of 23 with body weight 70 kg has sodium level 152 mmol/l and hematocrit 0,49 l/l. Name the type of water balance disorder.
Task 3.
Patience, the patient of 54 with body weight 76 kg has sodium level 128 mmol/l. Calculate the volume of saline and 7,5% sodium chloride solutioecessary for the treatment of this condition.
Task 4.
Patience, the patient of 60 with body weight 60 kg has sodium level 140 mmol/l and hematocrit 0,55 l/l. Name the type of disorder and prescribe infusion therapy.
Task 5.
Patience, the patient of 42 with body weight 80 kg has potassium level 2,6 mmol/l. Calculate the volume of 4% potassium chloride solutioecessary for treatment of this condition.
Task 6.
Patience, the patient of 33 with body weight 67 kg and diagnosis “gastric ulcer, complicated with pylorostenosis” has potassium concentration 3 mmol/l, chlorine concentration 88 mmol/l. pH 7,49, pCO2a 42 mm Hg, BE + 10 mmol/l. Name the type of disorder.
Task 7.
Patience, the patient of 50 with body weight 75 kg, was transported to the admission unit of the hospital with: unconsciousness, cyanotic skin, low blood pressure, shallow breathing. Blood tests show: pH 7,18, pCO2a 78 mm Hg, pO2A – 57 mm Hg, BE -4,2 mmol/l. Name the type of acid-base disorder and prescribe treatment.
Task 8.
Patience, the patient with body weight 62 kg and renal insufficiency has: potassium concentration 5,2 mmol/l, sodium concentration 130 mmol/l, calcium concentration 1,5 mmol/l, pH 7,22, pCO2a 34 mm Hg, BE -9,2 mmol/l. Name the type of disorder.
Violations of homoeostasis and their correction.
9.1 The importance of the water to the organism.
Life on earth was born in the water environment. Water is a universal solvent for all the biochemical processes of the organism. Only in case of stable quantitative and qualitative composition of both intracellular and extra cellular fluids homoeostasis is remained.
The body of an adult human contains 60% of water. Intracellular water makes 40% of the body weight, the water of intercellular space makes 15% of body weight and 5% of body weight are made by the water in the vessels. It is considered that due to unlimited diffusion of water between vessels and extra vascular space the volume of extracellular fluid is 20% of body weight (15%+5%).
Physiologically insignificant amounts of water are distributed beyond the tissues in the body cavities: gastrointestinal tract, cerebral ventricles, joint capsules (nearly 1% of the body weight). However during different pathologic conditions this “third space” can cumulate large amounts of fluid: for example in case of ascites caused by chronic cardiac insufficiency or cirrhosis abdominal cavity contains up to 10 liters of fluid. Peritonitis and intestinal obstructions remove the fluid part of blood from the vessels into the intestinal cavity.
Severe dehydration is extremely dangerous for the patient. Water gets to the body with food and drinks, being absorbed by the mucous membranes of gastro-intestinal tract in total amount of 2-3 liters per day. Additionally in different metabolic transformations of lipids, carbohydrates and proteins nearly 300 of endogenous water are created. Water is evacuated from the body with urine (1,5-
Water balance is regulated through complicated, but reliable mechanisms. Control over water and electrolytes excretion is realized by osmotic receptors of posterior hypothalamus, volume receptors of the atrial walls, baroreceptors of carotid sinus, juxtaglomerular apparatus of the kidneys and adrenal cortical cells.
When there is a water deficiency or electrolytes excess (sodium, chlorine) thirst appears and this makes us drink water. At the same time posterior pituitary produces antidiuretic hormone, which decreases urine output. Adrenals reveal into the blood flow aldosterone, which stimulates reabsorption of sodium ions in the tubules and thus also decreases diuresis (due to osmosis laws water will move to the more concentrated solution). This way organism can keep precious water.
On the contrary, in case of water excess endocrine activity of glands is inhibited and water is actively removed from the body through the kidneys.
9.2 Importance of osmolarity for homoeostasis.
Water sections of the organism (intracellular and extracellular) are divided with semipermeable membrane – cell wall. Water easily penetrates through it according to the laws of osmosis. Osmosis is a movement of water through a partially permeable membrane from the solution with lower concentration to a solution with higher concentration.
Osmotic concentration (osmolarity) is the concentration of active parts in one liter of solution (water). It is defined as a number of miliosmoles per liter (mOsm/l). Normally osmotic concentration of plasma, intracellular and extracellular fluids is equal and varies between 285mOsm/l. This value is one of the most important constants of the organism, because if it changes in one sector the whole fluid of the body will be redistributed (water will move to the environment with higher concentration). Over hydration of one sector will bring dehydration of another. For example, when there is a tissue damage concentration of active osmotic parts increases and water diffuses to this compartment, causing oedema. On the contrary plasma osmolarity decreases, when there is a loss of electrolytes and osmotic concentration of the cellular fluid stays on the previous level. This brings cellular oedema, because water moves through the intracellular space to the cells due to their higher osmotic concentration.
Cerebral oedema appears when the plasma osmolarity is lower than 270 mOsm/l. Activity of central nervous system is violated and hypoosmolar coma occurs. Hyperosmolar coma appears when the plasma osmolarity is over 320 mOsm/l: water leaves the cells and fills the vascular bed and this leads to cellular dehydration. The sensitive to cellular dehydration are the cells of the brain.
Plasma osmolarity is measured with osmometer. The principle of measurement is based on difference in freezing temperature between distillated water and plasma. The higher is the osmolarity (quantity of molecules) the lower is freezing temperature.
Plasma osmotic concentration can be calculated according to the formula:
Osmotic concentration= 1,86*Na+glucose+urea+10,
Plasma osmolarity (osmotic concentration) – mOsm/l
Na- sodium concentration of plasma, mmol/l
Glucose- glucose concentration of the plasma, mmol/l
Urea- urea concentration of the plasma, mmol/l
According to this formula sodium concentration is the main factor influencing plasma osmolarity. Normally sodium concentration is 136-144 mmol/l. Water and electrolytes balance can be violated with external fluid and electrolytes loss, their excessive inflow or wrong distribution.
9.3 Fluid imbalance and principles of its intensive treatment.
Water imbalance is divided into dehydration and overhydration.
Dehydration is caused by:
– excessive perspiration in conditions of high temperature;
– rapid breathing (dyspnea, tachypnea) or artificial ventilation without humidification of the air;
– vomiting, diarrhoea, fistulas;
– blood loss, burns;
– diuretics overdose;
– excessive urine output;
– inadequate enteral and parenteral nutrition or infusion therapy (comatose patients, postoperative care);
– pathological water distribution (“third space” in case of inflammation or injury).
Dehydration signs: weight loss, decrease of skin turgor and eyeballs tone, dry skin and mucous membranes; low central venous pressure, cardiac output and blood pressure (collapse is possible); decreased urine output and peripheral veins tone; capillary refill over 2 seconds (microcirculation disorders) and low skin temperature; intracellular dehydration is characterized with thirst and consciousness disorders. Laboratory tests show blood concentration: hematocrit, hemoglobin concentration, protein level and red blood cells concentration increase.
Overhydration appears in case of:
– excessive water consumption, inadequate infusion therapy;
– acute and chronic renal failure, hepatic and cardiac insufficiency;
– disorders of fluid balance regulation;
– low protein edema.
Clinical findings in case of overhydration are: weight gain, peripheral oedema, transudation of the plasma into the body cavities (pleural, abdominal), high blood pressure and central venous pressure. In case of intracellular overhydration appear additional symptoms: nausea, vomiting, signs of cerebral edema (spoor, coma). Laboratory tests prove hemodilution.
According to the osmotic concentration of plasma dehydration and overhydration are divided into hypotonic, isotonic and hypertonic.
Isotonic dehydration is caused by equal loss of electrolytes and fluid from the extracellular space (without cellular disorders).Blood tests show hemoconcentration; sodium level and osmotic concentration are normal.
To treat this type of water imbalance use normal saline solution, Ringer solution, glucose-saline solutions, etc.. The volumes of infusions can be calculated according to the formula:
VH2O= 0,2*BW* (Htp-0,4)/0,4 ,
VH2O – volume of infusion, l
Htp – patient’s hematocrit, l/l,
BW – body weight, 0,2*BW – volume of extracellular fluid,
0,4- normal hematocrit, l/l,
Hypertonic dehydration is caused by mostly water loss: first it appears in the vascular bed, than in the cells. Laboratory tests show hemoconcentration: elevated levels of proteins, red blood cells, hematocrit. Plasma sodium is over 155 mmol/l and osmotic concentration increases over 310 mOsm/l.
Intensive treatment: if there is no vomiting allow patients to drink. Intravenously give 0,45% saline solution and 2,5 % glucose solution, mixed with insulin. The volume of infusions is calculated according to the formula:
VH2O=0,6*BW (Nap -140)/140,
VH2O – water deficiency, l
Nap – plasma sodium, mmol/l
BW – body weight, 0,6*BW volume of general body fluid
140 – physiological plasma sodium concentration
Hypotonic dehydration is characterized with clinical features of extracellular dehydration. Laboratory tests show decrease of sodium and chlorine ions. Those changes cause intracellular movement of the water (intracellular overhydration). Hemoglobin, hematocrit and protein levels are increased. Sodium is lower than 136 mmol/l, osmolarity is lower than 280 mOsm/l.
To treat this type of water imbalance use normal or hypertonic saline and sodium bicarbonate solution (depends on blood pH). Do not use glucose solutions!
The deficiency of electrolytes is calculated according to the formula:
Nad = (140-Nap)*0,2 BW,
Nad – sodium deficiency, mmol
Nap – plasma sodium, mmol/l
BW – body weight, 0,2 BW – volume of extracellular fluid
Isotonic overhydration is caused by excess of the water in the vascular bed and extracellular space; however intracellular homoeostasis is not violated. Hemoglobin is less than 120 g/l, protein level is less than 60 g/l, plasma sodium is 136-144 mmol/l, osmotic concentration is 285-310 mOsm/l.
Treat the reason of imbalance: cardiac failure, liver insufficiency, etc. Prescribe cardiac glycosides, limit salt and water consumption. Give osmotic diuretics (mannitol solution 1,5 g/kg), saluretics (furosemide solution 2 mg/kg), aldosterone antagonists (triamterene – 200 mg), steroids (prednisolone solution 1-2 mg/kg) albumin solution if necessary (0,2-0,3 g/kg).
Hypertonic overhydration is a state of extracellular electrolytes and water excess combined with intracellular dehydration. Blood tests show decrease of hemoglobin, hematocrit, protein level, however sodium concentration is increased over 144 mmol/l, osmotic concentration is over 310 mOsm/l.
To treat this condition use solutions without electrolytes: glucose with insulin, albumin solutions and prescribe saluretics (furosemide solution), aldosterone antagonists (spironolactone). If it is necessary perform dialysis and peritoneal dialysis. Do not use crystalloids!
Hypotonic overhydration is a state of extracellular and intracellular water excess. Blood tests show decrease of haemoglobin, hematocrit, proteins, sodium and osmotic concentration. Intensive therapy of this condition includes osmotic diuretics (200-400 ml of 20% mannitol solution), hypertonic solutions (50 ml of 10% saline intravenously), steroids. When it is required use ultrafiltration to remove water excess.
9.4 Electrolytes disorders and their treatment
Potassium is a main intracellular cation. Its normal plasma concentration is 3,8-5,1 mmol/l. Daily required amount of potassium is 1 mmol/kg of body weight.
Potassium level less than 3,8 mmol/l is known as kaliopenia. Potassium deficiency is calculated according to the formula:
Kd= (4,5-Kp)*0,6 BW
K- potassium deficiency, mmol;
Kp – potassium level of the patient mmol/l;
0,6*BW – total body water, l.
To treat this state use 7,5% solution of potassium chloride (1ml of this solution contains 1 mmol of potassium). Give it intravenously slowly with glucose and insulin (20-25 ml/hour). You can also prescribe magnesium preparations. Standard solution for kaliopenia treatment is:
10% glucose solution 400 ml
7,5% potassium chloride solution 20 ml
25% magnesium sulphate solution 3 ml
insulin 12 units
Give it intravenously slowly, during one hour. Forced bolus infusion of potassium solutions (10-15 ml) can bring cardiac arrest.
Potassium level over 5,2 mmol/l is a state called hyperkalemia. To treat this condition use calcium gluconate or calcium chloride solutions (10 ml of 10% solution intravenously), glucose and insulin solution, saluretics, steroids, sodium bicarbonate solution. Hyperkalemia over 7 mmol/l is an absolute indication for dialysis.
Sodium is the main extracellular cation. Its normal plasma concentration is 135-155 mmol/l. Daily required amount of potassium is 2 mmol/kg of body weight.
Sodium concentration which is lower than 135 mmol/l is known as hyponatraemia. This condition is caused by sodium deficiency or water excess. Sodium deficiency is calculated according to the formula:
Nad= (140-Nap)*0,2 BW,
Na- sodium deficiency, mmol;
Nap – sodium concentration of the patient mmol/l;
0,2*BW – extracellular fluid volume, l.
To treat it use normal saline (1000 ml contains 154 Na mmol) or 5,8% solution of sodium chloride – your choice will depend on osmotic concentration.
Sodium concentration over 155 mmol/l is a state called hypernatremia. This condition usually appears in case of hypertonic dehydration or hypertonic overhydration. Treatment was described in the text above.
Chlorine is the main extracellular anion. Its normal plasma concentration is 98-107 mmol/l. Daily requirement of chlorine is 215 mmol.
Hypochloremia is a condition of decreased plasma chlorine concentration (less than 98 mmol/l).
Chlorine deficiency is calculated according to the formula:
Cld = (100-Clp)*0,2 BW,
Cld- chlorine deficiency, mmol
Clp – plasma chlorine concentration of the patient, mmol/l
0,2*BW – extracellular fluid volume, l.
To treat hypochloremia use normal saline (1000 ml contains 154 mmol of chlorine) or 5,8% sodium chlorine solution (1 ml contains 1 mmol of chlorine). The choice of solution depends on the osmotic concentration of the plasma.
Hyperchloremia is a condition of increased chlorine concentration (over 107 mmol/l). Intensive therapy of this state includes treatment of the disease, which caused it (decompensated heart failure, hyperchloremic diabetes insipidus, glomerulonephritis). You can also use glucose, albumin solutions and dialysis.
Magnesium is mostly an intracellular cation. Its plasma concentration is 0,8-1,5 mmol/l. Daily requirement of magnesium is 0,3 mmol/kg.
Hypomagnesemia is a state of decreased magnesium concentration: less than 0,8 mmol/l. Magnesium deficiency is calculated according to the formula:
Mgd =(1,0 – Mgp)*0,6BW,
Mgd – magnesium deficiency, mmol
Mgp – plasma magnesium concentration of the patient, mmol/l
0,6*BW – extracellular fluid volume, l.
Use 25% magnesium sulphate solution to treat this state (1 ml of it contains 0,5 mmol of magnesium).
Hypermagnesemia is a state of increased magnesium concentration (more than 1,5 mmol/l). This condition appears usually in case of hyperkalemia and you should treat it as you treat hyperkalemia.
Calcium is one of the extracellular cations. Its normal concentration is 2,35-2,75 mmol/l. Daily requirement of calcium is 0,5 mmol/kg.
Calcium concentration less than 2,35 mmol/l is called hypocalcemia. Calcium deficiency is calculated according to the formula:
Cad = (2,5-Cap)*0,2 BW,
Cad – calcium deficiency, mmol
Clp – plasma calcium concentration of the patient, mmol/l
0,2*BW – extracellular fluid volume, l.
To treat this state use 10% calcium chloride (1 ml of the solution contains 1,1 mmol of calcium), ergocalciferol; in case of convulsions prescribe sedative medicines.
Hypercalcemia is a condition with increased calcium concentration (over 2,75 mmol/l). Treat the disease, which caused it: primary hyperparathyroidism, malignant bone tumors, etc. Additionally use infusion therapy (solutions of glucose with insulin), steroids, dialysis and hemosorbtion.
9.5 Acid-base imbalance and its treatment.
There are 2 main types of acid-base imbalance: acidosis and alkalosis.
pH is a decimal logarithm of the reciprocal of the hydrogen ion activity. It shows acid-base state of the blood.
Normal pH of arterial blood is 7,36-7,44. Acid based imbalance is divided according to the pH level into:
pH 7,35-7,21 – subcompensated acidosis
pH < 7,2 – decompensated acidosis
pH 7,45-7,55 – subcompansated alkalosis
pH > 7,56 – decompensated alkalosis
Respiratory part of the acid-base imbalance is characterized with pCO2. Normally pCO2 of arterial blood is 36-44 mm Hg. Hypercapnia (pCO2 increased over45 mm Hg) is a sign of respiratory acidosis. Hypocapnia (pCO2 less than 35 mm Hg) is a symptom of respiratory alkalosis.
Basis excess index is also a characteristic of metabolic processes. Normally H+ ions produced during metabolic reactions are neutralized with buffer system. BE of arterial blood is 0±1,5. Positive value of BE (with +) is a sign of base excess or plasma acid deficiency (metabolic alkalosis). Negative value of BE (with -) is a symptom of bases deficiency, which is caused by acid neutralization in case of metabolic acidosis.
Respiratory acidosis (hypercapnia) is a condition caused by insufficient elimination of CO2 from the body during hypoventilation. Laboratory tests show:
pH<7,35,
pCO2a > 46 mm Hg
BE – normal values
However when the respiratory acidosis progresses renal compensation fails to maintaiormal values and BE gradually increases. In order to improve this condition you should treat acute and chronic respiratory violations. When pCO2 is over 60 mm Hg begin artificial lung ventilation (through the mask or tube; when the necessity of ventilation lasts longer than 3 days – perform tracheostomy).
Respiratory alkalosis (hypocapnia) is usually an effect of hyperventilation, caused by excessive stimulation of respiratory centre (injuries, metabolic acidosis, hyperactive metabolism, etc.) or wrong parameters of mechanical ventilation. Gasometry shows:
pH>7,45,
pCO2a <33 mm Hg
BE < +1,5 mmol/l.
However prolong alkalosis brings decrease of BE due to compensatory retain of H+ ions. To improve this imbalance treat its reason: normalize ventilation parameters; if patients breathing has rate over 40 per minute – sedate the patient, perform the intubation and begin artificial ventilation with normal parameters.
Metabolic acidosis is characterized with absolute and relative increase of H+ ions concentration due to acid accumulation (metabolic disorders, block of acid elimination, excessive acid consumption in case of poisonings, etc.). Laboratory tests show:
pH<7,35,
pCO2a < 35 mm Hg
BE (-3) mmol/l.
Treat the main reason of acid-base disorder: diabetic ketoacidosis, renal insufficiency, poisoning, hyponatremia or hyperchloremia, etc. Normalize pH with 4% sodium bicarbonate solution. Its dose is calculated according to the formula:
V=0,3*BE*BW
V- volume of sodium bicarbonate solution, ml
BE – bases excess with “-”, mmol/l
BW – body weight, kg
Metabolic alkalosis is a condition of absolute and relative decrease of H+ ions concentration. Blood tests show:
pH>7,45,
pCO2a normal or insignificantly increased (compensatory reaction)
BE 3,0 mmol/l.
To treat this condition use “acid” solutions, which contain chlorides (saline, potassium chloride). In case of kaliopenia give potassium solutions.
Respiratory and metabolic imbalances can mix in case of severe decompensated diseases due to failure of compensatory mechanisms. Correct interpretation of these violations is possible only in case of regular and iterative gasometry blood tests.
