Complications of anesthesia are unintended negative effects that occur during general anesthesia or shortly after waking up. They manifest themselves in the form of respiratory failure, circulatory disorders, excessive central nervous system depression, vomiting, regurgitation. After awakening, psychoses, hallucinatory syndrome, paresis and paralysis may develop. In some cases, dynamic intestinal obstruction is detected. The diagnosis is established on the basis of clinical signs, data from hardware monitoring of vital functions, laboratory examination of biological environments of the body.
Complications of anesthesia belong to the category of iatrogenic conditions resulting from the actions of a medical professional. Most often they are preventable with a sufficient amount of preventive measures and careful preparation of the anesthesiologist for surgery. The number of unforeseen problems is decreasing every year. According to data for 1956, the mortality rate for reasons related to general anesthesia reached 15%. Today, this indicator does not exceed 0.02% when using the endotracheal method of feeding the mixture, modern anesthetics, continuous monitoring of the patient’s condition. The number of non-lethal problems, according to statistics for 2014, reaches 2.5%.
The absolute majority of problems that arise during anesthesia are caused by the wrong actions of an anesthesiologist or an anesthesiologist nurse. Complications of anesthesia may also be caused by a violation of the doctor’s recommendations on the part of the patient. The manifestation of allergic reactions, which cannot be foreseen, occurs only in 1% of cases of the total number of life-threatening pathology. Even less often, malignant hyperthermia is diagnosed – a condition of muscular hypermetabolism that develops as a reaction to the introduction of depolarizing muscle relaxants. The causes of pathology are more convenient to consider by body systems:
- Hypoventilation. The main complications of endotracheal anesthesia: disconnection or bending of the contours, incorrect ratio of the air-gas mixture, violation of calibration or mechanical malfunction of the device, the development of respiratory metabolic failures. In addition to the above, the accumulation of sputum in the intubation tube in the absence of aspiration leads to insufficient oxygen supply to the body. If the patient is not on a ventilator, respiratory arrest is possible with an overdose of an anesthetic substance.
- Hemodynamic disorders. Occur in patients with chronic heart disease, suffering from hypertension or hypotension. All these factors should be identified and adjusted as far as possible before intervention. Insufficient examination is the cause of severe processes up to shock and death of the patient. A decrease in blood pressure and cardiac arrhythmias also occur with primary coronary weakness, violation of normal vascular tone, a decrease in CBV caused by blood loss.
- Oppression of the central nervous system. It is found mainly with the wrong selection of the dose of the drug. Patients who need a mixture with a reduced amount of anesthetic suffer. In case of overdose, the patient is immersed in the III3 or III4 stage of anesthesia. The cause of complications of this kind is the mistake of the anesthesiologist in choosing the dosage of the drug.
- Violation of the bowel. The most common type of such failures is vomiting. Occurs as a result of irritation of the emetic center by the absorbed agent. To prevent this, the patient is recommended to refuse to eat 8-12 hours before the start of anesthesia. Emergency patients are washed out of the stomach. The causes of vomiting that occurs during the intervention are non–compliance with medical recommendations, inattention of the anesthesiologist who did not warn the patient about food restrictions, insufficient quality gastric lavage before the operation.
The mechanism of development depends on the type of complication of anesthesia. Hypoventilation causes hypoxia and hypercapnia, metabolic processes in the tissues of the body are disrupted, respiratory acidosis occurs. There is a disorder of vital reactions. With a critical decrease in blood pressure, a state of shock develops, the centralization of blood circulation, tissue perfusion decreases, the supply of organs and systems with oxygen and nutrients. Against the background of circulatory insufficiency, reversible and then irreversible changes occur in the structure of the tissues of the central nervous system.
With excessive depression of the central nervous system, malfunctions occur in the regulation of the work of internal organs, including the heart, lungs, liver, kidneys. Vomiting is the result of irritation of the corresponding center. With the endotracheal method of giving an anesthetic, it does not pose a significant danger. If the patient is breathing independently, there is a risk of aspiration of vomit. Complications of aspiration are pneumonia, damage to the trachea and bronchi by acidic gastric contents.
The division of all possible complications is carried out according to the signs of a lesion of a particular system. It is customary to distinguish 5 main groups, each of which includes several varieties of pathological conditions. The most dangerous damage to the respiratory system and circulatory system. There are the following types of negative reactions occurring during or after general anesthesia:
- Defeat of the respiratory organs. Occurs most often. It manifests itself in the form of mechanical asphyxia with tongue sinking, laryngospasm, obstruction of the respiratory tract by vomit, sputum, blood. With intravenous anesthesia without intubation, it is possible to block the respiratory center against the background of exceeding the permissible dose of medications or an individual reaction.
- Defeat of the circulatory system. The main manifestations are tachycardia, extrasystole, atrial or ventricular fibrillation. It is possible to develop acute heart failure, in which the heart ceases to cope with the load. Changes in vascular tone lead to hypotension or hypertension, may be complicated by compensatory reactions, in particular – tachyarrhythmia, myocardial infarction.
- Defeat of the central nervous system. Deep brain damage is accompanied by depression of independent breathing, excessive immersion in anesthesia, which complicates the exit from it. With neurogenic circulatory disorders, the brain undergoes hypoxia, which subsequently provokes posthypoxic encephalopathy. The specific effects of some drugs are delirium, hallucinations, psychomotor agitation at the stage of immersion in or out of anesthesia, muscle hyperreactivity. They occur when using ketamine, propofol, and inhaled anesthetics.
- Gastrointestinal tract damage. Symptoms are vomiting, postoperative intestinal paresis. Vomiting is easily stopped by the introduction of antiemetics. With paresis, constipation develops, complex therapeutic measures are required. Paresis is most often observed after operations on the intestine, in which mechanical and drug-induced negative effects on the digestive system are combined.
- Allergic reactions. Complications of this type are not considered iatrogenic, belong to the group of unforeseen incidents. They may manifest in the form of urticaria (a red rash raised above the skin level), angioedema of the respiratory tract or other parts of the patient’s body, anaphylactic shock. The latter is the most severe reaction to contact with the trigger factor, in the absence of timely diagnosis often leads to the death of the patient.
Respiratory disorders manifest themselves in the form of classic signs of hypoxia. Diffuse cyanosis is detected, compensatory tachycardia, possibly an increase in blood pressure. SpO2 decreases, hypercapnia increases. When sputum accumulates, wheezing and gurgling are heard. The equipment signals insufficient airway patency. The volume of inspiration decreases. Complications of anesthesia caused by damage to the cardiovascular system lead to an increase or decrease in the pulse rate above 90 or below 60 beats per minute, respectively. When the AD falls, the skin is pale, covered with cold sticky sweat, the mucous membranes are bluish in color. Increased pressure in the vessels can be accompanied by both hyperemia and pallor of the skin, occurs with reflex spasm of capillaries.
The defeat during surgery includes violations of hemodynamics, heart rhythm. The awakening is delayed. Consciousness is restored for a long time, often not completely. Less severe reversible failures are diagnosed by the presence of hallucinosis, inappropriate behavior. The patient does not understand where he is, what happened to him, swears obscenely. There is no critical assessment of actions. The normal state is restored within a few hours. Symptoms of gastrointestinal tract damage include vomiting, nausea, constipation or diarrhea, absence of intestinal noises during auscultation.
Complications of anesthesia are detected by the anesthesiologist leading the patient. To do this, a preoperative and postoperative examination is carried out. During the intervention, the doctor is constantly at the head of the patient, observing his condition and taking measures to correct the emerging disorders. The diagnosis is made based on clinical signs and monitoring results. The severity of the existing failures and the features of their course are determined by the information obtained by laboratory methods. The list of diagnostic measures includes:
- Physical examination. Specific signs of a particular violation are revealed. Auscultation allows you to detect extraneous noises and wheezing in the lungs during sputum aspiration, “dumb” areas when the airways are blocked. During the operation, the patient’s chest excursion is visually monitored. Its termination indicates a critically low intake of air.
- Hardware inspection. The main method is to connect the patient to a heart monitor for the entire duration of the intervention. Parameters such as blood pressure, percentage of oxygen saturation, heart rate, body temperature are measured. An increase or decrease in blood pressure, an uneven pulse are symptoms of hemodynamic disorders, a decrease in SpO2 in combination with tachycardia are manifestations of respiratory failure. Brain damage is determined by electroencephalography by the weakening or complete absence of signs of activity. Uncontrolled increase in body temperature suggests the development of malignant hyperthermia. Intestinal paresis is diagnosed at the postoperative stage using abdominal ultrasound (absence of peristalsis).
- Laboratory examination. Is auxiliary. With hypoxia, a decrease in pH less than 7.35 is detected, an increase in the concentration of carbon dioxide. Acute myocardial infarction leads to an increase in troponins, LDH, CFK, CFK MV. With HR, products of destruction of striated musculature appear in the blood.
Therapy is carried out taking into account the causes that caused the pathological condition. In case of respiratory disorders, the composition and volume of the gas-air mixture are adjusted, the endotracheal tube is sanitized using an electric pump. If it is not possible to completely clear the airways, call the on-duty endoscopic team for an emergency bronchoscopy. Narcotic analgesics, atropine, antispasmodics, and adrenomimetics are used to relieve laryngospasm. To saturate the blood with O2, the device is put into the mode of enhanced oxygenation (100%). Maintaining a sleepy state is provided by intravenous anesthetics.
Disorders from the CVS are treated asymptomatically. When bradycardia requires the introduction of atropine, adrenaline. A decrease in blood pressure against the background of weakening of cardiac activity is an indication for transferring a patient to the introduction of pressor amines through a syringe pump. It may be necessary to reduce the dose of anesthetic. Arrhythmias are stopped using cordarone, amiodarone, novocainamide, lidocaine. Fibrillation, which is not amenable to chemical action, requires electrical defibrillation. With an increase in blood pressure, antihypertensive drugs are administered, with a decrease – hypotonic drugs, infusion solutions to replenish CBV, steroid hormones.
Relief of short-term postoperative psychoses with medications is not performed. With pronounced psychomotor agitation, the appointment of neuroleptics, narcotic analgesics is allowed. Long-term disorders of the central nervous system require therapy with the use of nootropics, antioxidants, tonic agents (multivitamin complexes, adaptogens). Intestinal tone usually recovers on its own in 1-2 days. With a prolonged course of paresis, proserin is injected.
Malignant hyperthermia is an indication for the administration of datrolene, a muscle relaxant capable of blocking ryanodine receptors. In addition, prescribe medications for symptomatic treatment, physical ways to reduce the temperature (ice on large vessels, wetting the sheets and the patient’s body with cold water, ventilation or). In case of allergic reactions, antihistamines, glucocorticosteroids, symptomatic medications are injected. Severe manifestations require mandatory tracheal intubation, transfer to a ventilator, if this has not been done before.
Prognosis and prevention
The prognosis for complications of anesthesia is favorable if they are detected in a timely manner. Therapeutic measures allow to stop the phenomena of respiratory and cardiovascular insufficiency without delayed consequences. Long-term hypoxia (posthypoxic encephalopathy or brain death), myocardial ischemia (MI) leads to irreversible changes. Inhalation of vomit can have severe consequences in the form of aspiration pneumonia. In the absence of help, the prognosis is unfavorable. The patient’s death occurs from suffocation, atrial fibrillation, shock.
Complications of anesthesia can be prevented with careful collection of anamnesis. The specialist finds out whether the patient or his relatives have had allergic reactions to anesthetics, episodes of malignant hyperthermia. The patient is informed about the ban on eating any food 10 hours before admission to the operating room. During anesthesia, the anesthesiologist maintains adequate ventilation of the patient’s lungs, the depth of sleep, monitors the main vital signs and the operation of the equipment.