An inhalation worm. The induction of anesthesia, and especially the awakening, take place quickly. Over-production of saliva and tracheal-bronchial secretions does not occur, and the throat reflex and laryngeal reflex are quickly suppressed. Using isoflurane, you can quickly change the depth of anesthesia. The heart rhythm does not change, and with the deepening of general anesthesia the inhibition of spontaneous respiratory function increases. During induction, there is generally a reduction in blood pressure, which returns to normal as a result of stimulation due to surgery. In the maintenance phase of anesthesia, the blood pressure decreases proportionally to the depth of anesthesia, but the heart rhythm does not change. In the case of a controlled breath and a correct pCO value2, the cardiac output is generally kept constant despite the deepening of the anesthesia, mainly by the acceleration of cardiac function, which compensates for the reduction in cardiac output. In the case of spontaneous respiration, hypercapnia develops, which may accelerate cardiac function and increase the minute capacity above the values observed in the waking state. The cerebral flow does not change during shallow anesthesia with isoflurane, but generally increases in the case of deeper anesthesia. Isoflurane sensitizes the heart muscle to adrenaline to an even lesser extent than enflurane. Isoflurane is subject to relatively small metabolic changes in the body. In the postoperative period, only 0.17% of the administered dose is excreted in the urine as metabolites. The maximum concentration of inorganic fluoride in the serum is on average less than 5 μM / l and occurs about 4 hours after anesthesia, reaching normal values within 24 hours. No toxicity of isoflurane to the kidneys was found.
Contraindications:
Hypersensitivity to isoflurane or other halogen inhalational anesthetics. Diagnosis or suspicion of genetically determined malignant hyperthermia.
Precautions:
Isoflurane may cause liver damage (in very rare cases, hepatic necrosis), the risk increases when exposed to inhaled halogen general anesthesia at intervals of less than 3 months. In patients with coronary heart disease, due to the "coronary steal syndrome", it is necessary to maintain normal hemodynamic parameters in order to avoid myocardial ischemia. Caution should be exercised in patients with elevated intracranial pressure (hyperventilation may be necessary). Isoflurane significantly increases the effect of non-depolarizing muscle relaxants. In genetically predisposed patients, anesthesia with the preparation may trigger increased skeletal muscle metabolism leading to an increased need for oxygen and a set of clinical symptoms called malignant hyperthermia (discontinuation of isoflurane, intravenous dantrolene sodium and treatment of vital signs to restore normal body temperature, support breathing and circulation, and compensate for fluid-electrolyte and acid-base balance disorders, kidney failure should be monitored and diuresis should be maintained). Caution should be exercised in patients with latent and overt neuromuscular disease, especially Duchenne dystrophy, due to the risk of increased serum potassium after the use of inhaled anesthetics, which may lead to arrhythmia and death. These patients may also experience a significant increase in creatine kinase in the blood and changes indicating myoglobinuria - early and vigorous intervention is recommended to compensate for hyperkalemia and treatment of persistent arrhythmias, and then to study for latent neuromuscular disease. As the depth of anesthesia increases, blood hypotension and respiratory depression intensify. In patients undergoing curettage of the uterine cavity, increased blood loss was observed.A transient prolonged appearance of BSP in the bromosulfphthalein trial and an increase in serum Glucose and serum creatinine with decreases in urea nitrogen, cholesterol and alkaline phosphatase were observed during treatment.
Pregnancy and lactation:
It has not been established whether use of isoflurane during pregnancy is safe, but there is no reason to suspect that the drug used for anesthesia during pregnancy has any specific side effects. After the abortion procedure, a blood loss comparable to that observed after anesthesia with other inhalants was observed. It was shown that isoflurane in a concentration of not more than 0.75% is a safe and effective means to maintain anesthesia in caesarean section. In mothers and newborns, no adverse effects resulting from the use of the drug were found. Caution should be exercised when administering isoflurane to breast-feeding women. It is not known whether the drug is excreted in breast milk.
Side effects:
Side effects of the drug depend on its dose and include respiratory depression, hypotension and cardiac arrhythmias. In the postoperative period, chills, nausea, vomiting and intestinal obstruction were observed. In addition, transient increase in the number of white blood cells, even in the absence of stress resulting from surgery. With simultaneous administration of nitrous oxide in adults, the MAC value is reduced. Hypersensitivity has been rarely reported (including contact dermatitis, rash, shortness of breath, wheezing, chest discomfort, facial edema or anaphylaxis). In very rare cases, liver damage may occur, from slight, transient increases in liver enzymes to hepatic necrosis.
Dosage:
The medicine can only be administered in hospital wards equipped with adequate anesthetic equipment by personnel with appropriate training and experience in dealing with patients undergoing anesthesia. For dosages of isoflurane, specially calibrated evaporators should be used to precisely control the concentration of the administered agent of general anesthesia. Induction of anesthesia: initially 0.5% vol., Then 1.5-3.0% vol. Maintenance of anesthesia: 1-2.5% vol. in a mixture of oxygen / nitrous oxide or 1.5-3.5% by volume with pure oxygen; if additional muscle relaxation is necessary, you can additionally use a muscle relaxant. Minimum alveolar concentrations (MAC) change with age: newborns -1,6%, infants 1-6 months. - 1.87%, infants 6-12 months - 1.8%; adults aged 26 +/- 4 - 1.28%, 44 +/- 7 - 1.15%, 64 +/- 5 - 1.05% (values in pure oxygen are given). Elderly patients are advised to lower isoflurane to maintain anesthesia for surgery.
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