Objective: to provide a rationale for a need to introduce the new constant — the minimum alveolar concentration for respiratory depression (MACrespiratory depression) and to determine its value. Subjects and methods. Forty-three patients aged 20— 45 years, who had normal weight and ASA physical status I—II, were examined. All the patients underwent induction of sevorane anesthesia without narcotic analgesics, nitrous oxide, and myorelaxants. A laryngeal mask was installed after MAClm was achieved. Sevorane concentrations were increased on a vaporizer, by changing Etanesth at a rate of 0.2 vol% per min until Etanesthresp;ratory depression was achieved. Results. A rationale was provided for a need to introduce the new inhalation anesthesia constant MACrespiratory depression that is, in accordance with the MAC conception, regarded as the inhalation anesthetic concentration that necessitates assisted ventilation in 50% of the patients. MACrespiratory depression was 1.8 MAC. This is essentially more than both MAC and 1.3 MAC, the anesthetic concentration at which any operation can be performed in 90% of patients. At the same time, the derived value of 3.7 vol% is somewhat below MACbarr (4.07 vol%), which means that anesthesia with sevorane only under spontaneous respiration will be inadequate in few patients or its performance will be associated with the risk of hypoxia. Conclusion. The authors’ successively developed concept of anesthesia with preserved spontaneous respiration necessitates the introduction of the new inhalation anesthesia constant MACrespiratory depression. Its value is 3.7% vol% for sevoflurane. Key words: induction of anesthesia, minimum alveolar concentration, spontaneous respiration, inhalation anesthesia.

Objective: to optimize anesthetic tactics for perioperative management in elderly patients during lower abdominal surgery under mixed anesthesia with preserved spontaneous breathing without myoplegia. Subjects and methods. Examinations were made in 142 patients aged over 65 years. The patients were divided into 2 groups: 1) inhalation anesthesia under total myoplegia and controlled mechanical ventilation (MV); 2) inhalation anesthesia without myoplegia with preserved spontaneous breathing or assisted mechanical ventilation (AMV) in the pressure-support (PS) mode. Results and discussion. The AMV procedure allows mixed anesthesia with preserved spontaneous breathing in elderly patients during operations on the lower abdomen and great vessels in 89% of the patients without a risk for inadequate transport of oxygen under its relative uptake. MV used to maintain external respiratory function under mixed anesthesia and total myoplegia causes a decrease in cardiac index (CI) by 58.8% (p<0.05) and increases in total peripheral resistance (TPR) by 50% or more (p<0.05), and intrapulmonary shunt threefold (p<0.05). Mixed anesthesia without myoplegia and MV prevents induced changes in CI, TPR, and Qs/Qt. The differences were significant throughout the follow-up (an intraoperative stage and 9 postoperative hours). The older age group patients are more susceptible to the damaging action of MV; they were also found to have a more pronounced preventive effect of modified anesthesia. Conclusion. To rule out myoplegia and MV during mixed anesthesia prevents MV-induced changes in CI, TPR, and Qs/Qt. Key words: mixed anesthesia in elderly patients, spontaneous breathing, hemodynamics, blood oxygen transporting function.

Objective: to provide a rationale for a need to introduce the new constant — the minimum alveolar concentration for respiratory depression (MACrespiratory depression) and to determine its value. Subjects and methods. Forty-three patients aged 20— 45 years, who had normal weight and ASA physical status I—II, were examined. All the patients underwent induction of sevorane anesthesia without narcotic analgesics, nitrous oxide, and myorelaxants. A laryngeal mask was installed after MAClm was achieved. Sevorane concentrations were increased on a vaporizer, by changing Etanesth at a rate of 0.2 vol% per min until Etanesthresp;ratory depression was achieved. Results. A rationale was provided for a need to introduce the new inhalation anesthesia constant MACrespiratory depression that is, in accordance with the MAC conception, regarded as the inhalation anesthetic concentration that necessitates assisted ventilation in 50% of the patients. MACrespiratory depression was 1.8 MAC. This is essentially more than both MAC and 1.3 MAC, the anesthetic concentration at which any operation can be performed in 90% of patients. At the same time, the derived value of 3.7 vol% is somewhat below MACbarr (4.07 vol%), which means that anesthesia with sevorane only under spontaneous respiration will be inadequate in few patients or its performance will be associated with the risk of hypoxia. Conclusion. The authors’ successively developed concept of anesthesia with preserved spontaneous respiration necessitates the introduction of the new inhalation anesthesia constant MACrespiratory depression. Its value is 3.7% vol% for sevoflurane. Key words: induction of anesthesia, minimum alveolar concentration, spontaneous respiration, inhalation anesthesia.

Objective: to improve the results of surgical treatment, by ruling out the negative effects of mechanical ventilation (MV) via combined anesthesia without myoplegia during operations on the lower abdomen. Subjects and methods. One hundred and twenty-one patients aged 20 to 64 years were examined. The patients were divided into 2 groups: 1) inhalation anesthesia under total myoplegia and continuous MV; 2) inhalation anesthesia without myoplegia and with preserved spontaneous respiration or pressure-support MV (PSMV). Results. The procedure of the latter allows combined anesthesia with preserved spontaneous respiration during operations on the lower abdomen and great vessels to have inadequate transport of oxygen under its relatively increased uptake in 98% of patients without any risk. MV made to prosthelytize external respiration function under combined anesthesia and total myoplegia causes a decrease in cardiac index (CI) by 40% or more (p<0.05) and increases in total peripheral vascular resistance (TPVR) by 50% or more (p<0.05) and intrapulmonary shunt by 3 times (p<0.05). Combined anesthesia without myoplegia and MV prevent induced changes in CI, TPVR, and Qs/Qt. The differences are significant throughout the follow-up (an intraoperative step and 9 postoperative hours). Conclusion. To rule out myoplegia and MV during combined anesthesia prevents MV-induced changes in CI, TPVR, and Qs/Qt. Key words: combined anesthesia, spontaneous respiration, hemodynamics, blood oxygen-transport function.

Objective: to study the hemodynamic effects of sevoflurane during the induction of anesthesia in elderly patients at high risk for cardiac events. Subjects and methods. This study enrolled 32 patients who had a left ventricular ejection fraction of <30% during preoperative examination. According to the presumptive type of anesthesia, the patients were randomized to one of the study groups: In the sevoflurane group receiving infusion of fentanyl (1 ig^kg”‘^hr”‘), anesthesia was induced by sevoflurane at the maximum concentration of 8 vol% at first inspiration, without the respiratory circuit being prefilled. After loss of consciousness, further saturation was carried out using Fianesth, 5 vol%. Combination anesthesia (CA) was that which was induced by successive administration of dormicum, ketamine, propo-fol, and fentanyl. The trachea was intubated during total myoplegia under the control of TOF (TOF-Watch, Organon, the Netherlands). Results. In all the patients under CA, its induction was made during infusion of dopamine (5 lg^kg”‘^min”‘), the dose of which had to be increased up to 10 ig • kg-1 • min-1 in 6 (75%) patients. Nevertheless, there were decreases in mean blood pressure (BPmean) to 46±6 mm Hg and in cardiac index (CI) to 1.5±0.3 fig • kg-1 • min-1 (by 32% of the outcome value). In the sevoflurane inhalation induction group, only 3 (12.5%) patients needed dopamine. Its dose producing a cardiotonic effect was near-minimal; its average maintenance infusion rate was 5.3±0.3 ig^kg”‘^min”‘. The reduction in CI was statistically insignificant; despite a 9% decrease in BPmean, this indicator in the sevoflurane group remained within acceptable ranges. Conclusion. The use of a sevoflurane-based inhalation induction technique permits higher hemodynamic stability in patients at high risk for cardiac events. Key words: inhalation induction, sevoflurane, ketamine, elderly patients.

Objective: to evaluate the blood-saving activity, efficacy, and safety of tranexamic acid. Subjects and methods. Thirty-seven patients allocated into two groups were enrolled in the study of the efficacy of tranexamic acid as an agent in reducing blood loss during hip joint replacement. Group 2 patients were injected tranexamic acid, 10 mg/kg body weight, 20—30 minutes before and 3 hours after surgery in the same dosage. This resulted in a significant (48.5%) reduction in total blood loss (from 1089.6 to 560.8 ml) (p<0.05). No tranexamic acid-induced complications were found. The administration of tranexamic acid during total endoprosthetic replacement of the hip joint could reduce blood loss by 35 and 59.4% in the intraoperative and postoperative periods, respectively, and total blood loss by 48.4%. The use of tranexamic acid allows one to refuse transfusion of blood components during total endoprosthetic replacement of the hip joint. Key words: hip joint replacement, blood loss, tranexamic acid.