[CLINICAL ASPECTS OF THE BLOOD LACTATE DYNAMICS DURING OPERATIONS ON THE HEART AND THE AORTA IN CONDITIONS OF CARDIOPULMONARY BYPASS.]

BACKGROUND: The frequency and the causes for the development of hyperlactatemia during operations on the heart and aorta in conditions of cardiopulmonary bypass (CB) is not adequately described in the literature. THE AIM: To study the clinical significance of the lactate dynamics in arterial blood depending on the source ofpathology, stages of operation, basic parameters of cardiopulmonary bypass, the characteristics of the post-perfusion period, and to identify ways to prevent the development of intraoperative hyperlactatemia in surgical interventions on the heart and aorta. MATERIALS AND METHODS: 420 adult cardiac surgery patients operated on the heart and ascending aorta were examined. All patients were operated on under balanced General anesthesia, CB in hypothermic or normothermic mode. Lactate level in arterial blood and the frequency of hyperlactatemia were analyzed at the following stages of operation: after induction of anesthesia, prebypass period, during CB, in the postbypass period and at the time of admission of the patient in the ICU. During CB we analyzed the duration of the CB, the degree of hemodilution, calculated value of oxygen delivery. Oxygen consumption was recorded in the current mode, the monitor CDI-500. Hyperlactatemia was considered the concentration of lactate above 3 mmol/L. RESULTS: Preperfusion period in all groups of cardiac surgery patients was characterized by a normal level of blood lactate in the absolute majority ofpatients, the frequency of hyperlactatemia did not exceed 1%. Hemodynamic stability was achieved without the use of catecholamines by optimizing volemia and heart rate. While CB showed a trend of increasing lactate on average in comparison with the previous period in patients operated on the heart. Duration CB less than 3 hours was not a factor in the development of hyperlactatemia, provided that oxygen delivery in all patients during perfusion exceeded 300 ml/min/m2, hematocrit ofperfusate at the end of CB was at 25-27% in most patients. To maintain it at a large hemodilution the ultrafiltration hemoconcentration was used. The frequency of hyperlactatemia was 3%. A significant increase in lactate concentration at the end of the CB to 3.39k1,3 mmol/l (range of 2.1-7.2 mmol/l) on the background of metabolic acidosis found only in patients with circulatory arrest due to receipt of blood products of anaerobic glycolysis after the resumption of the CB. They have frequency of hyperlactatemia risen to 29%. The lac- tate average value at admission ofpatients in the ICU with application of 50-60% ofpatients in dopamine/dobutrex at a dose of 5 mcg/kg/min and reaching the targets of transfusion therapy was slightly higher in the baseline period and corresponded to the upper level of normal values. Only during operations on the aortic arch under conditions of circulatory arrest, the concentration of lactate at the end of the operation was 3,4+1,1 mmol/l with a tendency to decrease in comparison with the period of the CB. From 88 to 93% patients during operations on the heart and ascending aorta without circulatory arrest and 64% ofpatients after operations on the aortic arch with circulatory arrest were admitted to the ICU with a normal lactate level in arterial blood Conclusion. The duration ofperfusion less than 3 hours in the conditions of these indicators preservation is not a risk factor for the development of hyperlactatemia. In postbypass period during operations on the heart and aorta without circulatory arrest about 90% ofpatients transferred to the intensive care unit (ICU) with normal values of lactate. During operations on the aortic arch with circulatory arrest about 60% ofpatients have normal levels of lactate at admission from the operating room to the ICU.

[Strategy of transfusion in cardiac and aortic surgery].

Current trend in transfusion is a decreasing of the donor's blood use due to possible complications. The article deals with analysis of intraoperative blood loss in different surgeries on the heart and aorta and of a role of blood-saving factors in decreasing of the donor's blood transfusion. We found a correlation between the blood components need and type of surgery and assessed a preoperative provision of autoplasma and intraoperative autohemotransfusion with a blood sampling from the right atrium before the beginning of artificial circulation (Complex use of the blood-saving methods with a prophylactics and treatment of hemostasis disturbances allowed the significantly decreasing of the donor's blood use. 50-70% of patients did not receive components of the donor's blood during cardiac surgery.

[Tissue oxygenation monitoring during cardiac surgery].

UNLABELLED: The aim of this study was to evaluate tissue oxymetry dynamics in patients with different initial tissue oxygenation levels and to analyze the relation of these data with the perioperative period flow peculiarities. PATIENTS AND METHODS: 92 patients undergoing on-pump myocardium revascularization or valve replacement were included in the study. Regional oxygenation in all patients was monitored with FORE-SIGHT Laser Tissue Oximeter. Sensors were located in the right hemisphere projection and on right forearm. Tissue (StO2) and cerebral (SctO2) oxygenation data were analyzed before anaesthesia start, before CBP on 45th -minute of CPB and in the end of the operation. At these stages also was performed standardized time (3 minutes) vessel occlusion test (VOT). RESULTS: None patients had episodes of StO2, decrease below the critical level during the operation, that allows to talk about central haemodynamics stability during the study. 1st group - patients with initial StO2, below 70% (n=19). In this group StO2, remain low throughout the operation. 2nd group- patients with initial StO2, over 70%, but before CPB decreased below 70% (n=49). 3rd group - patients with high StO2, throughout anaesthesia. VOT data confirmed tissue oxygenation disturbances in Ist and 2nd groups. In st group oxygen reserve (OR) was lower than in other groups and at the end of the surgery - lower than initial one. In 2nd group OR decreased significantly before CPB and during CPB didn't differ from 1st group. In 3rd group OR during anaesthesia was higher, than in 1st and 2nd group, but decreased by the end of the surgery. Lactate level after CPB doesn't exceed the upper limit, however, it's level was higher in the 1st and 2nd group than in the 3rd group. Central vein saturation in 3rd group was higher than in the Ist and 2nd group at all stages, except for operation start. Lower StO2, levels in 1st and 2nd group were accompanied with extension of ALV ICU length-of-stay and hospitalization. RESUME: Tissue oxymetry may be useful for regional oxygenation assessment during anesthesia. There is a decrease in tissue oxygenation and oxygen reserve of peripheral tissues during on-pump cardiosurgery The low tissue oxygenation level during preperfusion period may be a predictor for early postoperative complications.

[Efficiency and controllability of esmolol (breviblock)-induced adrenergic blockade during the heart and aorta surgery].

This article contains analysis of retrospective and prospective studies of use of selective ultrashort Beta-blocker esmolol during intraoperative period in cardiac surgery patients in recent years. The drug is highly effective and controlled the means for prevention and treatment of tachycardia, arising as a result of the sympathoadrenal system activation during anaesthesia induction (laryngoscopy, trachea intubation) and intraoperative period (during heart and aorta manipulations). It should be considered that the use of esmolol has dose-dependent effect. For the treatment of tachycardia against the background of hypertension is recommended dose of 0.6-1.0 mg/kg, with normal blood pressure it is recommended to decrease the esmolol dose up to 0.3-0.6 mg/kg. It is possible to use esmolol-infusion in the dose of 50-200 g/kg/min prolonging adrenergic blockade during heart and aorta surgery.

[Unintended cooling, active warming, and microcirculation in cardiosurgical patients].

The study was undertaken to compare various methods to maintain a patient's body temperature and to evaluate their impact on microcirculation during myocardial revascularization under normothermal extracorporeal circulation (NTEC). The study enrolled 50 patients with NYHA Functional Classes III-IV coronary heart disease, who underwent aortocoronary bypass surgery under NTEC. A HICO-AQUATHERM 660 water-warming unit (Hirtz, Germany) was used in Group 1 patients (n=30). A Bair Hugger air-warming unit (Arizant, U.S.A.) with a mattress located under a patient was employed in Group 2 (n=20). Intraoperative microcirculation monitoring was carried out by a laser analyzer (Lazma, Moscow).