The global importance of the anesthetic protection in thoracic surgery belongs to the methods of anesthesia and respiratory support, which ensure the optimal level of gas exchange. The paper presents the results of the study of factors and patterns that affect the efficiency of gas exchange in the lungs under anesthesia based on inhaled halogen-containing anesthetics.
The aim of the study is to determine the capabilities of the modern inhaled anesthetics (desflurane, sevoflurane, isoflurane) to affect the effectiveness of gas exchange in the lungs.
Materials and methods: the study included 58 patients of II-IV degree of risk (ASA). Thoracotomy or innovative thoracoscopic access to the surgical field was done. The main anesthetic: desflurane (DF) - 23 patients, sevoflurane (SF) -16 patients, isoflurane (IF) - 19 patients. Were studied the indicators of systemic, pulmonary, intracardiac hemodynamics with the pulmonary thermodilution (PT) method with the analysis of gas exchange and lung metabolism, acid-base balance, gas and electrolytic balance of arterial and mixed venous blood.
Stages of the study: Stage 1 - after induction into anesthesia, under conditions of ventilation of both lungs (ALV-1); Stage 2 in conditions of surgical pneumothorax and artificial one-lung ventilation OLV); 3 and 4 stages the main stage of the operation with OLV 60, 80-120 minutes; Stage 5 the end of the main stage of the operation with both lungs ventilation (ALV-2).
Results: There were identified the influence of DF and SF on gas exchange blood flow in all variants of respiratory regimes (pre- and post-capillary resistance). A significant difference in the total peripheral resistance at stages 1, 3 and 4 with DF was comparable to the IF effect. A higher pump coefficient of the right ventricle was received with DF at all stages of the study, as well as a smaller amount of physiological dead space.
Conclusion: We assume that the systemic vasodilating effect of desflurane extends to the bronchial blood flow, as an integral part of the systemic circulation, as well as to vessels of extracapillary perfusion. Simultaneously, in comparison with SF, a smaller amount of physiological dead space with DF indicates a larger area of the perfused gas exchange surface under conditions of OLV. A higher pump coefficient of the right ventricle with DF at all stages of the study is a sign of its cardioprotective effect.
Key words: Desflurane, one-lung ventilation; thoracic anesthesia; extracapillary perfusion; pulmonary thermodilution; thoracoscpic surgical technologies