[Sevoflurane and isoflurane during thoracic operations under artificial one-lung ventilation in patients at a high surgical and anesthesiological risk].

The specific features of balanced anesthesia utilizing sevoflurane (versus isoflurane) during thoracic operations under artificial one-lung ventilation (AOL ) have been studied in patients at high operative and anesthetic risks. Unlike isoflurane, sevflurane fails to cause vasodilatation in both the greater and lesser circulation (including in the gas-exchange part ofpulmonary circulation). The difference of the anesthetics in their vasodilating capacity in the vessels of pulmonary and systemic circulation determines various mechanisms of pathophysiological and adaptive circulatory changes in pulmonary collapse and under AOL V Under sevoflurane anesthesia, compensatory blood flow limitation along the collaborated lung due to permanently vasohypertension in gas-exchange microcirculation is accompanied by a systemic circulatory response that is aimed at reducing right ventricular load. Termination of hypoxic pulmonary vasoconstriction in the collaborated lung occurs not early than 80-125 min of AOLV, fails to lead to recovery of impaired gas exchange due to vasohypertension and high shunt in the ventilated lung, and is attended by right ventricular overload. The latter differentiates sevoflurane anesthesia from isoflurane one wherein completion of pulmonary hypoxic vasoconstriction upon 80-125-min exposure to AOL V results in the recovery of gas exchange to the baseline levels. The pattern of reperfusion changes in ventilation emergence in the operated lung under anesthesia using both sevoflurane and isoflurane is of no significant pathological tinge and it is followed by no pulmonary and systemic metabolic disturbances. Isoflurane should be recognized to be preferable component at the stage of anesthesia maintenance in patients with cardiopulmonary diseases during thoracic operations under prolonged AOL V (more than 2 hours).