Impact of combined anesthesia using isoflurane on the development of adaptation mechanisms on changing ventilation conditions in thoracic surgery

: The paper deals with the effect of isoflurane (IF) as a component of combined anesthesia during thoracic interventions in the lateral position on the development of adaptation mechanisms to a change in artificial ventilation (AV) modes--from ventilation of both lungs to that of one lung (unilateral ventilation, ULV), long exposure to ULV and to a change from ULV to ventilation of both lungs. Eighteen patients at a high operation-anesthetic risk were examined. Measurements were made in 6 steps, including conditions in AV, exposure to ULV for 15-30, 55-60, and 80-120 minutes, AV after 20-min exposure to ULV, and at the end of surgery in the supine position. While analyzing the results, the authors made an important observation that IF has a property of preventing capillary formation in the ventilated portions, without impairing the mechanism of pulmonary hypoxic vasoconstriction in the area of atelectized alveoles. This contributed to the optimization of a ventilation-perfusion relationship and creates conditions for adequate oxygenation. The use of IF as a component of combined anesthesia during thoracic operations associated with a need for artificial unilateral ventilation in patients at a high operation-anesthetic risk created conditions for optimizing gas exchange and blood circulation at all stages of an operation and anesthesia.