Abstract

The study was undertaken to determine the most adequate tidal volume when used volume preset ventilator during anesthesia. The thirty patients were received controlled mechanical ventilation with constant inspiratory pressure of 10 cmH2O and respiratory frequency of 12/minute. The results were as follows: 1) The PH was 7.39±0.01 and it is within normal limit. 2) The PaCO2 was 34.0±0.6 mmHg and it is a slightly hyperventilatory state. 3) The PaO2 was 228.0±8.2 mmHg. 4) The Buffer base was 20.7±0.3 mEq/L and it is a slightly buffer base deficient state. From the above results. We concluded that if patients were fully relaxed during general anesthesia, it is desirable to maintain the inspiratory pressure of anesthetic mechanical ventilator to 10 cmH2O for adequate alveolar ventilation.