Masui. The Japanese journal of anesthesiology
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Eight patients, of ASA physical status I or II soon after total knee replacement under general anesthesia, were studied to compare negative extra-thoracic pressure ventilation (NETPV) with positive airway pressure ventilation (PAPV). The measured parameters during the two ventilatory modes were tidal volume, arterial blood gas and functional residual capacity change (delta FRC). ⋯ When the patients were ventilated with the same values of minute ventilation on NETPV and PAPV, there was no significant difference in blood gas values. These findings suggest that efficiency of NETPV is less than that of PAPV at the same absolute working pressure but pulmonary gas exchange of NETPV is almost equal to that of PAPV at the same minute ventilation in the normal lung.