Arterial Oxygenation During Hypothermia

The aims of this stady were: to investigate a possible significant relation between the size of the tidal volume during constant volume ventilation and the rate of change of the alveolar-arterial oxygen tension gradient (AaDO2): to determine whether hypothermia significantly affects this relationship; and to test the accuracy of correction factors previously proposed for the effect of temperature on the oxygen tension of fully saturated blood. Ten patients were surface cooled to 30° C. for over 24 hours. Anesthesia consisted of pentobarbital sodium and d-tubocurarine. Constant volume pulmonary ventilation with 100 per cent oxygen was provided by a piston pump. A significant relationship (P < 0.01) was found between the size of the constant tidal volume and the rate of increase or decrease of the AaDO2. This relation showed little evidence of being affected by hypothermia per se. The accuracy of previously determined temperature correction factors for oxygen tension was confirmed.