[The effect of cyclooxygenase and thromboxane synthetase inhibition on oxygen metabolism in canine acute respiratory failure].

The purpose of this study is to evaluate the effect of cyclooxygenase inhibitor and thromboxane synthetase inhibitor on oxygen metabolism in acute respiratory failure. Acid aspiration was induced in 18 dogs. Six dogs were pretreated with ibuprofen (IBU), six with OKY-046 (OKY), and the remaining six used as control. After acid aspiration oxygen delivery (DO2) fell in all groups as a result of decreased PaO2 and cardiac output. However, oxygen consumption (VO2) was maintained in all animals by the end of the experiment except in the control group. Arterial oxygen content was maintained at baseline level throughout the experiment in IBU group. Meanwhile a significantly decreased mixed venous oxygen tension was found in OKY group after acid challenge. Linear regression of VO2 and DO2 was confirmed in both the control and OKY groups. However, the dependent relationship between VO2 and DO2 was not identified in IBU group; this may indicate that the body oxygen metabolism was maintained rather well in acute respiratory failure dogs treated with ibuprofen.