[Effects of ibuprofen and OKY-046 on ventilation perfusion distribution in acute respiratory failure]

Hydrochloric acid was injected into the trachea to produce acute respiratory failure in 18 anesthetized dogs. Six dogs were pretreated with ibuprofen (12.5 mg/kg), six dogs were given OKY-046 (0.5 mg/kg), and the remaining six were taken as controls. Distribution of ventilation-perfusion was evaluated by inert gas elimination technique. Acid aspiration caused a prompt decline in PaO2 with an increased perfusion to shunt and low VA/Q lung regions. Pretreatment with ibuprofen reduced pulmonary blood flow to shunt and low VA/Q regions for the first 2 hours after acid aspiration and attenuated hypoxemia, causing an increase in PVR. However, OKY-046, a thromboxane synthetase inhibitor, did not ameliorate acid-induced VA/Q mismatching and hypoxemia.