Pulmonary vascular response to high-frequency oscillatory ventilation in dogs: lack of effect of indomethacin

The role of prostaglandins (PG) in the pulmonary hypertension associated with high-frequency oscillatory ventilation (HFOV) was investigated in 7 pentobarbital-anesthetized dogs. The magnitude and time course of the mean pulmonary artery pressure (PAP) changes induced by HFOV (20 Hz) was quantified before and after PG-production blockade with 15 mg/kg indomethacin (INDO) i.v. It was found that HFOV before INDO induced a 27.2 +/- 5.6% increase in PAP above baseline and a 30.0 +/- 7.2% one hour after INDO administration. This difference was not statistically significant. The time course of the PAP changes induced by HFOV before and after blocking PG-production by INDO were also similar. Mean airway pressure, PaO2 and PaCO2 during HFOV, before and after INDO were not statistically different. It is concluded that the acute increase in PAP induced by HFOV is not due to PG release.