The effect of atrial natriuretic peptide on pulmonary acid injury in a pig model.

The effect of exogenous atrial natriuretic peptide (ANP) on pulmonary injury induced by aspiration of hydrochloric acid (0.1 N HCl, 2.0 ml/kg) was examined in anesthetized pigs ventilated with 100% oxygen. Group-specific diuretic treatment was used 60 min after aspiration and followed for a further 120 min. No diuretics were used for Group 1, 0.1 microg/kg/min of ANP was infused intravenously for 60 min in Group 2, and 0.05 mg/kg of furosemide was injected (intravenous bolus) in Group 3. Total urine volume after diuretic treatment did not differ significantly between Groups 2 and 3. However, the increase in PaO2 (to 386.3 +/- 67.5 mm Hg) after infusion of ANP was significantly higher than the increase in PaO2 (to 275.9 +/- 63.3 mm Hg) after furosemide treatment, and in the no treatment control (to 171.1 +/- 31.5 mm Hg). Pulmonary hypertension induced by acid aspiration was significantly reduced (p < 0.01 versus Groups 1 and 3) during ANP infusion. ANP has a beneficial effect on acute lung injury, possibly through its diuretic and/or pulmonary vasodilating action.