Positive-pressure ventilation with positive end-expiratory pressure and atrial natriuretic peptide release

The effect of positive-pressure ventilation (PPV) with PEEP on the release of alpha-atrial natriuretic peptide (ANP) was investigated in both humans and an experimental model. In the human study, systemic artery blood samples from 22 critically ill patients were analyzed for ANP. Seventeen of these patients received PPV with different levels of PEEP (5 to 15 cm H2O). The remaining five patients were breathing spontaneously (0 PEEP). There was no significant difference in plasma levels of ANP obtained at different levels of PEEP, and no correlation between ANP vs. wedge pressure or CVP was found. For the experimental group, in six dogs a PEEP dose-response curve was established (PEEP 0, 5, 10, 15, 0 cm H2O every 45 min). Blood samples from pulmonary and systemic arteries were obtained for ANP determination, and urine and Na excretion were measured at the end of each period. Neither significant interaction between PEEP and ANP was observed, nor did levels of this peptide correlate with the decrease in cardiac output (p less than .05) and urine output (p less than .05), or with the increase in CVP (p less than .05) observed during PEEP. ANP concentrations in the pulmonary and systemic arteries were similar. In 14 human samples, ANP was determined by radioimmunoassay and radioreceptor assay systems, but the level obtained by both methods did not significantly correlate.(ABSTRACT TRUNCATED AT 250 WORDS)