Hemodynamic effects of positive end-expiratory pressure. Historical perspective

Mechanical ventilation with positive end-expiratory pressure has been known to increase arterial oxygen content for approximately 40 years. Early experiments demonstrated a diminution of cardiac output with the application of positive end-expiratory pressure, and it was not favored as a therapeutic modality until the 1960s, when it was found to be effective in the treatment of adult respiratory distress syndrome. In recent years, physiologists have methodically scrutinized the effects of positive end-expiratory pressure on each of the major determinants of cardiac output. Review of the progression of thought on this subject reinforces for today's clinician basic principles of cardiac performance and heart-lung interaction.