Immediate and middle-term cardiorespiratory effects of positive end-expiratory pressure in thirteen cases of non-haemodynamic pulmonary oedema.

Thirteen patients with severe acute respiratory failure were ventilated with positive end-expiratory pressure (PEEP) for 9 days. Haemodynamic measurements were performed after 15 min during 100% oxygen breathing, first with intermittent-positive pressure ventilation, secondly with positive end-expiratory pressure. The latter improved the Pa, O2 from 89 to 150 torr, decreased the QS/QT from 43% to 32% and decreased the Pa, CO2 from 37 to 34 torr; this improvement in gas exchange was accompanied by a decrease in cardiac index from 4.4 to 3.7 1 min-1m-2 without changing the systemic arterial pressure. Despite this beneficial effect on arterial blood oxygenation, it did not improve the survival rate of patients with severe acute respiratory failure.