PEEP is the most important therapeutic intervention in the management of acute respiratory failure. Transitory PEEP disconnection to perform clinically relevant maneuvers is often necessary, but its effect upon PaO2 and physiological shunt in patients requiring high-level PEEP is not clear from the literature.
Nine adult patients in severe respiratory failure requiring high-level PEEP therapy were studied. The elimination of PEEP decreased the PaO2 and increased the physiological shunt. Maximum values were reached in about 4 min. Restoration of PEEP after 7.4 min in zero end-expiratory pressure caused an increase in the PaO2 and decrease in the physiological shunt. Baseline values were restored in about 5 min.
In 4 patients having endotracheal suction under hand ventilation with 100% oxygen, the continuous PaO2 recording showed an increase in PaO2 during the maneuver.
Therefore, necessary manipulations can be accomplished without fear of negating the salutory effects gained by high-level PEEP therapy.