The effect of variations in positive end expiratory pressure on gas exchange in ventilated children with liver disease.

The effect of varying the positive and expiratory pressure (PEEP) level during mechanical ventilation has been assessed in ten children with liver disease, mean age 3.8 years. PEEP was increased 3 cmH2O above the child's original (baseline) PEEP level and then decreased either by 3 cmH2O below the baseline or to 0 cmH2O. In all ten children increasing the PEEP above the baseline improved oxygenation; in the group overall the median PaO2 increased from 90 mmHg to 97 mmHg (P < 0.01). In eight of ten children decreasing the PEEP level below the baseline resulted in a deterioration in oxygenation; in the group overall the median PaO2 decreased from 91 mmHg to 82 mmHg (P < 0.05). Changes in PEEP levels, however, did not result in clinically significant alterations in PaCO2, heart rate or blood pressure. We conclude that modest increases in PEEP are well tolerated in children with liver disease and result in an improvement in oxygenation.