Hypocapnic and normocapnic ventilation in hepatic encephalopathy: a comparision

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Purpose

Encephalopathy with raised intracranial pressure is the major cause of death in hepatic failure [1].We investigated role of arterial hypocapnia, achieved by hyperventilation, in the management of hepatic encephalopathy.

Methods

In a prospective study of twenty-two patients, with fulminant hepatic failure with grade IV encephalopathy receiving mechanical ventilation, two groups of twelve (group I) and ten (group II) patients had PaCO₂ in the range of 25–30 mmHg (group I) and 35–40 mmHg (group II). Tidal volume was kept in the range of 8–10 ml per kg and respiratory rate in the range of 12–20 per min.

Results

The demographic data was comparable in both the groups. The shortest duration of recovery was 8 h in group I and 30 h in group II.. Survival was 20% group I and 41.66% group II. No adverse effects, secondary to hypocapnia, were noticed in group I.

Conclusion

Improved survival in the normocapnic group may indicate that normocapnic ventilation may be preferred over hypocapnic ventilation, particularly if the patients of hepatic encephalopathy are being managed without cerebral perfusion pressure and ICP monitoring.