Intracranial pressure during wakefulness and sleep in 55 adult patients with chronic hydrocephalus.

OBJECTIVE

To record the levels of intracranial pressure (ICP) during wakefulness and sleep in hydrocephalic adults and to correlate the ICP levels with symptoms and degree of improvement after surgical treatment.

METHODS

ICP and patient behavior were registered overnight (17-26 h) in 29 patients with noncommunicating and 26 with communicating hydrocephalus. Mean ICP was calculated during wakefulness (sitting or lying supine) and during sleep. Clinical symptoms and changes after surgery were scored on a continuous scale.

RESULTS

Mean ICP during sleep was 13.4 mmHg (11.1-15.7 mmHg) in noncommunicating hydrocephalus versus 10.1 mmHg (8.8-11.4 mmHg) in communicating hydrocephalus (P < 0.001). Patients with idiopathic communicating hydrocephalus had higher ICP, 11.4 mmHg (9.9-12.9 mmHg), than patients with secondary communicating hydrocephalus, 8.6 mmHg (6.5-10.6 mmHg). ICP was higher during sleep than when the patients were awake lying supine, 10.9 mmHg (8.7-13.1 mmHg) in noncommunicating versus 6.8 mmHg (5.3-8.3 mmHg) in communicating hydrocephalus (P < 0.0001). The mean ICP in the sitting position was 2.4 mmHg (0.5-4.3 mmHg) in noncommunicating versus 0.5 mmHg (-0.7-1.8 mmHg) in communicating hydrocephalus. All but one patient with communicating hydrocephalus had a normal ICP (< or = 15 mmHg) versus 20 of the 29 patients with noncommunicating hydrocephalus. ICP levels showed no correlation with either symptoms or improvement after surgery.

CONCLUSION

ICP is higher during sleep than during periods of awake lying supine (P < 0.001) and is not correlated with either symptoms or the rate of improvement after surgery. ICP is normal in most adults with hydrocephalus.