Effects of alfentanil on intracranial pressure in children undergoing ventriculoperitoneal shunt revision

Abstract

The effects of alfentanil on intracranial pressure in patients with diminished intracranial compliance has not been established. Ten patients with hydrocephalus of varying etiologies, ages 16 months to 20 yr, presenting for ventriculoperitoneal shunt revision were studied. Following induction of anesthesia with thiopental, nitrous oxide/oxygen, and isoflurane, the trachea was intubated and anesthesia was maintained with isoflurane (0.5%), nitrous oxide (70%), and oxygen. After a minimum of 30 min and after the new shunt was placed, alfentanil was administered in increments of 10, 20, and 40 μg/kg at 3-min intervals, and intracranial pressure was measured over 12 min via the new shunt. In these unstimulated, normocapnic (PET(CO2) 32-38 mmHg) patients, heart rate, mean arterial pressure, and cerebral perfusion pressure declined from 110 ± 26 beats/min, 90 ± 11 mmHg, and 71 ± 14 mmHg, to 84 ± 25 beats/min, 66 ± 11 mmHg, and 45 ± 16 mmHg (mean ± SD), respectively, by 3 min after the third dose (P < 0.001). Intracranial pressure did not change from baseline (19 ± 14 mmHg vs. 21 ± 11) after any dose of alfentanil. Contrary to earlier studies in adult patients with brain tumors, the authors found that alfentanil, in pediatric patients with hydrocephalus anesthetized with oxygen, nitrous oxide, and isoflurane, did not increase intracranial pressure within a 9-min study period. The significant decreases in cerebral perfusion pressure observed merit concern and further study.