We tested the hypothesis that BIS values are altered in pediatric patients with hydrocephaly. We also tested the hypothesis that BIS values are altered in adult post cerebral hemorrhage patients with hydrocephaly undergoing ventricular-peritoneal shunt placement

Context: Enlarged skull circumference in patients with hydrocephalus might alter bispectral index (BIS) values; as distorted skull contour distances sensors from a shifted cerebral mass as well as mental dysfunction as a result of disrupted Cerebrospinal fluid circulation.

Objectives: Investigators tested the hypothesis that BIS values are altered in pediatric patients with hydrocephaly. Investigators also tested the hypothesis that BIS values are altered in adult post cerebral hemorrhage patients with hydrocephaly undergoing ventricular-peritoneal shunt placement.

Methods: After ethics committee approval participants, or their next of kin, who gave written informed consent were recruited in the study. Investigators excluded potential participants suffering from hepatic disease. In the first study 15 pediatric patients with hydrocephaly and 15 pediatric control patients at approximately the same age group were included in the study.

In the second study 15 post cerebral hemorrhage adult patients undergoing ventricular-peritoneal shunt placements and 15 adult control patients were included in the study.

2 BIS sensors were placed on patients' forehead and connected to BIS-Vista monitors. In a quiet anesthesia induction room investigators recorded BIS-Vista for 10 min before induction.

Remifentanil 4 ng ml-1 was started and propofol TCI was kept constant at 4 microg ml-1 with no adjustments for a 1 h anesthesia maintenance study-recording period when time of surgery allowed. Investigators also noted BIS values immediately before and after a patent ventricular-peritoneal shunt was successfully installed. After conclusion of surgical procedures, remifentanil and propofol infusions were terminated and this marked the beginning of the recovery phase of the study where we recorded BIS values for another 20 min emergence from anesthesia.

Inclusion Criteria: . In the first study 15 pediatric patients with hydrocephaly and 15 pediatric control patients at approximately the same age group will be included in the study.

In the second study 15 post cerebral hemorrhage adult patients undergoing ventriculo-peritoneal shunt placements and 15 adult control patients will be included in the study.

Exclusion Criteria: Patients with Liver disease

. In the first study 15 pediatric patients with hydrocephaly and 15 pediatric control patients at approximately the same age group will be included in the study.

In the second study 15 post cerebral hemorrhage adult patients undergoing ventriculo-peritoneal shunt placements and 15 adult control patients will be included in the study.