The influence of intracranial hypertension on static cerebral autoregulation.

OBJECTIVES: To analyze the influences of mild and severe intracranial hypertension on cerebral autoregulation (CA).

PATIENTS AND METHODS: Duroc piglets were monitored with an intracranial pressure (ICP) catheter. Intracranial hypertension was induced via infusion of 4 or 7 ml of saline solution by a bladder catheter that was inserted into the parietal lobe. The static cerebral autoregulation (sCA) index was evaluated via cerebral blood flow velocities (CBFv). Piglets with ICPs ≤ 25 and > 25 mmHg were considered as group 1 and 2, respectively. Continuous variables were evaluated using the Kolmogorov-Smirnov goodness-of-fit test. The main parameters were collected before and after ICH induction and compared using two-factor mixed-design ANOVAs with the factor of experimental group (mild and severe ICH).

RESULTS: In group 1 (ICP ≤ 25 mmHg), there were significant differences in sCA ( p = .01) and ICP ( p = .0002) between the basal and balloon inflation conditions. In group 2 (ICP > 25 mmHg), there were significant differences in CBFv ( p = .0072), the sCA index ( p = .0001) and ICP ( p = .00001) between the basal and balloon inflation conditions.

CONCLUSION: We conclude that ICH may have a direct effect on mild and severe sCA.