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

CONCLUSION

We conclude that intracranial hypertension may have a direct effect on sCA.