ABSTRACT
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 intracranial hypertension may have a direct effect on sCA.
Subject(s)
Intracranial Hypertension , Intracranial Pressure , Animals , Blood Pressure , Cerebrovascular Circulation , Homeostasis , Intracranial Hypertension/etiology , SwineABSTRACT
BACKGROUND: This study aimed to analyse cerebral autoregulation (CA) during induction and treatment of intracranial hypertension (ICH) in an experimental model. MATERIALS AND METHODS: Landrace and Duroc piglets were divided into mild and severe ICH groups. Four or seven millilitres of saline solution was infused into paediatric bladder catheter inserted in the parietal lobe (balloon inflation). After 1.5 h, a 3% saline solution was infused via venous catheter, and 30 min later, the bladder catheter balloon was deflated (surgery). The cerebral static autoregulation (sCA) index was evaluated using cerebral blood flow velocities (CBFV) obtained with Doppler ultrasound. RESULTS: Balloon inflation increased ICP in both groups. The severe ICH group showed significantly lower sCA index values (p=0.001, ANOVA) after balloon inflation (ICH induction) and a higher sCA index after saline injection (p=0.02) and after surgery (p=0.04). ICP and the sCA index were inversely correlated (r=-0.68 and p<0.05). CPP and the sCA index were directly correlated (r=0.74 and p<0.05). CONCLUSION: ICH was associated with local balloon expansion, which triggered CA impairment, particularly in the severe ICH group. Moreover, ICP-reducing treatments were associated with improved CA in subjects with severe ICH.
