Asymmetry of pressure autoregulation after traumatic brain injury

Abstract
Object. The aim of this study was to assess the asymmetry of autoregulation between the left and right sides of the brain by using bilateral transcranial Doppler ultrasonography in a cohort of patients with head injuries. Methods. Ninety-six patients with head injuries comprised the study population. All significant intracranial mass lesions were promptly removed. The patients were given medications to induce sedation and paralysis, and artificial ventilation. Arterial blood pressure (ABP) and intracranial pressure (ICP) were monitored in an invasive manner. A strategy based on the patient's cerebral perfusion pressure (CPP = ABP − ICP) was applied: CPP was maintained at a level higher than 70 mm Hg and ICP at a level lower than 25 mm Hg. The left and right middle cerebral arteries were insonated daily, and bilateral flow velocities (FVs) were recorded. The correlation coefficient between the CPP and FV, termed Mx, was calculated and time-averaged over each recording period on both sides. An Mx close to 1...