Effect of Pressure Reactivity Index Calculation Settings on the Range of the Optimal Cerebral Perfusion Pressure

The most important task in patients with traumatic brain injury is to prevent the secondary injury. Ensuring an adequate cerebral perfusion has a pivotal role in this concept. One of the approaches in determination of the individual target CPP is computation of the optimal CPP (CPPopt) using the pressure reactivity index (PRx). The PRx index represents the correlation between mean arterial pressure and intracranial pressure. In order to determine the effect of parameters of PRx calculation on the range of CPPopt values, two window lengths (60 s and 300 s) and two critical values of PRx (0.2 and 0.3) were selected. As a result, the choice of the parameters caused differences in the CPPopt range, and the time evaluated as spent in the critical region of cerebral autoregulation. These values could affect the clinician's decision-making in patient treatment if the CPPopt is used at the bedside.