Background: The concept of CPPopt, a variable cerebral perfusion pressure (CPP) target based on cerebrovascular autoregulatory capacity in severe traumatic brain injury (TBI), is promising. CPPopt calculation is based on the continuous plotting of the pressure reactivity Index (PRx) against CPP and requires processing of waveform quality data. The aim of this study is to investigate whether CPPopt can also be calculated based on minute-by-minute data.
Methods: A low-resolution autoregulation index (LAx) was defined as the minute-by-minute intracranial pressure-mean arterial pressure correlation over varying time intervals. A matrix of LAx-CPP plots was built using different LAx values and varying time windows. CPPopt was calculated as the weighted average of the CPPopt values resulting from each plot. The method was assessed in a database of 21 patients with TBI with 60-Hz data.
Results: No significant difference was observed between PRx-based and LAx-based CPPopt values. The new method was able to issue a CPPopt recommendation throughout almost the entire monitoring time. The absolute difference between CPP and CPPopt was inversely associated with survival.
Conclusion: CPPopt calculation based on standard resolution data compared well with PRx-based CPPopt and may represent a promising alternative method, avoiding the need for waveform quality data capture. Further validation of this new method is required.
Keywords: Cerebral perfusion pressure; Pressure autoregulation; Traumatic brain injury.