Non-invasive estimation of cerebral perfusion pressure using transcranial Doppler ultrasonography in children with severe traumatic brain injury

Objective To identify if cerebral perfusion pressure (CPP) can be non-invasively estimated by either of two methods calculated using transcranial Doppler ultrasound (TCD) parameters. Design Retrospective review of previously prospectively gathered data. Setting Pediatric intensive care unit in a tertiary care referral hospital. Patients Twenty-three children with severe traumatic brain injury (TBI) and invasive intracranial pressure (ICP) monitoring in place. Interventions TCD evaluation of the middle cerebral arteries was performed daily. CPP at the time of the TCD examination was recorded. For method 1, estimated cerebral perfusion pressure (CPPe) was calculated as: CPPe = MAP × (diastolic flow (Vd)/mean flow (Vm)) + 14. For method 2, critical closing pressure (CrCP) was identified as the intercept point on the x -axis of the linear regression line of blood pressure and flow velocity parameters. CrCP/CPPe was then calculated as MAP-CrCP. Measurements and main results One hundred eight paired measurements were available. Using patient averaged data, correlation between CPP and CPPe was significant ( r = 0.78, p =