Impaired vascular reactivity and loss of intracranial compliance will result in ICP changes driven by MAP fluctuations, a concept reflected in the index of pressure reactivity (PRx).
- positive linear correlation between changes in MAP
- reveals an impaired autoregulatory state
- associated with poor outcome following TBI within first 48 h
optimal CPP (CPPopt)
- can be defined using the PRx
- concept: identify a narrow range of CPPs within a patient’s recent real-time data that reflects the state in which there was optimal cerebral vasoreactivity (lowest PRx)
- can be used to spare patients from detriments of passive pressure changes in the autoregulation-impaired brain
- retropective studies showed
- improved outcomes when CPP approximated CPPopt
- higher motality when CPP below CPPopt
- increased survival but worse outcome when CPP elevated above CPPopt
Roh, David and Soojin Park. “Brain Multimodality Monitoring: Updated Perspectives”. Current Neurology and Neuroscience Reports 16.6 (2016): n. pag. Web.