Continuous determination of optimal cerebral perfusion pressure in traumatic brain injury

Critical Care Medicine, 08/03/2012

Aries MJH et al. – Real–time optimal cerebral perfusion pressure (CPPopt) could be identified during the recording time of majority of the patients. Patients with a median CPP close to CPPopt were more likely to have a favorable outcome than those in whom median CPP was widely different from CPPopt. Deviations from individualized CPPopt were more predictive of outcome than deviations from a common target CPP. CPP management to optimize cerebrovascular pressure reactivity should be the subject of future clinical trial in severe traumatic head–injury patients.

Methods

  • A total of 327 traumatic head-injury patients admitted between 2003 and 2009 with continuous monitoring of arterial blood pressure and intracranial pressure.
  • Arterial blood pressure, intracranial pressure, and CPP were continuously recorded, and pressure reactivity index was calculated online.
  • Outcome was assessed at 6 months.
  • An automated curve fitting method was applied to determine CPP at the minimum value for pressure reactivity index (CPPopt).
  • A time trend of CPPopt was created using a moving 4-hr window, updated every minute.

Results

  • Identification of CPPopt was, on average, feasible during 55% of the whole recording period.
  • Patient outcome correlated with the continuously updated difference between median CPP and CPPopt (chi-square=45, p<.001; outcome dichotomized into fatal and nonfatal).
  • Mortality was associated with relative “hypoperfusion” (CPP<CPPopt), severe disability with “hyperperfusion” (CPP>CPPopt), and favorable outcome was associated with smaller deviations of CPP from the individualized CPPopt.
  • While deviations from global target CPP values of 60mmHg and 70mmHg were also related to outcome, these relationships were less robust.

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