Confusion with cerebral perfusion pressure in a literature review of current guidelines and
survey of clinical practice
Sammanfattning
BACKGROUND:
Cerebral perfusion pressure (CPP) is defined as the difference between the mean arterial pressure
(MAP) and the intracranial pressure (ICP). However, since patients with traumatic brain injury (TBI) are
usually treated with head elevation, the recorded CPP values depends on the zero level used for
calibration of the arterial blood pressure. Although international guidelines suggest that target values
of optimal CPP are within the range of 50 - 70 mmHg in patients with TBI, the calibration of blood
pressure, which directly influences CPP, is not described in the guidelines.The aim of this study was
to review the literature used to support the CPP recommendations from the Brain Trauma Foundation,
and to survey common clinical practice with respect to MAP, CPP targets and head elevation in
European centres treating TBI patients.
METHODS:
A review of the literature behind CPP threshold recommendations was performed. Authors were
contacted if the publications did not report how MAP or CPP was measured. A short questionnaire
related to measurement and treatment targets of MAP and CPP was sent to European neurosurgical
centres treating patients with TBI.
RESULTS:
Assessment methods for CPP measurement were only retrieved from 6 of the 11 studies cited in the
TBI guidelines. Routines for assessment of CPP varied between these 6 publications. The 58
neurosurgical centres that answered our survey reported diverging routines on how to measure MAP
and target CPP values. Higher CPP threshold were not observed if blood pressure was calibrated at
the heart level (p = 0.51).
CONCLUSIONS:
The evidence behind the recommended CPP thresholds shows no consistency on how blood
pressure is calibrated and clinical practice for MAP measurements and CPP target values seems to
be highly variable. Until a consensus is reached on how to measure CPP, confusion will prevail.