Abstract
Title Utility of transcranial Doppler (TCD) in estimating cerebral perfusion pressure (eCPP)
in traumatic brain injury—a prospective observational trial.
Aim To validate the utility of a noninvasive technique of eCPP estimation using transcranial
Doppler (TCD).
Materials and Methods Eighteen patients with severe traumatic brain injury (TBI) requiring intracranial
pressure (ICP) monitoring as per the Brain Trauma Foundation guidelines were prospectively
recruited for the study. ICP was measured in all patients using an intraventricular
catheter. Mean arterial pressure (MAP) was recorded from an intra-arterial catheter.
Cerebral perfusion pressure (CPP) was calculated as the difference between MAP and
ICP. Middle cerebral blood flow velocities were recorded using TCD, and CPP was estimated
from the middle cerebral artery (MCA) flow velocities (eCPP) using the formula eCPP
= (MAP × end diastolic velocity [EDV]/mean velocity [MV]) + 14. Total 185 simultaneous
readings of CPP and eCPP were available for analysis. Reliability statistics between
CPP and eCPP were computed to calculate the intraclass correlation (ICC).
Results The average CPP measured using intraventricular catheter was 73.2 (+/−12.4), and
the mean estimated eCPP was 76.7 (+/−10.9). We found a very good Pearson's correlation
between CPP and eCPP (r = 0.743) with a Cronbach's α of 0.843. In 86.2% of examinations, the estimation error
of measuring CPP was within 10 mm Hg, and in 93.1% examinations, it was within 15
mm Hg.
Conclusion eCPP estimated using TCD can serve as reliable noninvasive alternative in situations
in which ICP monitoring is not available, even in moderate or mild head injury.
Keywords
cerebral perfusion pressure - intracranial pressure - transcranial Doppler
