Background and Aims Intracranial hypertension is a serious complication of traumatic brain injury (TBI) in children and adversely affects outcome. Monitoring intracranial pressure (ICP) requires an invasive procedure. The aim of this study was to evaluate the accuracy of a noninvasive method of estimating ICP - transcranial Doppler (TCD) derived Pulsatility Index (PI) - when compared to invasive ICP measurements.
Methods Children admitted to our pediatric intensive care unit with severe TBI and ICP invasive monitoring during the study period (Aug 2008 to Mar 2012) were included in the study. TCD was done in all children and PI calculated.
Results Eighteen children met the inclusion criteria. Male:female ratio was 2.6:1. Mean age at admission was 8.7 years (14 months-17 years). Mortality rate was 11% (2/18). Mean PRISM score was 19 with a predicted mortality rate of 28%. All patients except one had ICP>20 mmHg, with a mean highest ICP of 37 mmHg (16–50). The first measurement of PI had a mean of 1.23 (0.55–2.95). There was a significant correlation between the first PI and corresponding ICP (Pearson correlation coefficient of 0.78; p<0.0001). When all PI were considered (41 measurements) the correlation was not significant. After excluding TCD with signs of vasospasm the correlation was again significant (r=0.67, p<0.001).
Conclusions PI is a non invasive method of evaluating ICP with a strong correlation with invasive ICP measurements at admission. After a few days other factors like vasospasm must be taken into consideration when interpreting PI values.