Reduced complexity assessed by entropy and fractal analysis during intracranial hypertension has been reported.1,2 The present study applied a more sophisticated method, Multiscale Entropy (MSE), to investigate the complexity of slow fluctuations in intracranial pressure (ICP) and its relationship with the outcome after traumatic brain injury (TBI).
290 TBI patients were enrolled retrospectively. ICP and arterial blood pressure (ABP) waveforms were analyzed. Mean ICP and ABP were calculated from consecutive 10 s periods. Pressure-reactivity index (PRx) were further derived with calculations performed every 10 s. Thus formed time series were then subject to algorithm of MSE and producing a value Complexity Index (CI) for each series. The relationship between derived parameters and dichotomized outcome was examined.
There were significant differences across groups classified by Glasgow Outcome Score in ICP, PRx, and CI of ICP (P < 0.0001; P = 0.001; P < 0.0001, respectively). For dichotomized survival/death and favorable/unfavorable outcome, CI of ICP achieved the strongest statistical significance (F = 28.7; P < 0.0001 and F = 17.21; P < 0.0001, respectively). CI of ICP was identified as a significant independent predictor of mortality and favourable outcome in a multivariable logistic regression model (P < 0.0001).
We demonstrated that complexity of ICP slow waves assessed by MSE was significantly associated with outcome in TBI patients.
Hornero R, et al. Crit Care Med 2006;34:87-95.Burr RL, et al. IEEE Trans Biomed Eng 2008;55:2509-18.
© 2012 European Society of Anaesthesiology