ENTROPY OF INTRACRANIAL PRESSURE

FERNANDO POSE; FERNANDO GOLDENBERG; FRANCISCO REDELICO; CHRISTOS LAZARIDIS; ALI MANSOUR; NICOLAS CIARROCCHI; CHRISTOPHER KRAMER

Atlanta

Simposio; The 39th Annual Symposium of the National Neurotrauma Society, including the AANS/CNS Joint Section on Neurotrauma and Critical Care; 2022

The National Neurotrauma Society

Background: A reduction intracranial pressure (ICP) waveform complexity has been reported during intracranial hypertension in pa- tients with acute brain injury. The domain of non-linear dynamics can be utilized to explore complexity of such physiologic phenomena. One such analysis is entropy which ultimately describes the system?s random behavior or unpredictability.Objective: We compare different ICP waveform entropy derivations in a porcine model of intracranial hypertension (ICHTN) . Specifically we explore: Sample Entropy (SampEn), Approximate Entropy (ApEn), Permutation Entropy (PEn) and Wavelet Entropy (WEn).Methods: We previously developed a porcine model of intracranial hypertension. ICHTN is achieved by the gradual inflation of a cerebral intraparenchymal foley catheter while concomitantly recording ICP through an intraparenchymal pressure monitor. All four entropy calcula- tions were computed during 16 episodes where ICHTN was induced and then reversed by deflation of the foley catheter balloon. We recorded times from balloon inflation to the decrease in each entropy (DB), as well as the time from of entropy change to the time ICP reached 20 mmHg (DP).Results: At baseline (before ICHTTN), the mean and standard devi- ation for each entropy was: 0.23(0.01) WEn; 0.07(0.01) PEn; 0.08(0.01) SampEn; 0.03(0.06), ApEn. During ICHTN, DB times(s) were: 79(16) WEn; 184(73) PEn; 286(95) SampEn; 288(89) ApEn, and DP times(s) were 290(68) WEn; 185(69) PEn; 83(24) SampEn; 81(21) ApEn.Conclusions: WEn demonstrates the fastest change in association with ICHTN. Physiologically, it is related to the ICP pulse waveform. The role of WEn as a predictor for ICHTN is promising and warrants further investigation.