Citation

Gao L, Smieleweski P, Czosnyka M, Ercole A. J. Neurotrauma 2017; 34(19): 2743-2752.

Affiliation

Cambridge University, Division of Anaesthesia, Box 93 , Box 93 Addenbrooke's Hospital, , Hill's Road , CB2 0QQ , Cambridge, Cambridgeshire, United Kingdom of Great Britain and Northern Ireland , CB2 0QQ ; ae105@cam.ac.uk.

Copyright

(Copyright © 2017, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2016.4787

PMID

28330412

Abstract

The brain and heart are two vital systems in health and disease, increasingly recognised as a complex, interdependent network with constant information flow in both directions. After severe traumatic brain injury (TBI), the causal, directed interactions between the brain, heart and autonomic nervous system have not been well established. Novel methods are needed to probe unmeasured, potentially prognostic information in complex biological networks that are not revealed via traditional means. In this study, we examined potential bi-directional causality between intracranial pressure (ICP), mean arterial pressure (MAP) and heart rate (HR) and its relationship to mortality in a 24-hour period early after TBI. We applied Granger causality (GC) analysis to cardio-cerebral monitoring data from 171 severe traumatic brain injury patients admitted to a single neurocritical care center over a ten-year period. There was significant bi-directional causality between ICP and MAP, MAP and HR, ICP and HR in the majority of patients (p < 0.01). MAP influenced both ICP and HR to a greater extent (higher GC, p < 0. 00001), but there was no dominant unidirectional causality between ICP and HR (p = 0.85). Those who died had significantly lower GC for ICP causing MAP and HR causing ICP (p = 0.006 and p = 0.004 respectively) and were predictors of mortality independent of age, sex and traditional intracranial variables (ICP, cerebral perfusion pressure, GCS and PRx). Examining the brain and heart with GC-based features for the first time in severe TBI patients has confirmed strong interdependence, and reveals a significant relationship between select causality pairs and mortality. These results support the notion that impaired causal information flow between the cerebrovascular, autonomic and cardiovascular systems are of central importance in severe TBI.

Language: en

Keywords

ASSESSMENT TOOLS; INTRACRANIAL PRESSURE; SECONDARY INSULT; TRAUMATIC BRAIN INJURY