Implications of neurophysiological parameters in persons with severe brain injury with respect to improved patient outcomes: A retrospective review

Abstract

Primary objective: To determine whether neurophysiologic parameters—intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), partial brain tissue oxygenation (PbtO₂) and pressure reactivity index (PRx, calculated)—captured during the management of traumatic brain injury (TBI) have a relationship to patient outcome.

Research design: A retrospective analysis of neurophysiologic data collected from persons under medical management of TBI per Conemaugh Memorial Medical Center (CMMC) standard treatment algorithms.

Methods and procedures: Nine patients’ medical records that matched International Statistical Classification of Diseases and Related Health Problems (ICD-9) code for head injury and a Current Procedural Terminology (CPT) code for an ICP monitoring device or ventriculostomy were analysed on the aforementioned parameters.

Main outcomes and results: Statistical significance by mortality (α = 0.05) was found for ICP, CPP and PbtO₂. PRx showed a pattern of significance over the last 72 hours. The couplets (CPP & ICP) and (CPP & MAP) demonstrated significant correlations.

Conclusions: Improved autoregulation was associated with PRx values near zero. Controlling those parameters that affect PRx, namely MAP, ICP and CPP and more importantly cerebral oxygen perfusion (COP), would likely increase the probability of a better outcome while guarding against secondary insult.

• Pressure reactivity index
• autoregulation
• cerebral perfusion pressure
• intracranial pressure
• cerebral oxygen perfusion
• mean arterial pressure
• TBI
• ICP
• CPP
• MAP
• COP
• PRx