Aims & Objectives:
Pressure-reactivity index (PRx) has been widely studied as a surrogate marker of cerebral autoregulation in adults with traumatic brain injury (TBI). Raised intracranial pressure (ICP) and PRx >0.3 are associated with adverse neurological outcomes in TBI. Prospective studies in adults are evaluating an individualised optimum cerebral perfusion pressure (CPPopt) strategy based on PRx monitoring. Much less is known about patterns of autoregulation impairment in paediatric TBI.
To describe the patterns of ICP and PRx measurements in paediatric TBI patients.
Retrospective analysis of prospectively collected neuromonitoring data using ICM+ software (Cambridge enterprises, UK). Using minute by minute paired ICP and PRx values from first 48 hour period, the neuromonitoring observations were categorised into one of four ICP-PRx groups (combinations of high/low ICP and high/low PRx based on threshold values of 20mmHg for ICP and 0.3 for PRx).
30962 paired ICP and PRx observations from 15 patients were analysed. Median (IQR) ICP was 16 (12–21) and median PRx was -0.14 (-0.40, +0.16). Overall 28.7% of ICP readings were above 20mmHg and 16.5% of PRx readings were above 0.3. ICP-PRx distribution showed significant variation between patients (Table). Low ICP & low PRx was the most frequent pattern with high ICP& high PRx being the least common pattern.
A CPPopt approach has the greatest potential to improve outcome in the context of a high ICP & high PRx combination, which is found in the majority of monitored patients but occupies a small proportion of monitoring time.