Pressure Reactivity Index - Daily in Pediatric Traumatic Brain Injury

Purpose Pressure Reactivity Index (PRx) is a measure of cerebral autoregulation that is associated with outcomes in pediatric traumatic brain injury. It is a resource-intensive tool that is not universally available. This study aims to assess the association of a novel low-resolution index derived from the same physiological inputs as the PRx, termed the Pressure Reactivity Index-Daily (PRx-D), with outcomes in children with traumatic brain injury (TBI). Methods This is a secondary analysis of the Approaches and Decisions in Acute Pediatric Traumatic Brain Injury (ADAPT), an international multi-institutional comparative effectiveness trial that enrolled children from 2014-2017 who received intracranial monitoring for severe traumatic brain injury (Glasgow Coma Scale < 9). One thousand patients under 18 years of age were enrolled in the ADAPT trial. PRx-D was calculated using the Spearman correlation coefficient of hourly mean arterial pressures (MAP) and intracranial pressures (ICP). One PRx-D value was calculated for every day of admission for seven days. The minimum, median, maximum and day 1 PRx-D were used in the analysis. The primary outcome variable was dichotomized Glasgow Outcome Scale Extended Peds (DGOSE), with 1-4 defined as favorable outcome and 5-8 defined as unfavorable outcome. The secondary outcome variable was hospital death. Results Higher values of median PRx-D, maximum PRx-D, and day 1 PRx-D were associated with unfavorable DGOSE in bivariate analysis. In multivariable analyses, higher maximum PRx-D (OR 2.45, 95% CI 1.25-4.82) was independently associated with unfavorable DGOSE. Higher median, minimum, maximum, and day 1 PRx-D were associated with hospital death in bivariate analysis. In multivariable analyses, higher minimum PRx-D, (OR 2.35, 95% CI 1.03-5.37) and median PRx-D (OR 4.34, 95% CI 1.42-13.23) were independently associated with hospital death. Conclusions PRx-D, a clinical measure that can be obtained in lower resource settings, is independently associated with outcome in children with severe TBI.