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Cerebrovascular Pressure Reactivity Has a Strong and Independent Association With Outcome in Children With Severe
Claudia A Smith1,2, Ursula K Rohlwink1,2,3, Katya Mauff4
1Division of Neurosurgery, Department of Surgery, Red Cross War Memorial Children's Hospital, University of Cape Town, Cape Town, South Africa.
Insights
Cerebrovascular pressure reactivity index (PRx) in children with severe traumatic brain injury (sTBI) strongly predicts mortality and poor outcomes. This analysis of PRx in a large pediatric cohort highlights its potential for guiding clinical care.
Area of Science:
- Pediatric critical care medicine
- Neurocritical care
- Cerebrovascular physiology
Background:
- Severe traumatic brain injury (sTBI) in children presents complex management challenges.
- Assessing cerebrovascular pressure reactivity is crucial for understanding brain injury pathophysiology.
- The pressure reactivity index (PRx) offers a quantitative measure of cerebrovascular autoregulation.
Purpose of the Study:
- To investigate the cerebrovascular pressure reactivity index (PRx) in a large cohort of pediatric patients with sTBI.
- To determine the association between PRx and physiological variables, mortality, and patient outcomes.
- To evaluate PRx as a prognostic tool in pediatric sTBI.
Main Methods:
- Retrospective observational cohort study of pediatric sTBI patients (≤14 years) with intracranial pressure (ICP) monitoring.
- Calculation of PRx as a moving correlation coefficient between ICP and mean arterial pressure (MAP) using high-frequency data.
- Statistical analysis including correlation, multivariable logistic regression, and ROC curves to assess PRx associations with outcomes.
Main Results:
- The study analyzed over 1.7 million minutes of data from 196 children, with a mortality rate of 10.7%.
- PRx showed moderate positive correlation with ICP and moderate negative correlation with cerebral perfusion pressure (CPP).
- PRx was significantly higher in patients with poor outcomes and demonstrated a strong, independent association with mortality (ROC AUC = 0.91), with a threshold of 0.25 being optimal for predicting mortality.
Conclusions:
- This is the largest pediatric cohort study analyzing PRx to date.
- PRx is a strong, independent predictor of outcome in pediatric sTBI, irrespective of ICP, CPP, GCS, and age.
- Impaired autoregulation, as indicated by PRx, is a significant factor in poor outcomes and may inform clinical management strategies.
Objectives:
To examine cerebrovascular pressure reactivity index (PRx) in a large cohort of children with severe traumatic brain injury (sTBI) in association with physiologic variables and outcome.
Design:
Retrospective observational cohort study.
Setting:
Red Cross War Memorial Children's Hospital in Cape Town, South Africa.
Patients:
Pediatric (≤ 14 yr old) sTBI patients with intracranial pressure (ICP) monitoring (postresuscitation Glasgow Coma Score [Glasgow Coma Scale (GCS)] of ≤ 8).
Measurements And Main Results:
Data were analyzed from ICM+ files sampled at 100Hz. PRx (a mathematical indicator of pressure reactivity) was calculated as a moving correlation coefficient between ICP and mean arterial pressure (MAP) as previously described. Associations between PRx, age, GCS, ICP, MAP, and cerebral perfusion pressure (CPP) were examined with summary measures and correlation analysis using high-frequency data. Associations between PRx and mortality/outcome were examined with multivariable logistic regression analysis and the prognostic ability of PRx with receiver operating characteristic (ROCs) curves. The dataset included over 1.7 million minutes (28,634 hr) of MAP and ICP data in 196 children. The series mortality was 10.7% (21/196), and unfavorable outcome 29.6% (58/196). PRx had a moderate positive correlation with ICP ( r = 0.44; p < 0.001), a moderate negative correlation with CPP ( r = -0.43; p < 0.001), and a weak negative correlation with MAP ( r = -0.21; p = 0.004). PRx was consistently higher in patients with poor outcome and had a strong, independent association with mortality (ROC area under the curve = 0.91). A PRx threshold of 0.25 showed the best predictive ability for mortality.
Conclusions:
This is the largest cohort of children with PRx analysis of cerebrovascular reactivity to date. PRx had a strong association with outcome that was independent of ICP, CPP, GCS, and age. The data suggest that impaired autoregulation is an independent factor associated with poor outcome and may be useful in directing clinical care.
