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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.

Background. Cardiac arrest is a potentially devastating event, associated with death or severe neurological complications in survivors. There is little evidence on paediatric cardiac arrest prevalence, characteristics and outcomes in South Africa (SA).Objective. To describe the characteristics, course and outcomes of children admitted to an SA paediatric intensive care unit (PICU) following cardiac arrest.Methods. Retrospective descriptive study of routinely collected data (January 2010 - December 2011).Results. Of 2 501 PICU admissions, 110 (4.4%) had preceding cardiac arrest. The median (interquartile range (IQR)) age of children was 7.2 (2.5 - 21.6) months. In-hospital arrests accounted for 80.6% of the events. The most common primary diagnostic categories were respiratory (29.1%), cardiovascular (21.4%) and gastrointestinal (21.4%). Twenty-four patients (23.3%) arrested during endotracheal intubation. Cardiopulmonary resuscitation (CPR) was applied for a median (IQR) of 10 (5 - 20) minutes. Duration of CPR for non-survivors and survivors was 17.5 (10 - 30) v. 10 (5 - 15) minutes (p=0.006). PICU mortality was 38.8%, with half of the deaths occurring within 24 hours of admission. The standardised mortality ratio was 0.7. The median (IQR) length of stay in the PICU and hospital was 3 (1 - 8) and 27 (9 -52) days, respectively. No independent predictors of mortality were identified. Thirty-nine surviving patients (76.5%) had normal neurological function or mild disability at follow-up after hospital discharge. Six (11.8%) survived with severe disability.Conclusion. Mortality was lower than predicted in children admitted to the PICU following cardiac arrest. The majority of survivors had good neurological outcomes.Keywords. Pediatric, cardiac arrest, cardiopulmonary resuscitation, pulseless electrical activity, ventricular tachycardia, pediatric intensive care unit, in-hospital cardiac arrest, out-of-hospital cardiac arrest