The role of cardiovascular response as a predictor of neurologic disability in children with brain injury – a pilot study

Objective

We aimed to assess medium-to long-term neurological outcomes in children with severe acute brain injury (ABI) and to identify cardiovascular predictors associated with unfavorable outcomes, such as heart rate (HR), blood pressure (BP), and heart rate variability (HRV). HRV refers to the oscillations in the intervals between consecutive heartbeats, reflecting the dynamic interplay between sympathetic and parasympathetic impulses to the heart. It provides a non-invasive indicator of autonomic nervous system (ANS) activity.

Design

Prospective observational cohort.

Setting

Tertiary academic pediatric intensive care unit (PICU).

Patients

Children >27 days and <18 years old admitted to the PICU after severe ABI who survived to PICU discharge. Children suspected of being brain dead at PICU admission or with cardiac arrythmias were excluded.

Interventions

None.

Measure

ments: Physiological variables, neurological data, chemistry and hematologic tests and medication were collected within the initial 12 h following admission to the PICU. Linear and nonlinear indices of HRV obtained from electrocardiogram (ECG) Holter recordings, computerized tomography (CT) and PICU scores, as well as survival rates within the PICU, were evaluated. The primary outcome measure was global functional outcome as measured by the Pediatrics Glasgow Outcome Scale Extended (GOSE-Peds) at 3 and 12 months after injury. These data were taken by reviewing the medical records. The outcome was dichotomized into favorable and unfavorable based on predefined cutoffs. None to mild disability (GOSE-E PEDS category ≤2) was categorized as favorable outcome, whereas moderate to severe disability was categorized as unfavorable (GOSE-E PEDS category ≥3).

Main results

Thirty-one children with ABI were eligible for the study. Twenty-four were male (77.4 %) and they had the median age of 11.3 years old (IQR 5.6–14.3). Twenty-two (71.0 %) patients had traumatic brain injury (TBI) and five (16.1 %) cerebral hemorrhage. Sixteen children (51.6 %) had a favorable outcome at 3 months and twenty-one (67.7 %) at 12 months. The presence of tachycardia or bradycardia was not related to the prognosis. Patients with systolic arterial blood pressure (SBP) above the 95th percentile in the first 12 h after admission to the PICU exhibited a significantly better neurological outcome [15 (68.2 %) vs. 9 (31.8 %), p = 0.006] at 3 months, and [20 (83.3 %) vs. 4 (16.7 %), p = 0.002] at 12 months. Calculated HRV values were higher, both on admission and 12 h after admission, in patients with a favorable prognosis at 3 and 12 months. However, these results were statistically significant only for RMSSD, LF, TP, and Poincaré SD1 and SD2 at 12 h after admission and for outcomes at 3 months. Patients with LF > 70.0 ms² at 12 h after admission had a significantly better outcome at 12 months [11.0 (91.7 %) vs 1.0 (8.3 %), p = 0.046]. 87.5 % of patients with SDNN >35.0 ms and 70.5 % of patients with RMSSD >3.2 ms, at 12 h after admission, showed a statistically significative better outcome at 3 months. Patients who had a more unfavorable prognosis spent significantly more time on mechanical ventilation and had a longer length of stay (LOS) in the PICU.

Conclusions

This study suggests that elevated early SBP and HRV indices—particularly LF power measured 12 h after PICU admission—may serve as independent, non-invasive predictors of long-term neurological outcomes in children with severe ABI. These findings support the role of early autonomic activation as a marker of favorable prognosis and underscore the potential value of incorporating cardiovascular and autonomic monitoring into prognostic models and individualized neuroprotective strategies in pediatric neurocritical care.