Therapeutic hypothermia after out-of-hospital cardiac arrest in children

Abstract

Background: Therapeutic hypothermia is recommended for comatose adults after witnessed out-of-hospital cardiac arrest, but data about this intervention in children are limited.

Methods: We conducted this trial of two targeted temperature interventions at 38 children's hospitals involving children who remained unconscious after out-of-hospital cardiac arrest. Within 6 hours after the return of circulation, comatose patients who were older than 2 days and younger than 18 years of age were randomly assigned to therapeutic hypothermia (target temperature, 33.0°C) or therapeutic normothermia (target temperature, 36.8°C). The primary efficacy outcome, survival at 12 months after cardiac arrest with a Vineland Adaptive Behavior Scales, second edition (VABS-II), score of 70 or higher (on a scale from 20 to 160, with higher scores indicating better function), was evaluated among patients with a VABS-II score of at least 70 before cardiac arrest.

Results: A total of 295 patients underwent randomization. Among the 260 patients with data that could be evaluated and who had a VABS-II score of at least 70 before cardiac arrest, there was no significant difference in the primary outcome between the hypothermia group and the normothermia group (20% vs. 12%; relative likelihood, 1.54; 95% confidence interval [CI], 0.86 to 2.76; P=0.14). Among all the patients with data that could be evaluated, the change in the VABS-II score from baseline to 12 months was not significantly different (P=0.13) and 1-year survival was similar (38% in the hypothermia group vs. 29% in the normothermia group; relative likelihood, 1.29; 95% CI, 0.93 to 1.79; P=0.13). The groups had similar incidences of infection and serious arrhythmias, as well as similar use of blood products and 28-day mortality.

Conclusions: In comatose children who survived out-of-hospital cardiac arrest, therapeutic hypothermia, as compared with therapeutic normothermia, did not confer a significant benefit in survival with a good functional outcome at 1 year. (Funded by the National Heart, Lung, and Blood Institute and others; THAPCA-OH ClinicalTrials.gov number, NCT00878644.).

Figure 1. Enrollment, Randomization, and Treatment

Scores on the Glasgow Coma Scale (GCS) motor-response subscale range from 1 to 6, with lower scores indicating reduced levels of function. Scores on the Pediatric Overall Performance Category (POPC) and Pediatric Cerebral Performance Category (PCPC) scales range from 1 to 6, with lower scores indicating less disability. Scores on the Vineland Adaptive Behavior Scales, second edition (VABS-II), range from 20 to 160, with higher scores indicating better function. CNS denotes central nervous system, ICU intensive care unit, ITT intention to treat, and THAPCA Therapeutic Hypothermia after Pediatric Cardiac Arrest.

Figure 2. Temperature of Patients during 120 Hours of Targeted Temperature Management, According to Treatment Group

The temperature curves show the means of all primary temperature readings within each time interval (for example, all primary temperature readings from 22 to 26 hours after the initiation of treatment are counted in the category “24 hours since initiation of treatment”). The I bars indicate ±2 SD from the mean temperature within each time interval. Time points for normothermia are slightly shifted to prevent overlap. Temperatures recorded after early termination of treatment are not included in this analysis.