Abstract 106: Surface Cooling Induced Therapeutic Hypothermia Following Pediatric Cardiac Arrest
Introduction: Induced therapeutic hypothermia protocols following clinical pediatric cardiac arrest have not reported efficacy or compared core temperature (T) monitoring sites. An effective cooling protocol is necessary before outcome trials can be performed.
Hypothesis: Therapeutic hypothermia to goal range 32–34C for 24 hours will be maintained with overshoot hypo-or hyperthermia in <10% of values, using a standardized surface cooling protocol. Further, T monitored from rectum, esophagus and foley will equivalently reflect core body T.
Methods: With IRB approval and parental consent, 5 patients were cooled by standard protocol to goal rectal T 32–34 C using ice packs and servo controlled cooling blanket, with prospectively designated rescue protocols. T’s were recorded every 30 min from rectum, esophagus, foley and skin. Overshoot hypothermia was defined as T < target range and overshoot hyperthermia was defined as T > target range during cooling maintained for 24 hours. Excellent T stability was prospectively defined as <10% T values outside range. Data reported median [range]. Analysis by Kruskal-Wallis, Wilcoxon Rank Sum, and Spearman rank correlation for differences between T modalities.
Results: Of 1613 T measurements, 854 were during 32–34C maintenance. Time to achieve rectal T 34C was 1 [0,6] hour from initiation of cooling and 7 [1.5,9.5] hours from arrest. During maintenance, rectal T showed overshoot hypothermia <32C in 44 (21%) measures, overshoot hyperthermia >34C in 14 (7%) measures, and within goal 32–34C in 149 (72%). There was no significant difference between rectal 33.7 °C [30.3, 37.8] T, esophageal 34.1 °C [30.2, 37.9] T and foley 33.6°C [30.4, 37.9] T, but each were significantly different from skin 33.1C [28.2, 37.9] T (p<0.005). Rectal T correlated well with esophageal (R2 = 0.96 , p<0.001) and foley (R2 = 0.98, p<0.001) T sites.
Conclusions: This clinical pediatric cardiac arrest surface cooling protocol can rapidly induce hypothermia. During maintenance, overshoot hypothermia is common (>20%), but overshoot hyperthermia is rare (<10%). During surface cooling, rectal, esophageal, and foley T’s are equivalent to assess core T, but significantly higher than skin T.