Hypothermia for 24 hours after asphyxic cardiac arrest in piglets provides striatal neuroprotection that is sustained 10 days after rewarming

Pediatr Res. 2003 Aug;54(2):253-62. doi: 10.1203/01.PDR.0000072783.22373.FF. Epub 2003 May 7.


The neuroprotective effect of hypothermia instituted after resuscitation from asphyxic cardiac arrest has not been studied in immature brain, particularly in a large animal model with recovery periods greater than 4 d. Moreover, protection from severe hypoxia seen with 3 h of hypothermia was reported to be lost when hypothermic duration was extended to 24 h in unsedated piglets, in contrast to the neuroprotection reported by 72 h of intrauterine head cooling in fetal sheep. Piglets (5-7 postnatal days) were subjected to asphyxic cardiac arrest followed by 24 h of either hypothermia (34 degrees C) or normothermia (38.5-39 degrees C). Comparisons were made with normothermic and hypothermic surgical sham animals without asphyxia. All of these groups were sedated, paralyzed, and mechanically ventilated for the first 24 h to prevent shivering and possible depletion of glucose stores. Hypothermia per se did not cause remarkable structural abnormalities. Ischemic damage was evaluated in putamen at 1 d of recovery without rewarming and at 11 d (10 d +/- SD after rewarming). Ischemic cytopathology affected 60 +/- 12% of neurons in putamen of normothermic animals compared with 9 +/- 6% in hypothermic animals at 1 d of recovery without rewarming. At 11 d of recovery from hypoxia-ischemia, the density of viable neurons (neuron profiles/mm2) in putamen was markedly reduced in normothermic animals (81 +/- 40) compared with hypothermic animals (287 +/- 22), which was the same as in sham normothermic (271 +/- 21), sham hypothermic (288 +/- 46) and naïve animals (307 +/- 51). These data demonstrate that 24 h of hypothermia at 34 degrees C with sedation and muscle relaxation after asphyxic cardiac arrest prevents necrotic striatal neuronal cell death in immature brain before rewarming, and that the effect is sustained at 11 d after injury without deleterious side effects.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Disease
  • Animals
  • Asphyxia / mortality
  • Asphyxia / pathology
  • Asphyxia / therapy*
  • Behavior, Animal
  • Body Temperature
  • Corpus Striatum / pathology*
  • Corpus Striatum / physiology
  • Electroencephalography
  • Heart Arrest / mortality
  • Heart Arrest / parasitology
  • Heart Arrest / therapy*
  • Hot Temperature
  • Hypothermia, Induced*
  • Male
  • Necrosis
  • Rectum
  • Swine
  • Weight Gain