Mild hypothermia after severe transient hypoxia-ischemia reduces the delayed rise in cerebral lactate in the newborn piglet

Pediatr Res. 1997 Jun;41(6):803-8. doi: 10.1203/00006450-199706000-00002.

Abstract

This study tested the hypothesis that mild hypothermia after severe transient hypoxia-ischemia reduces the subsequent delayed rise in cerebral lactate peak-area ratios as determined by proton (1H) magnetic resonance spectroscopy (MRS) in the newborn piglet. Nine piglets aged < 24 h underwent temporary occlusion of the common carotid arteries and hypoxemia. Resuscitation was started when cerebral [phosphocreatine]/[inorganic phosphate] had fallen close to zero and [nucleotide triphosphate (NTP)]/[exchangeable phosphate pool (EPP)] was below about a third of baseline. On resuscitation rectal and tympanic temperatures were lowered to 35 degrees C for 12 h after which normothermia (38.5 degrees C) was resumed. 1H MRS data collected over 48 or 64 h after resuscitation were compared with concurrently established data from 12 piglets similarly subjected to transient cerebral hypoxia-ischemia, but maintained normothermic, and six sham-operated controls. The severity of the primary insult (judged from the time integral of depletion of [NTP]/[EPP]) was similar in the hypothermic and normothermic groups. The maximum lactate/N-acetylaspartate ratio observed between 24 and 48 h after resuscitation in the hypothermic group was 0.10 (0.05-0.97), median (interquartile range), which was significantly lower than that observed in the normothermic group, 1.28 (0.97-2.14), and not significantly different from that observed in the control group, 0.08 (0.06-0.11). Similar results were obtained for lactate/choline and lactate/total creatine. We conclude that mild hypothermia after a severe acute cerebral hypoxic-ischemic insult reduces the delayed elevation in lactate peak-area ratios, thus reflecting reduced lactate accumulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Brain / metabolism*
  • Energy Metabolism*
  • Hydrogen
  • Hypothermia, Induced*
  • Hypoxia, Brain / metabolism*
  • Hypoxia, Brain / therapy*
  • Ischemic Attack, Transient / metabolism*
  • Ischemic Attack, Transient / therapy*
  • Lactates / metabolism*
  • Magnetic Resonance Spectroscopy
  • Phosphates / metabolism
  • Phosphocreatine / metabolism
  • Ribonucleotides / metabolism
  • Swine

Substances

  • Lactates
  • Phosphates
  • Ribonucleotides
  • Phosphocreatine
  • Hydrogen