Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage?

Hasan B. Alam, Peter Rhee, Kaneatsu Honma, Huazhen Chen, Eduardo C. Ayuste, Tom Lin, Kevin Toruno, Tina Mehrani, Caroline Engel, Zheng Chen, Larry M. Gentilello, William B. Long, Frederick A. Moore, Lawrence H. Pitt, Hasan B. Alam

Research output: Contribution to journalArticlepeer-review

77 Scopus citations


Background: Rapid induction of profound hypothermic arrest (suspended animation) can provide valuable time for the repair of complex injuries and improve survival. The optimal rate for re-warming from a state of profound hypothermia is unknown. This experiment was designed to test the impact of different warming rates on outcome in a swine model of lethal hemorrhage from complex vascular injuries. Methods: Uncontrolled lethal hemorrhage was induced in 40 swine (80-120 Ibs) by creating an iliac artery and vein injury, followed 30 minutes later (simulating transport time) by laceration of the descending thoracic aorta. Through a thoracotomy approach, a catheter was placed in the aorta and hyperkalemic organ preservation solution was infused on cardiopulmonary bypass to rapidly (2°C/min) induce profound (10°C) hypothermia. Vascular injuries were repaired during 60 minutes of hypothermic arrest. The 4 groups (n = 10/group) included normothermic controls (NC) where core temperature was maintained between 36 to 37°C, and re-warming from profound hypothermia at rates of: 0.25°C/min (slow), 0.5°C/min (medium), or 1°C/min (fast). Hyperkalemia was reversed during the hypothermic arrest period, and blood was infused for resuscitation during re-warming. After discontinuation of cardiopulmonary bypass, the animals were recovered and monitored for 6 weeks for neurologic deficits, cognitive function (learning new skills), and organ dysfunction. Detailed examination of brains was performed at 6 weeks. Results: All the normothermic animals died, whereas survival rates for slow, medium and fast re-warming from hypothermie arrest were 50, 90, and 30%, respectively (p < 0.05 slow and medium warming versus normothermic control, p < 0.05 medium versus fast re-warming). All the surviving animals were neurologically intact, displayed normal learning capacity, and had no long-term organ dysfunction. Conclusions: Rapid induction of hypothermie arrest maintains viability of brain during repair of lethal vascular injuries. Long-term survival is influenced by the rate of reversal of hypothermia.

Original languageEnglish (US)
Pages (from-to)134-146
Number of pages13
JournalJournal of Trauma - Injury, Infection and Critical Care
Issue number1
StatePublished - Jan 2006


  • Hypothermia
  • Neurologic function
  • Organ preservation
  • Survival
  • Suspended animation
  • Thoracotomy
  • Uncontrolled hemorrhage
  • Vascular injuries
  • Warming rate

ASJC Scopus subject areas

  • Surgery
  • Critical Care and Intensive Care Medicine


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