Two unconscious patients with unknown past medical histories were found to be severely hypothermic, with core temperatures of 80.2°F and 86.7°F, respectively. During the course of active internal rewarming, both patients sustained a cardiac arrest. Emergency throacotomies were immediately done, and internal cardiac massage with warmed mediastinal irrigation was performed. Spontaneous cardiac activity developed in both patients. Within 24 hours after resuscitation, both patients were responsive and following commands.