A new method of continuous venovenous rewarming

Hypothermia is a significant problem in medicine and is part of a deadly triad, including hypothermia, acidosis, and coagulopathy. Multiple methods of rewarming are used to treat moderate hypothermia. The purpose of this study was to compare the effectiveness of continuous venovenous rewarming (CVVR) using the FMS 2000 (Belmont Instrument Corp., Billerica, Massachusetts) in conjunction with external rewarming techniques versus external rewarming alone in the porcine model.

Ten subject animals, each weighing approximately 40 kg, were evenly divided and randomly assigned to either a control group using external rewarming techniques alone or the CVVR group utilizing the FMS 2000 in addition to the external rewarming techniques used in the control group. Hypothermia was induced in the swine model using cold water immersion to achieve a core temperature of 30 degrees C. Both esophageal and rectal temperature probes were used to monitor and record core body temperatures every 15 minutes during the experiment. Each study animal was then rewarmed until a core temperature of at least 37 degrees C was recorded in both the esophageal and rectal probes. The animals were observed clinically for 3 days after the study.

The average time required to rewarm the control group was 253 minutes, compared with 113 minutes in the CVVR group. After 30 minutes of rewarming, the difference between the 2 groups with respect to core temperature was statistically significant (p = 0.002). A drop in core temperature after the initiation of rewarming, or after-drop, was noted in the control group animals, but not in the CVVR group. This difference was statistically significant after 15 minutes of rewarming (p = 0.015)

Venovenous rewarming utilizing the FMS 2000 fluid management system is more effective than is standard therapy alone for rewarming in the moderately hypothermic porcine model. This finding may prove clinically useful in the treatment of patients suffering from moderate hypothermia.