New circulating-water devices warm more quickly than forced-air in volunteers.
BACKGROUND
Newer circulating-water systems supply more heat than forced-air, mainly because the heat capacity of water is much greater than for that of dry warm air and, in part, because they provide posterior as well as anterior heating. Several heating systems are available, but three major ones have yet to be compared directly. We therefore compared two circulating-water systems with a forced-air system during simulation of upper abdominal or chest surgery in volunteers.


METHODS
Seven healthy volunteers participated on three separate study days. Each day, they were anesthetized and cooled to a core temperature near 34 degrees C, which was maintained for 45-60 min. They were then rewarmed with one of three warming systems until distal esophageal core temperature reached 36 degrees C or anesthesia had lasted 8 h. The warming systems were 1) energy transfer pads (two split torso pads and two universal pads; Kimberly Clark, Roswell, GA); 2) circulating-water garment (Allon MTRE 3365 for cardiac surgery, Akiva, Israel); and 3) lower body forced-air warming (Bair Hugger #525, #750 blower, Eden Prairie, MN). Data are presented as mean +/- sd; P < 0.05 was statistically significant.


RESULTS
The rate of increase of core temperature from 34 degrees C to 36 degrees C was 1.2 degrees C +/- 0.2 degrees C/h with the Kimberly Clark system, 0.9 degrees C +/- 0.2 degrees C/h with the Allon system, and 0.6 degrees C +/- 0.1 degrees C/h with the Bair Hugger (P = 0.002).


CONCLUSIONS
The warming rate with the Kimberly Clark system was 25% faster than with the Allon system and twice as fast as with the Bair Hugger. Both circulating-water systems thus warmed hypothermic volunteers in significantly less time than the forced-air system.
Outcomes Research Institute, University of Louisville, Louisville, Kentucky, USA. anwadh01@louisville.edu
Anupama
A
Wadhwa
Ryu
R
Komatsu
Mukadder
M
Orhan-Sungur
Pamela
P
Barnes
JangHyeok
J
In
Daniel I
DI
Sessler
Rainer
R
Lenhardt
D000293:Adolescent; D000328:Adult; D000388:Air; D001831:Body Temperature / Q000502:physiology; D006801:Humans; D006875:Hydrotherapy / Q000295:instrumentation / Q000379:methods / Q000639:trends*; D008297:Male; D017694:Rewarming / Q000295:instrumentation / Q000379:methods / Q000639:trends*; D014867:Water
D014867:Water