Iced vs room-temperature injectates for cardiac index measurement during hypothermia and normothermia.
BACKGROUND
Few data are available on the accuracy of thermodilution measurements of cardiac index with room-temperature injectates and a closed delivery system in patients with low cardiac indexes and/or hypothermic body temperatures.


OBJECTIVE
To compare iced and room-temperature injectates for thermodilution measurement of cardiac index in postoperative cardiac surgical patients during hypothermia and normothermia.


METHODS
In a convenience sample of cardiac surgical patients in a cardiac recovery unit, cardiac index was measured with both room-temperature and iced injectates during hypothermia (< or =36.0 degrees C) and normothermia (> or =36.1 degrees C and < or =38.0 degrees C). Device bias and precision were calculated and graphed by using the Bland-Altman method. A Student t test was used to determine differences between cardiac indexes by injectate temperature.


RESULTS
A total of 38 patients were studied. Mean bias and precision for room-temperature and iced injectates in all patients were 0.11 (SD, 0.27) during hypothermia and -0.03 (SD, 0.21) during normothermia. In hypothermic patients, cardiac index differed significantly between room-temperature and iced injectates (t(1,37) = 2.41, P = .02). Cardiac index measurements did not differ between room-temperature and iced injectates in normothermic patients (P = .33).


CONCLUSIONS
Although significant differences in thermodilution cardiac index were found between room-temperature and iced injectates during hypothermic body temperatures, these differences were small (mean, <0.11). These findings add to the results of the few studies on accuracy of room-temperature injectates for thermodilution measurement of cardiac index.
Walsh
Elissa
E
Providence St Vincent's Medical Center, Portland, Oregon 97225, USA. Elissa.walsh@providence.org
Adams
Sheila
S
Chernipeski
Janine
J
Cloud
Jenny
J
Gillies
Elizabeth
E
Fox
Robert
R
Luckeroth
Patti
P
Rice
Marsha
M
Salamanca
Cora
C
Sherman
Betty
B
Nezworski
Andrea
A
Ash
Tracey
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures; D003080:Cold Temperature; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods*; D013815:Thermodilution / Q000379:methods