Shortening and superlon-wrapping the downstream tube can increase the useful range of the blood warmer.
BACKGROUND
Hypothermia occurs frequently in clinical anesthesia. Many apparatus were introduced to keep intravenous fluid warm. But at low to medium flow rates little effects have been achieved because of heat lost along the tube. Superlon, an industrial heat-preserving material widely used in air conditioning to prevent temperature change, has never been used in the blood warmer.


METHODS
The study was performed in three groups group I using standard (120 cm) unwrapped tube (Animac AM-4 set), group II using a shortened downstream tube (60 cm), and group III using the downstream tube which was further wrapped with superlon (Super LTD). The blood warmer used was identical in all 3 groups. We recorded the fluid temperatures at different points downstream at various flow rates. The values were then compared among groups.


RESULTS
The fluid temperatures before entering the warmer were around 20 degrees C and 37 degrees C at the 2 cm post-warmer points at various flow rates. The end point temperatures rose with flow rates and were the highest in group III and lowest in group I at each flow rate (p < 0.01). In group III the temperature could be kept above 32 degrees C at a very low flow rate (150 ml/h) and above 35 degrees C at 300 ml/h. In group I, 1,000 to 2,000 ml/h were needed to keep the same temperature.


CONCLUSIONS
These refinements increase the useful range of the Animac AM-4 warmer and make it useful in pediatric rapid fluid resuscitation and current fluid management. Moreover, they are easy to set up, inexpensive, and can be applied to any kind of blood warmers.
Tseng
C C
CC
Department of Anesthesiology, Medical College, National Cheng Kung University, Tainan, Taiwan, R.O.C.
Su
H B
HB
Yeh
F C
FC
Tsai
Y C
YC
Chang
D P
DP
Chang
C L
CL
D000758:Anesthesia; D001769:Blood; D006361:Heating / Q000295:instrumentation*; D006801:Humans; D013696:Temperature