FACTORS AND METHODOLOGY IN ACHIEVING IDEAL DELIVERY TEMPERATURES FOR INTRAVENOUS AND LAVAGE FLUID IN HYPOTHERMIA

A study was undertaken to determine the relationship between temperatu re and delivery rate of warmed intravenous fluid using standard intrav enous infusion equipment and tubing. One-liter bags of 0.9% NaCl were warmed to 60 degrees C and run through standard microdrip tubing for 1 hour at rates of 1,000, 800, 600, and 400 mL/h. Thermistor probes wer e placed into the bag and into the tubing at 0, 100, 180, 230, and 280 cm from the intravenous bag, Separate fluid bags were also warmed to 39.3 degrees and 75 degrees C, and the fluid was run through the same apparatus at 1,000 mL/h and 200 mL/h, respectively. Temperatures were recorded at each site at the start of the infusion and every 10 minute s thereafter for 1 hour. Subsequently, 60-mL syringes of fluid warmed to 39.5 degrees C were eluted through 50 cm tubing over 10 minutes at 300 mL/h and 360 mL/h. Mean delivery temperature over each 10-minute i nfusion was determined. Fluid preheated to 39.3 degrees C approached r oom temperature at delivery even at a flow rate of 1,000 mL/h and tubi ng lengths as short as 100 cm. Fluid preheated to 60 degrees C was del ivered at near 37 degrees C using tubing lengths as long as 280 cm whe n eluted at 1,000 mL/h. Fluid preheated to 39 degrees C in 60-mL syrin ges and eluted through 50 cm of tubing over a period of 10 minutes at 300 mL/h or 360 mL/h was delivered near a mean temperature of 37 degre es C, These results show that warmed fluid can be delivered through st andard intravenous tubing at or near 37 degrees C if the fluid is preh eated to 60 degrees C and eluted through long tubing (280 cm) at high flow rates (1,000 mL/h). Alternatively, fluid warmed to 37 degrees C t o 42 degrees C can be delivered at or near 37 degrees C via intermitte nt bolus through short tubing (50 cm) either by hand or syringe pump. The latter approach would be particularly beneficial in the pediatric population, in whom it is not advisable to administer fluid at flow ra tes as high as 1,000 mL/h. Copyright (C) 1997 by W.B. Saunders Company .