Effective methods of in-line intravenous fluid warming at low to moderate infusion rates

Three methods of warming intravenous (IV) fluids were examined. An in-line blood warmer was generally ineffective at flow rates of < 250 mL/hr but did produce temperatures of 30 to 31 degrees C at the catheter when the infusion rate was 500 to 1,000 mL/hr and the tubing was insulated. An in-line hot water bath produced temperatures of > or = 30 degrees C at flow rates of 200 to 1,000 mL/hr with uninsulated tubing. The addition of insulation maintained on infusate temperature of > or = 30 degrees C at a rate of 100 mL/hr. Application of a K-Thermia pad to the IV tubing close to the patient maintained an infusate temperature of > or = 30 degrees C at rates of 50 to 200 mL/hr. Warming at rates of 200 to 1,000 mL/hr is most effective with an in-line hot water bath. Warming at low infusion rates is best accomplished with a K-Thermia pad. The use of in-line blood warmers for routine fluid warming is ineffective.