Water Bath Fluid Warmers: What are the Risks?

The Centers for Disease Control and Prevention (CDC) estimates that each year, approximately 2 million patients admitted to acute-care hospitals in the United States acquire infections that were not related to the condition for which they were hospitalized. These infections result in approximately 90,000 deaths, and add $4.5 billion per year to healthcare costs.1

One potential source of nosocomial pathogens has garnered considerable attention water bath fluid warmers. In addition to susceptibility to bacteria growth when not properly maintained, defects in tubing of water bath fluid warmers have been found to cause the fluid in the reservoir to become mixed with blood, creating a potential for cross contamination.2

Potential Pathogenic Bacteria Transfer

In 1999, an investigation at a major U.S. metropolitan healthcare facility uncovered a possible connection between water bath fluid warmers and surgical infections.3 As part of this investigation, the researcher observed that open ports on the water bath fluid warming unit allowed water to spray out when the disposable IV connector was connected or disconnected to the warming unit, potentially contaminating the clinicians hands and/or the operating room environment.3

In addition, defects in the tubing of water bath warmers can cause leakage of the water bath solution directly into the patient via intravenous (IV) lines.4 In one reported case, a nurse anesthetist reported that a patient received approximately 750 mL to 1,000 mL of water intravenously when water from a fluid warmer mixed with the intravenous solution.4 The transmission resulted from a defect in the fluid warmer tubing.

Guidelines Recommend Against Water

The CDC issued Guidelines for Environmental Infection Control in Health- Care Facilities. One notable recommendation of these guidelines is the suggestion that facilities remove potential sources of contaminated water whenever possible.5 The guidelines note, Moist environments and aqueous solutions in healthcare settings have the potential to serve as reservoirs for waterborne microorganisms. Under favorable environmental circumstances (e.g., warm temperature and the presence of a source of nutrition), many bacterial and some protozoal microorganisms can either proliferate in active growth or remain for long periods in highly stable, environmentally resistant (yet infectious) forms.

Avoiding Potential Infection Risks

Dry heat warming devices use metal plates within the unit to warm intravenous fluids. Disposable sets are inserted into the unit and the IV fluids flow through the sets, warming them prior to reaching the patient. No water. No risk of water-related infection.

Although dry heat technology represents a significant advancement in blood/fluid warming, dry heat systems dont all function exactly the same way. Some dry heat fluid warmers heat erratically and can overheat or under heat infused fluids when flow rates change rapidly. Because of this, healthcare practitioners should ensure that any dry heat technology they use is optimized for maximum heat transfer along the entire range of flow rates to avoid this issue.

Arizant Healthcare Inc. pioneered the concept of forced-air patient warming with the introduction of the Bair Hugger® therapy in 1987. Today, the company continues to develop ground-breaking temperature management products like the Ranger® blood/fluid warming system with SmartHeat® technology and the Bair Paws® system.


1. Centers for Disease Control and Prevention. Healthcare-Associated Infections. Accessed at: http://www.cdc.gov/ncidod/dhqp/healthDis.html, 2006.

2. Doyle, DJ, et al. Failure of an IV fluid warming device. Can J Anesthesia. April 2007. See also: Rutala W A and Weber DJ. Water as a reservoir or nosocomial pathogens. Infection Control Hosp Epidem. September 1997; 18: 609-616.

3. Burns S. An investigation of surgical infections reveals a fluid warmer as a reservoir for bacteria, American Journal of Infection Control (APIC), April 1999, 27:2, 216.

4. DAngelo E. Fluid warmer leakage into the bloodstream: A case report. J Am Assoc Nurse Anesthetists. December 1995.

5. Centers for Disease Control and Prevention. Guidelines for Environmental Infection Control in Health-Care Facilities. Recommendations of CDC and Healthcare Infection Control Practices Advisory Committee (HICPAC). 2003.