Christine M. Parmentier
Center for Devices and Radiological Health, Food and Drug Administration
Infusion pumps are microprocessor equipped devices used to regulate flow rate of hydration solutions, blood products, and medications delivered to patients in a variety of settings including hospitals, outpatient clinics, and even the home. The literature related to infusion pumps often cites programming errors as typifying the kind of use error associated with this medical device. While this type of error is one that is often reported through the FDA's MedWatch adverse event reporting system, it is not the only use error associated with infusion pumps. Numerous adverse events of inaccurate fluid delivery occurring with infusion pumps are causally linked to an incorrect connection between the infusion pump and the administration set and tubing that delivers the solution to the patient. This incorrect tubing placement is also referred to as misloading.
In many settings where the infusion pump is used, with the exception of the home setting perhaps, the nurse is often the health care provider who has the primary responsibility of administering infusion therapy for the patient. The nurse connects the container with the solution to be delivered to the infusion administration set and tubing, attaches this administration set to the pump and the patient, programs the pump, monitors the delivery of solution to the patient, and discontinues the delivery of solution when the treatment is completed.
Many infusion pumps use standardized administration sets and tubing. A linear peristaltic pumping mechanism propels fluid through the tubing. The tubing is stretched across the pump head where the pumping "fingers" come in contact with the tubing (see illustration) and as each successive pumping finger squeezes the tubing against the backplate, the fluid contained in the tubing is pushed along in a peristaltic fashion. When tubing is not correctly in place within the tubing channel, the pumping fingers are not able to compress the tubing, or do so only partially, resulting in altered fluid delivery.
One type of pump, for example, is associated with two different types of misloadings which result in different fluid delivery outcomes: a siphoning of fluid in the line and blood rom the patient backwards through the tubing, or inaccurate fluid delivery.
To minimize the potential for infusion pump misloading, all of the factors associated with the device, the environment and the user, as well as their interactions, must be considered during the design of the device.