Specific Guidance 2.4: Infusion Pumps

Overview

An infusion pump infuses fluids into the circulatory system, a process known as Infusion Therapy. For the purpose of device regulation, an infusion pump is described in FDA regulation (21 CFR 880.5725) as:

"a device used in a health care facility to pump fluids into a patient in a controlled manner. The device may use a piston pump, a roller pump, or a peristaltic pump and may be powered electrically or mechanically. The device may also operate using a constant force to propel fluid through a narrow tube which determines the flow rate. The device may include means to detect a fault condition, such as air in, or blockage of, the infusion line and to activate an alarm."

The fluids administered by these devices are medications and/or nutrients that are required by the patient. Medications include antibiotics, pain medicines, and chemotherapy drugs. Generally, the infusion is done intravenously. However, subcutaneous, arterial, and epidurals are also used.

Infusion pumps can be broken into four classes:

1. Volumetric Infusion Pumps - these pumps use pressure to propel the fluid at a desired flow rate.
2. Syringe Infusion Pumps - these are appropriate when small volumes of concentrated drugs must be delivered over an extended period of time (e.g., neonatal, infant, and critical care).
3. Patient Controlled Analgesia (PCA) - these electronically controlled pumps deliver a preprogrammed dosage to a patient when a button is activated (the patient is in control of delivery, but the clinician sets the dosage and a locked system is used to prevent over-usage).
4. Ambulatory Infusion Pumps - these are portable, lightweight, battery-operated pumps.
   

Example images of these four categories are provided in Figure 1.

Figure 1. Images of representative products for each of the four categories of infusion pumps: volumetric, syringe, patient-controlled analgesia, and ambulatory.

There is a wide range of acceptable programmable dosing parameters. The dosage rate can range from as low as 2 drops per hour to as high as over one liter per hour. Nutritional fluids tend to be infused in higher volumes whereas some drugs need to be infused at a much slower rate. General-purpose IV pumps have a very large dosing range, typically 10,000-fold. This helps explain why these use errors can be serious, and why the FDA is so concerned about the safety of these devices.

A common sequence of subtasks include all or most of the following:

1. Preparation of tubing (e.g., close the roller clamp on the tubing, and remove protective covering)
2. Prepare infusion fluid. Check labeling. Insert set’s spike into fluid container.
3. Allow drip chamber to fill. Remove air from tubing.
4. Insert tubing in channel to be used. When tubing is secured, close channel.
5. Enter rate value. Use the keypad to enter rate.
6. Enter volume to be infused.
7. Attach the administration set to the patient’s I.V. device.
8. Press the “start” key to begin infusion
9. At home users have preprogrammed dosages, but they are still responsible for properly operating the pumps. (This may include choosing the infusion task or just simply turning the device on to start the infusion.)

According to the FDA and other sources, the most common problem with infusion pump use is over- or under- infusion. According to a study done at Northwestern University, out of 389 observed errors, 37 were “rate deviation”, and “slip-of-the-finger” errors only occurred in three instances. According to CardinalHealth, Adverse drug events (ADEs) are the most common cause of patient injury in hospitals and 61 percent of the most serious and life-threatening adverse events are IV drug related. Other errors that have been recorded include incorrect medication, delay of rate or medication change, Dosing rates and fluid volume are consistently held up as the major concern in infusion therapy. Less frequent mistakes that relate to usability may be maintaining functional tubing (e.g., checking for kinks, proper set-up, etc). A recent trend has been "smart pumps" - these are the newest type of infusion pumps that offer dose calculation software as well as software for drug libraries, and are designed to identify and correct pumping errors.

It is is important that all persons with disabilities who could benefit from infusion therapy have such access; hence this specific guidance. Medication errors associated with infusion pumps are still common and continue to present potentially harmful problems. From a usability standpoint, the infusion pump interface should is our focus. Of note is that the buttons on infusion pumps are not fully accessible for many individuals with disabilities, and often do not follow general guidance provided in Section 1. For instance, most current products have moved to flat keypads with little to no tactile feedback, which violates General Guidance 1.1.6 - although the interfaces have continuously been redesigned to ensure ease of use for trained nurses and physicians, the flat keypads are not ideal for users that may have tremors are limited dexterity. Also, the alarms, which all pumps have, could be more accessible to all users. Currently they are dominantly auditory alarms with small “error” displays. This guidance is based in part on a human subjects study by Margaret "Peggy" Keane which used the MUA-Lab technology to study operation of 4 different infusion pumps by users with diverse abilities.

2.4.1

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2.4.2

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