- Software problems
- Alarm errors
- Inadequate user interface design (“human factors” issues)
- Broken components
- Battery failures
- Fire, sparks, charring, or shocks
- A software error message is displayed, stating that the pump is inoperable. This occurs in the absence of an identifiable problem.
- The infusion pump interprets a single keystroke as multiple keystrokes (a problem called a “key bounce”). For example, the user programs an infusion rate of 10 mL/hour, but the device registers an infusion rate of 100 mL/hour.
- The infusion pump fails to generate an audible alarm for a critical problem, such as an occlusion (e.g., clamped tubing) or the presence of air in the infusion tubing.
- The infusion pump generates an occlusion alarm in the absence of an occlusion.
Inadequate user interface design ("human factors" issues ):
- The design of the infusion pump screen confuses the user, or the infusion pump does not respond as it should (i.e., with a warning or alarm) when inappropriate data is entered.
- The infusion pump screen doesn’t make clear which units of measurement the user is expected to enter. For example, the user may enter weight in pounds when the infusion pump requires it in kilograms.
- Pump labels or components become damaged under routine use. For example, cleaning the pump, as the user-maintainer believes is acceptable practice, may damage the pump, making it unreliable for clinical use. Users with long fingernails may damage the print on the pump keys, making them unreadable.
- User instructions or cues for mechanical set-up are not specific or clear enough. For example, an instruction to attach a tubing set in all required tube holder-clips before closing the pump’s access door may be unclear, resulting in clamped tubing and under-infusion.
- Inadequately designed alarm functions and settings cause users to miss problems or respond late. For example, an alarm indicating low battery charge may not be displayed in time for a user to prevent pump shut-off during a critical infusion while a patient is in transport. False (“nuisance”) alarms may decrease users’ sensitivity to all alarms.
- The infusion pump screen design is clunky or confusing to users, causing a delay in therapy. For example, the “Start Infusion” key may be located next to the “Power” key, and a user may turn off the infusion pump instead of initiating infusion. In some cases, programmed settings are lost when a user turns the pump off, and the infusion settings have to be re-entered after the pump restarts.
- Warnings are displayed so often that users come to ignore them (similar to “nuisance alarms”), are not detailed enough to prevent misuse, or represent values in ways that are unfamiliar to the user.
- Warning messages are unclear. In the example below, it is unclear if the user is confirming the warning message or the infusion settings.
- User manuals are confusing, inadequate, outdated, or unavailable. This is particularly of concern for home-based users.
- When communicating the critical aspects of the pump’s operational, default, or “piggyback” status, the system does not use user-friendly language or does not give enough information to guide users through appropriate actions.
Graphic: Cracks between operating buttons allow water inside.
- The infusion pump may have been dropped or damaged during use, which may result in an over-infusion or an under-infusion if the pump continues to be used without being repaired.
- The plastic casing of an insulin pump, although promoted as waterproof, is prone to cracking, allowing water to enter the case and to cause the pump to malfunction. See Graphic on right.
- Slight misalignment of tubing places stress on the pump door, resulting in eventual cracking of pump case. See the photos below.
Photo: Sealed lead-acid battery damage caused by overcharging.
- A design issue causes over-heating of the battery and leads to premature battery failure. See photo on right.
- A patient returns from ambulating and forgets to plug in the infusion pump. The infusion pump alarms with a low battery message, but the speaker volume is set too low, and the alarm goes unnoticed. The infusion pump powers off after the battery is depleted.
- The battery is not replaced during the recommended end of life routine maintenance.
- The user plugs in or unplugs the device from an electrical outlet and receives a shock, and/or sparks are seen.
- A burning smell or flames are noted on the infusion pump. See the photo below.
Photo: The photomicrograph on the right shows charring and melting of failed connectors after a fire that occurred when pump modules were attached to a running unit.