Chapter 41. Human Factors and Medical Devices (continued)
Events related to medical equipment can be divided into two categories, user-error and equipment failure.43 Health device inspection and preventive maintenance by biomedical or clinical engineering departments have high face validity as an important patient safety practice in reducing equipment failure.
There are many calls in the engineering literature to standardize equipment maintenance.44-46,46 Standardization of protocols is believed to help make the processes more efficient and reduce errors.47 However, it has been difficult to standardize equipment maintenance practices due to a lack of the appropriate units on which to base measurement.46 Some authorities have suggested outcomes based on engineering endpoints such as reliability and accuracy.48 Others have tried to validate a set of maintenance outcome units based on cost or quality metrics.44,45,49 Some engineers have suggested the incorporation of clinical endpoints into medical equipment assessment.48,50 Notwithstanding differing views as to measurement of endpoints, experts uniformly believe that standardization of engineering endpoints is vital to ensure adequately inspected and maintained equipment.46 No studies to date have developed a widely used standardized protocol for equipment maintenance for clinical engineering departments, largely because the lack of standardization of endpoints renders assessing the relative value of any particular maintenance protocol impossible.44-46,48,50 Nonetheless, equipment failure does result in a small fraction of clinical events and thus is an important safety intervention. Hopefully, future studies will help delineate the most effective practices for equipment maintenance processes.
Use of checklists is another practice that helps ensure equipment readiness, particularly for equipment that is needed in critical situations and/or where equipment failure may have dire consequences. For example, a nurse at the beginning of each shift may use a checklist to ensure the readiness of a hospital ward's resuscitation cart ("crash cart") should it be needed (e.g., the defibrillator is plugged-in and charged, the back-up suction pump works, medication is not past its expiration date). Similarly, a perfusion technologist can use a checklist to ensure cardiac bypass circuit and back-up equipment are ready before surgery. Published studies on the effectiveness of equipment checklists largely relate to the use of preoperative checklists to prevent anesthesia equipment failures since, to date, studies on the effectiveness of equipment checklists in medicine have been limited to this area.51-53,54 These studies are reviewed in Chapter 23.
Final Comment to Chapter 41
Human factors testing is yielding important data regarding safe and effective medical device and alarm designs that take into account the users' cognitive limitations. Machines can be designed and redesigned that enhance patient safety, rather than compromise it.
Currently, there are no widely accepted standards for equipment maintenance intervals and protocols. Maintenance endpoints that incorporate clinical events as one component of the endpoint have been suggested. Until a reliable and validated engineering endpoint metric is widely recognized it will remain difficult to investigate the most effective maintenance practices.
Other than the pioneering work in anesthesiology, HFE has been underutilized in medicine. Hopefully, in the near future, more attention will be focused on integrating human factors engineering within all aspects of medical training and practice, which will help create a culture of safety.
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