Binseng Wang, ScD, CCE, FAIMBE, FACCE

Binseng Wang, ScD, CCE, FAIMBE, FACCE

In December of 2011, the Centers for Medicare and Medicaid Services (CMS) issued a clarification of hospital equipment maintenance requirements1 contained in the State Operations Manual Provider Certification. This clarification stated that critical equipment must be maintained at the frequency recommended by the manufacturer, whereas the frequency of noncritical equipment can be modified using evidence-based assessments.

CMS did not provide a definition for critical equipment but stated “[e]quipment that is critical to patient health and safety is not a candidate for an alternative, less frequent maintenance activity schedule. Such equipment must be maintained at least as often as the manufacturer recommends. At a minimum such critical equipment includes, but is not limited to, life-support devices, key resuscitation devices, critical monitoring devices, equipment used for radiologic imaging, and other devices whose failure may result in serious injury or death of patients or staff.” While useful, this statement does not preclude a precise definition that hospitals can use to for maintenance management.

Most people would probably associate the term “critical” with “indispensable” or “essential.” However, the fact that CMS mentioned safety suggests that potential failure consequences should also be considered. Therefore, I would propose the following definition: Critical equipment is essential for patient care under normal operating conditions and whose failure could cause imminent serious injury or death to patients or users. Here, the term “essential” is preferred because it helps clinicians to relate to “essential medicines.”2 “Under normal conditions” excludes natural and man-made emergencies in which most equipment could become critical due to challenges in obtaining backups and prompt repairs. “Cause” is used to stress the causal linkage between equipment failure and patient/user impact. Examples of critical equipment as defined above include but are not limited to: (1) life-support equipment3 such as ventilators, (2) resuscitation equipment such as defibrillators, (3) mission-critical equipment such as a CT scanner, (4) dialysis systems, and (5) sterilizers. On the other hand, some of the CMS examples would not fit into this definition. For example, the manual resuscitation device popularly known as an “Ambu bag” is not a piece of equipment but a single-use, disposable device. The intensive care unit patient monitor is connected to the central monitoring system, so failures are unlikely to cause harm. Likewise, radiological equipment has proven to be safe even if it fails catastrophically and backup is typically available.

Some may question the inclusion of mission-critical equipment, as it is traditionally considered “diagnostic” equipment and, thus, apparently less likely to cause harm. However, the unavailability of this kind of equipment can delay physicians’ decisions and interventions to the point of harming not just one but several patients.

Even if the definition proposed above were widely accepted, it is difficult, if not impossible, to create a single, universal list of critical equipment for the entire nation. This is because hospitals have different specialties, patient acuity, and geographical limitations. Some may have multiple CT scanners, whereas others may have only one of a kind. For this reason, the list of critical equipment should be decided by the hospital through a consensual process led by its safety authority with the participation of clinical engineering leaders.

Even more challenging is finding the right answer to the second question in the title because maintenance alone does not ensure reliability and safety. All man-made machines will eventually fail for one reason or another, and not all failures can be prevented. Furthermore, maintenance need does not depend on whether a piece of equipment is considered critical, but on how the equipment is designed and built. Some equipment has moving and/or wearable parts that need to be lubricated and/or replaced periodically (known as preventive maintenance or PM), whereas others are based on solid-state electronics that fail in a random manner. Some of the unpreventable failures are unknown to users (“hidden”) or could be in the process of occurring (“potential”); these failures can be detected by technicians using specialized test equipment in a process called safety and performance inspection, or SPI.

From the proposed definition, critical equipment presents high severity of harm in case of failure, so its maintenance should be composed of PMs, if there are replaceable parts, and SPIs, if there are hidden and potential failures.

These actions will reduce the probability of failure and, thus, risks of harm to patients and staff.4 As data from TJC Sentinel Events5 and reports published previously6 have shown, most of the injuries and death are actually caused by use error (or human factors). It would be wiser to invest the limited clinical engineering resources in working more closely and helping to better educate the users and the manufacturers in using and producing better health care equipment.

Binseng Wang, ScD, CCE, FAIMBE, FACCE, is vice president, quality and regulatory compliance, Aramark Healthcare Technologies, Charlotte, NC. For more information, contact .

References and Notations
  1. The full text is available at:
  2. Essential medicines are those that satisfy the priority health care needs of the population. They are selected with due regard to public health relevance, evidence on efficacy and safety, and comparative cost-effectiveness. Essential medicines are intended to be available within the context of functioning health systems at all times in adequate amounts, in the appropriate dosage forms, with assured quality and adequate information, and at a price the individual and the community can afford. Extracted from, consulted on 5/15/2012.
  3. The Joint Commission defines life support equipment as: “Any device used for the purpose of sustaining life and whose failure to perform its primary function, when used according to manufacturer’s instructions and clinical protocol, will lead to patient death in the absence of immediate intervention (for example, ventilators, anesthesia machines, heart-lung bypass machines, defibrillators).
  4. Wang B, Poplin B. Are You Managing Risk or Severity? 24×7. August 2011.
  5. Available at:
  6. Wang B, Fedele J, Pridgen B, et al. Evidence-based maintenance: Part III, Enhancing patient safety using failure code analysis, J Clin Eng. 2011;36:72-84.

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