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Human factors engineering

Designing a safe care environment

The promise of human factors engineering

Two males in hard hats looking at blueprintsHuman factors engineering is used to design and evaluate safer and more effective tools, machines, systems, tasks, jobs, and environments.  [REF]
Parush A., Campbell C., Hunter A., Calder L., Frank J., Worthington J., Abbott, C., Situational Awareness and Patient Safety. For more information email canmeds@royalcollege.ca. (This educational project was funded by the CMPA.)

Although it is unlikely that we can completely eliminate factors that contribute to patient harm, human factor engineering principles can reduce the likelihood and impact of such failures.

Design principles in healthcare settings

  1. Forcing functions: makes it impossible to do a task incorrectly.

    For example, the connectors to the oxygen and nitrous oxide gas containers can be designed to make it impossible to physically connect them to the wrong cylinder.

    Another example would be to design a connection for syringes of vincristine that would make it impossible for the drug to be given intrathecally.

  2. Constraints: make the right choices the easy choices and make it hard to do the wrong thing.

    For example, removing potassium chloride from patient wards; removing hypotonic and hypertonic electrolyte solutions from patient wards; storing look-a-like drugs in different areas or developing distinctly different packaging.

    Constraints do not make it impossible to do the wrong thing like a forcing function, but they do make it difficult and therefore allow for many opportunities for checks.

  3. Simplification: the reduction in the number of steps in processes or procedures.

    Because each step in a process of care may fail on occasion, processes with a greater number of steps are generally more prone to failure than those with fewer steps.

    When a process is extremely complex and inefficient, health providers are more likely to develop routine workarounds to make it simpler, which may sometimes put patients at risk.

  4. Standardization: promotes consistency and eliminates confusion.

    For example, the use of a standard order form or a standard operating room setup.

  5. Use of redundancies: such as double checking narcotic dosing prior to administering the drug to a patient.

    Computers can facilitate the double check by alerting the provider to the wrong dose of medication or a contraindicated medication.

  6. Avoiding reliance on memory: most people can hold only a limited number of pieces of information in their memory at any one time.

    Checklists such as the surgical safety checklist, checklists for central line insertion and for handovers help to reduce reliance on memory and are increasingly being used for complex or high-risk procedures.

  7. Creation and adherence to patient safety habits: for example, patients can be encouraged to bring their medications to every office or hospital visit so that it becomes a consistent pattern of behaviour.

  8. Use technology wisely: while information technology has transformed the way we work and live and is an enabler of improvements to patient safety, it is not a guarantee.

Case: Failed alerts in an electronic health record (EHR)
Male physician working on computer


A 37-year-old construction worker is employed in northern Canada. He develops severe radiating back pain following heavy lifting. He is seen by a physician locum in a walk-in clinic.

The physician enters the history and physical examination, including weakness of the dorsiflexion of the right foot, into the new electronic health record at the clinic. He makes a diagnosis of an acute herniated lumbar disc, orders a CT scan, prescribes analgesics, and discharges the patient with arrangements for follow up.

The CT scan is done two weeks later and read the same day. The radiologist identifies a destructive process in the spine. The report is emailed to the physician, however, it is never received.

Nine days later the patient's condition becomes much worse, he is admitted to hospital, and spinal tuberculosis is diagnosed.

Background continued

The EHR had a diagnostic decision support tool; however, the audit system indicates the physician spent only 1.5 seconds reviewing the suggested possible diagnoses. He was not familiar with its use and considered the list of possible diagnoses, which included spinal tuberculosis, too time consuming to read.

The EHR had a tracking system for investigative reports which was not being used by the clinic as they had not been trained on how to work with it.

The EHR also had a system for patient follow-up which the staff had not yet learned to use. The patient safety alerts had been turned off to enable the system to run faster.

Think about it

  • Why didn't the EHR prevent the delay in the diagnosis of the patient's spinal tuberculosis?

Lessons learned

  • The physician and staff did not have adequate training on the EHR and were not aware of all the patient safety advantages it could provide.
  • The tracking system for investigations and patient follow-up was not being used.
  • The decision support tool was considered too time consuming to use and was ignored.

Technology will not achieve the promise it holds for patient safety if:
  • providers become desensitized to the alerts and turn them down or off
  • providers are not trained adequately to fully use the systems
  • the technology significantly interferes with normal work flow, for example, if computer terminals are at the end of a hall instead of in each examining room
  • the systems are poorly designed
    (In one example, a pathology department developed a bar coding system to ensure each pathology slide was correctly linked to the right patient specimen. To avoid error, the technologists were instructed to print out each bar code one at a time when fixing the individual slides. However, the bar coding label printer was so slow that the technologists printed out all the bar codes for their workstation for the day, circumventing the safety precaution.)
  • everyone becomes over-confident in the system and does not know how to function if the system is down.

Technology is an enabler and holds great promise for safe care. To achieve this promise, the technology should be designed for, and evaluated by, the healthcare provider who will be using it.