Human Factors Enineering (HFE) include all factors that can impact people and their behavior. In a work context, human factors are the environmental, operational, technological, mission/organizational-related, economic, political, social characteristics which influence behavior at work. Every day tens of thousands of patients are treated safely by dedicated healthcare professionals who are motivated to provide high quality clinical care and a safe environment. For the majority of patients, the treatment received improves their symptoms and becomes a positive experience to the patient. However, we still have an unacceptable number of patients that are still harmed as a result of their treatment or admission within our hospital organization.[1]


Human Factors began during World War II and came out of the disciplines of industrial engineering and experimental psychology. Many discipline practitioners served in World War II and witnessed very poor system designs that were often unsafe and difficult to operate. Prior to World War II, the focus was “designing the human to fit the machine” (i.e., trial and error), instead of designing machines to fit the human. Many of the human factors and ergonomic advances within this field originated out of military necessity and lessons learned. With the start of World War I, the first conflict to employ the newly invented airplane in combat, the need arose for methods to rapidly select and train qualified pilots to man these vehicles. Aeromedical research continued to see advances in laboratories built at Brooks Air Force Base, Texas and Wright Field, Ohio. This prompted the development of aviation psychology and the beginning of aeromedical research.  Although some progress was made during the 1950’s, 60’s and 70’s to determine man’s physical and physiological ability in space flight the U.S. Air Force began human factor testing of g-forces, spacesuits, balloon flights and oxygen re-use equipment on animals (i.e. chimpanzees) and human subjects in order to recognize the need for greater attention to human space flight design. The integration of human factors and devices mixed together in the early 1980’s was utilized heavily as a method to address a rapid increase in work-related mishaps, loss of manpower, loss of personnel and high training costs, and to reduce associated total life cycle costs (i.e. annual service contracts). In the United States, the profession has grown from behavioral sciences, like experimental psychology, and certain engineering disciplines. Among European nations, the profession has become rooted in the physical sciences, like human physiology. Today, individuals from a number of disciplines ranging from psychology, engineering and physiology, focus their unique skills and abilities to the study of how people interact with devices and as technology advances and grows so will consistent theme of the ever expanding field of human factors and ergonomics towards advancement in patient safety within the clinical environment.[2]

Work Elements

These fundamental elements are a distinct academic approach surrounding the entire set of systematic, technological, and management related efforts needed to consider, to develop, to validate, to deploy, and to support an integrated and life cycle balanced set of human factors that concentrate on workers occupational health and patient safety.

Typically, work elements include Physical, Operational, Technological, Organizational, Economic, Political, and Social that can create an unrealistic, unconventional, and unsocial intimidating work environment if left unmanaged. It is very important for leadership to recognize that employees who are unable to perform their tasks are incapable to do so because of the human factors being displayed. For those supervisors, managers, and leaders who correct these environmental behaviors foster healthy workplace environment, improved communication and higher worker productivity. In fact, human beings are happiest and work hardest when employers have committed their employees to receive adequate and proper training (sometimes re-training), encourage worker breaks and keeping to sensible working hours, motivating employees to get involved with hobbies outside of work to build morale, supervisors and managers fostering healthy work habits as well as workplace camaraderie. Remember that a “happy employee can also be a happy life for you!” In addition, an outstanding rule of thumb for managers to practice is to always reward in public and punish in private next we’ll talk about the different types of work place model elements.

The following examples elements are below. Keep in mind that many of these elements can be prevented and/or should be routinely monitored by management oversight to quickly resolve these discrepancies with the employee’s health, happiness, safety, and security in mind resulting in a highly effective work force to help healthcare organizations save money by eliminating hospital mishaps and patient errors.

Physical—inadequate office space, room locations, and/or weak building designs, poor air quality (i.e. high humidity, high/low temperatures), poor quality of light, unacceptable noise levels, bad water quality or contamination, poor infrastructures (i.e. inadequate ventilation that leads to risk of transmission of airborne pathogens such as Aspergillus), unorganized patient workflow environment.

Operational—failure to provide user training/re-training, lack of documented user training, no designated team leader, discouraged teamwork, refusal on work demand (i.e. lack of job characteristics, lack of manpower, lack of resources and supplies), other risk factors (i.e. insufficient emergency preparedness plan and procedures).

Technological—outdated medical devices, insufficient testing of medical devices, uncalibrated testing equipment, functioning IT-related equipment and networks (i.e. internet, computers, printers, administrative rights).

Organizational—lack of organizational structure and policies (i.e. no smoking, general safety, ethics) no organizational chart (i.e. chain of command), unsound leadership (i.e. failure to get to know your people, families, facility, and other resources), and fostering an unhealthy civilized workplace.

Economic—working-age people with disabilities, severe budget cuts, low patient-community demographics, high turnaround rate of worker injuries and illnesses, employee layoffs/terminations, repeated infrastructure design changes, high associated costs with litigation cases, failure to control employee fraud, waste, and abuse.

Political—unsuccessful healthcare reforms, broken down government standards, monetary decisions being made by the politicians, rising healthcare medical malpractice costs.

Social—absence of positive social communication, small quantities effectively utilizing conflict resolution techniques, lost social-reinforcement theory, workers under the influence of alcohol or drugs, longer experienced wait times, acts of violence and assaults.

Psychological—depression, irritability, stress (i.e. unable to find child care arrangements, sick on the job, overweight workers, , job burnout, sleep deprivation leads to decreased worker satisfaction and poorer performance, tired, mood and anxiety disorders. For statistics see fact sheet.

Benefits of applying human factors in healthcare

Awareness of human factors such as those above can help you to: understand why healthcare staff make errors and in particular, which ‘devices, systems, factors’ threaten patient safety improve the safety culture of teams and organizations enhance teamwork and improve communication between healthcare staff improve the design of healthcare systems and equipment at the earliest phases of design. OEM designs the device with the user in mind from the beginning. identify ‘what went wrong’ and predict ‘what could go wrong’ appreciate how certain tools mentioned in this guide can help to lessen the likelihood of patient harm.

The Swiss Cheese Model of Medical Errors

The Swiss cheese model is frequently referred to and widely accepted by patient safety professionals who demonstrate great value in it.  The distinction made by British psychologist James T. Reason of the University of Manchester in 1990 between latent conditions and active errors is very important. In health care, active errors are committed by those clinical professionals (e.g., nurses, physicians, medical technicians) who are in the middle of the action, responding to patient needs at the sharp end.[3]

Defenses, barriers, and safeguards

Defenses, barriers, and safeguards are the cheese anatomy and occupy a key position in the system approach. High technology systems have many defensive layers: some are engineered (alarms, physical barriers, automatic shutdowns, etc), others rely on people (surgeons, anesthetists, nurses, technicians, etc), and yet others depend on procedures and administrative controls. Their function is to protect staff, patients, and medical devices from local hazards. Mostly they do this very effectively, but there are always weaknesses. In an ideal world each defensive layer would be whole and without holes in the cheese (weaknesses). In reality, however, they are more like slices of Swiss cheese, having many holes—though unlike in the cheese, these holes are continually opening, shutting, and shifting their location. The presence of holes in any one “slice” does not normally cause a bad result. Usually, this can happen only when the holes in many layers momentarily line up to permit opportunities for accidents—bringing hazards into contact with patients.

Active Failures

The holes in the defenses (cheese) arise for two reasons: active failures and latent conditions. Nearly all adverse events involve a combination of these two sets of factors. Active failures are the unsafe acts committed by people who are in direct contact with the patient or system. They take a variety of forms: slips, lapses, fumbles, mistakes, and procedural violations. Active failures have a direct and usually short-lived impact on the integrity of the defenses. At Chernobyl, for example, the operators wrongly violated plant procedures and switched off successive safety systems, thus creating the immediate trigger for the catastrophic explosion in the core. Followers of the person approach often look no further for the causes of an adverse event once they have identified these proximal unsafe acts. But, as discussed below, virtually all such acts have a causal history that extends back in time and up through the levels of the system.

Latent Conditions

Latent conditions are the inevitable “resident pathogens” within the system. They arise from decisions made by designers, builders, procedure writers, and top level management. Such decisions may be mistaken, but they need not be. All such strategic decisions have the potential for introducing pathogens into the system. Latent conditions have two kinds of adverse effect: they can translate into error provoking conditions within the local workplace (for example, time pressure, understaffing, inadequate equipment, fatigue, and inexperience) and they can create long-lasting holes or weaknesses in the defenses (untrustworthy alarms and indicators, unworkable procedures, design and construction deficiencies, etc). Latent conditions—as the term suggests—may lie dormant within the system for many years before they combine with active failures and local triggers to create an accident opportunity. Unlike active failures, whose specific forms are often hard to foresee, latent conditions can be identified and remedied before an adverse event occurs. Understanding this leads to proactive rather than reactive risk management.

Remove the Blame Culture

The way we have traditionally managed failures and mistakes in health care has been called the person approach—we single out the individuals directly involved in the patient care at the time of the incident and hold them accountable. This act of “blaming” in health care has been a common way for resolving health-care problems. We refer to this as the “blame culture”. Since 2000, there has been a dramatic increase in the number of references to the “blame culture” in the health literature. This is possibly due to the realization that system improvements cannot be made while we focus on blaming individuals.

It is human nature to want to blame someone and far more “satisfying” for everyone involved in investigating an incident if there is someone to blame. Social psychologists have studied how people make decisions about what caused a particular event, explaining it as attribution theory. The premise of this theory is that people naturally want to make sense of the world, so when unexpected events happen, we automatically start figuring out what caused it. Pivotal to our need to blame is the belief that punitive action sends a strong message to others that errors are unacceptable and that those who make them will be punished. The problem with this assumption is that it is predicated on a belief that the offender somehow chose to make the error rather than adopt the correct procedure: that the person intended to do the wrong thing. Because individuals are trained and/or have professional/organizational status, we think that they “should have known better”—Wrong assumption!

User errors have become less prevalent with the invention of newer, more complex technological devices. Human actions are almost always constrained and governed by factors beyond an individual’s immediate control or outside limitations. Today some intelligent managers have started to realize that a blame culture will not bring safety issues to the surface. While other healthcare organizations are beginning to recognize this we are yet to move away from the person approach—in which finger pointing or cover-ups are common—to an open culture where processes are in place to identify failures or breaks in the “defenses”. Hospitals that place a premium on safety routinely examine all aspects of the system in the event of an accident, including equipment design, procedures, training, and written policies have produced a highly effective continuum of care for staff, patients, and families.[4]

Device Users Limitations, User Environments and Device-User Interface

When users interact with a device, they perceive any information provided by the device, then interpret and process the information and make decisions. After that the user may interact with the device to change some aspect of it. The device then receives the user input, responds to the input, and provides feedback to the user. The user might then perceive the new information and might initiate another cycle of interaction. The user interface includes all components of a device with which the user interacts, such as controls and displays (i.e., those parts of the device that users look, listen, smell, taste, and touch—the human body’s 5-sense organs). The user interface also includes the device labeling, which includes package labels, any instructions for use in user manuals, package inserts, instructions on the device itself, and any accompanying informational materials. To gain an understanding of the potential HFE/UE analyses that should be conducted for a particular device, you should consider:

1. Device users:

1.1. Identification of the end-users of the device (e.g., patient, family member, physician, nurse, professional caregiver)

1.2. The level of training users will have and/or receive

1.3. User characteristics (e.g., functional capabilities, attitudes and behaviors) that could impact the safe and effective use of the device

1.4. Ways in which users might use the device that could cause harm

2. Device use environment: 1.1. Hospital, surgical suite, home, emergency use, public use, etc.

1.2. Special environments (e.g., emergency transport, mass casualty event, sterile isolation, hospital intensive care unit)

1.3. Interoperability with other devices 3. Device user interface :

1.1. E.g., functions, capabilities, features, maintenance requirements

1.2. Indicated uses These considerations, discussed in the following sections, will help you identify specific aspects of device use that are associated with potential use-related hazards that should be investigated through Human Factors Engineering analysis and testing.[5]

Device Users

The device users are the equipment operators. Each person varies in ability to operate various medical devices. The intended user should be able to use the medical devices safely and effectively and without unintentionally making errors that could compromise patient safety. With proper application of Human Factors Engineering, the design of a device can be modified to be either less dependent on the abilities of the user or more accommodating of the users physical disabilities. For example, people with diabetes often have some degree of retinopathy (a degenerative disease of the retina), which causes impaired eyesight. These users have difficulty reading displays, such as on blood glucose testing meters, especially when the text is small or the visual contrast is low. Depending on the specific device and its application, device users may be limited to professional caregivers, such as physicians, nurses, nurse practitioners, physical and occupational therapists, social workers, and home care aides. Other users may be non-professionals, including patients who operate devices on themselves to provide self-care and family members or friends who serve as lay caregivers to people receiving care in their home, including parents who use or supervise the use of devices for their children. Device users may also include the professionals who install and set up the devices and those who maintain, repair, clean and reprocess them. The ability of a user to operate a medical device depends on his or her personal characteristics, expectations, and/or limitations, including:

Physical size, strength, and stamina,

Physical dexterity, flexibility, and coordination, Sensory abilities (i.e., vision, hearing, tactile sensitivity),

Cognitive abilities, including memory,

Medical condition for which the device is being used,

Comorbidities (i.e., multiple conditions or diseases),

Literacy and language skills, experience, training General health status,

Mental and emotional state,

Level of education and health literacy relative to the medical condition involved,

General knowledge and understanding of similar types of devices, and/or policies Knowledge of and experience with the particular device,

Ability to learn and adapt to a new device, and Willingness and motivation to use a new device. You should evaluate and understand essential characteristics and/or limitations of all intended users.[6]

Device Environment

The device environment is where the device is going to be used such as operating rooms, pediatrics, wards, etc… Environments in which medical devices are used can present a range of difficulties for the operator and device itself. Medical devices may be used under limited operating conditions involving space, lighting, noise levels, temperature, and humidity and so on. Additional examples of environmental hazards in the clinical setting can include the following:

Rooms can be physically crowded or cluttered, making it difficult for people or the medical devices to maneuver in the space.

The lighting level can be low, making it hard for the operator to see device displays or controls.

TThe noise level can be high, making it hard for the operator to hear the device operation feedback and status so he or she can avoid errors for audible alerts and patient safety alarms.

The room can be busy with other people and activities, providing distractions that can confuse the device operator. Non-clinical environments can present additional challenges. For example: Carpeting or stairs might make it hard to move medical devices around the space.

The environment might not be clean. The utility service might not be reliable. In addition, the electrical outlets might not be grounded or easily accessible, and the water might not be clean.

The temperature might be very high, which could cause devices to overheat (and make users’ hands sweaty), or the temperature might be very low, which could make devices inoperable (and make users’ fingers stiff and decrease sensitivity).

The humidity might be very high, which could cause condensation to form, or very low, which could produce static electricity. Other individuals and activities in the vicinity may cause distractions.

Other individuals and activities in the vicinity may cause distractions. Unauthorized users, such as children, might be present and could hurt themselves (e.g., playing with a syringe), accidentally damage the device (e.g., chewing on or misconnecting the tubing), or unintentionally change device settings (which might not be noticed by the operator before using the device the next time). Pets or vermin could contaminate and/or can damage devices in the home. Electromagnetic interference from other equipment (e.g., cell phones and computer accessories) could affect medical device performance. Use environments can also limit the effectiveness of visual and auditory displays (lighted indicators, auditory alarms and other signals) if they are not designed appropriately. For example, in noisy environments, the user might not be able to notice a device’s critical alarms if they are not sufficiently loud or distinctive. When multiple alarms occur for different devices or on the same device, or if alarms sound too often, i.e., “nuisance” alarms, the user could fail to notice them or be unable to make important distinctions among them. Similarly, motion and vibration can affect the devices internal components and degree to which people are unable to perform fine physical tasks such as typing on a keyboard or reading displayed alarms information.[7]

Device User Interfaces

The device-user interface is the device itself. The user interface includes all components of a device with which users interact while using the device, preparing it for use (e.g., unpacking, set up, calibration), or performing maintenance (e.g., cleaning, replacing a battery, repairing). A device-user interface includes what the user will touch, see, hear, and/or feel:

The hardware components that control device operation such as switches, buttons, and knobs, Device elements that provide information to the user such as indicator lights, displays, auditory and visual alarms,

The design of menu-driven interface systems, The logic that directs how the system responds to user actions including how, when, and in what form information (feedback) is provided to the user, The size and configuration of the device (particularly for hand-held devices), and Device labeling, packaging, training materials, operating instructions, and other reference materials.[8] Bottom line is always design medical devices with the user in mind as well as keep it simple from an operators point of view not from an engineers.


  1. Molly Follette Story, PhD. FDA /CDRH / ODE. Human Factors Engineering of Combination Products and the FDA.
  2. USAF. HUMAN FACTORS IN SPACE FLIGHT 1950 thru 1960--Story v2c8. youtube
  3. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000
  4. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000
  5. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000
  6. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000
  7. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000
  8. FDA. " Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management." July 18, 2000



Integrating Human Factors Engineering into Medical Devices

Integrating Human Factors Engineering into Medical Devices

Integrating Human Factors Engineering into Medical Devices