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Administering anesthesia in a complex environment of high technology and new surgical innovations is a risky process where any human or equipment failures can result in serious consequences for the patient. An ergonomic and simplified design of the anesthesia workplace should be regarded as a matter of continual evolvement.


Ergonomics, or human factors engineering, is the scientific study of interactions between humans and other components of a system. The purpose of ergonomics is to promote operational efficiency and to decrease human error. Within anesthesiology, ergonomics promotes patient safety by reducing stress and strain on the user.

The American National Standards Institute and the Association for the Advancement of Medical Instrumentation promote attention to ergonomics during the design of medical instrumentation. To apply ergonomics in the anesthesia work environment, it is useful to have a model of the anesthesia provider at work. The model has three elements (anesthesiologist, equipment, and the patient) and two interfaces (ergonomics and machine design). The areas studied in ergonomics include equipment design, workplace layout, environmental conditions such as lighting, and the related questions of skill acquisition, productivity, and safety. The ergonomics of controls and displays has special relevance as anesthetic technology becomes more complex.


Innovations and Discoveries

Historically, there have been four main technological innovations in the area of anesthesia equipment design (Table 20-1):

  1. In the early 1900s, the equipment consisted of small hand-held devices, mainly a folded towel and bottle containing anesthetic agents. Later, the cloth was supported by a wire mask and then to a more complex inhaler combining the mask and bottle as one device.

  2. In the 1920s, inhaler technology was integrated into a floor-mounted or portable apparatus, where multiple anesthetic agents could be compressed in cylinders with reducing valves and controlled simultaneously.

  3. In the 1930s, the anesthesia machine was enhanced with further advancements such as the Waters’ soda lime canister, which was added in a table format.

  4. From 1950 to 2000, major new components and safety features were added. These parts included work surfaces and drawers, calibrated vaporizers, common gas outlet, and mechanical ventilators. Integrated monitors and central display data recording was developed in the 1990s. Due to new clinical demands, a complete workstation was developed. By integrating devices for patient monitoring and ventilation, the new design allowed for fresh gas flow, independent ventilation, compensation for circuit leak and circuit compliance, intensive care unit (ICU) modes of ventilation and synchronization, electronic vaporization, and automatic preuse checks.

TABLE 20-1A Chronology of Major Safety Features for the Anesthesia Machine

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