Life Support Equipment An Overview

Safety Concerns
The single most significant difference in supporting anesthesia technology, as distinguished from any other clinical engineering function, is that there is a susceptible patient connected to life-support equipment, and they are given medications that bring them relatively close to death. Anesthesiologists are keenly aware of this. As a whole, stress levels of people in operating rooms are exacerbated because the patient has undergone two forms of injury when on an OR table. They have suffered the initial illness or trauma that has brought them to the OR, and they must undergo the trauma of the surgical procedure itself. It can be difficult to believe that the patient often must experience additional trauma in order to get better.

Patient safety is a team effort. No single department bears the responsibility for overall patient safety. Everyone must evaluate their individual responsibilities and must look for ways to prevent and improve their environment, to prevent mishaps from occurring. One example of a relatively simple sounding task, but often complicated by various factors for the OR team, is patient positioning. A number of injuries have occurred because of positioning. Different departments must take into account their own prospective needs. Surgeons must have access to certain areas for sterile prep and the surgical site. Nurses must make sure that the items for which they are responsible are accessible and do not cause potential pressure points, while anesthesiologists are looking out for potential nerve injuries. Because the patient is unconscious, he is unable to tell them that the position is uncomfortable, and staying that way for six hours can hurt.

Anesthesia safety is frequently compared to flying an airplane. On airplanes, most of the problems (and, therefore, most hazards) are associated with take-off and landing. In anesthesia, this is equivalent to induction and emergence. Both have multiple systems working in unison to maintain function. On a commercial plane, fuel is delivered precisely to engines that are attached via structural members to a fuselage, with a crew using radiofrequency communication and a global positioning system to move the plane from one location to another. During anesthesia, oxygen is mixed carefully with an inhaled anesthetic agent and delivered through a breathing circuit driven by a ventilator, controlled by a physician who watches a display to monitor electrical and physical changes in a patient who cannot communicate. As long as things are going well, everything appears to be relatively simple.

Unfortunately, things do not always go as planned. A number of factors can contribute to undesired events during anesthesia, including noise, fatigue, and boredom (Weinger and Englund, 1990). Studies have shown that anesthesiologists can be idle 40%-70% of the time during a surgical procedure (Drui et al., 1973; Boquet et al., 1980), which could further affect their vigilance at their primary responsibility of monitoring the patient, procedure, and equipment. When something out of the ordinary occurs and takes anesthesiologists off their planned course, it can lead to moments of high activity, where many things must be accomplished in little time, potentially in a state of concern. These periods are often associated with high task density, where people average less time on individual tasks in contrast with the time spent during less busy periods (Herndon et al., 1991). In both aviation and anesthesia, there are lengthy, intensive training periods and highly educated and skilled personnel. Each field relies on a person who has a widely varying workload, to maintain order. It does not take much time for one or two additional missed warning signs to result with significant demands on the individual at the controls. For a pilot or an anesthesiologist, an uneventful day is a good day. No one likes unpleasant surprises on an airplane or in anesthesia.

Redundant systems help to prevent surprises. Studies in the aviation industry show that adverse outcomes frequently happen when a number of undetected smaller events occur, involving different factors (e.g., human error, equipment failure, and supply mishaps) cumulating in an undesired result (Billings and Reynard, 1984). There always should be additional resources for people to turn to for help. This can be difficult for some, because they may feel that asking for help shows a weakness and that they should be able to figure it out on their own, lest they be seen as less than fully capable. Patient care environments must try to foster a setting in which looking for help when an individual is not fully comfortable with a condition is a perfectly respectable option and not cause for punitive action. Solutions can be relatively simple but not visible when an individual is fixated on something else. Another viewpoint might be all that is needed. Physicians frequently have enough to worry about and might not always see the solution; this state of affairs can be more prevalent at teaching institutions. Clinical engineers can back physicians up by understanding the demands placed on them and on the clinical environment.

To minimize the possibility of equipment failures during use, the aviation industry implemented a preflight inspection. Similarly, those who are concerned with anesthesia safety developed the United States Food and Drug Administration (FDA) Anesthesia Apparatus Check-out Recommendations (FDA, 1993). A team of people of varied backgrounds and interests created the FDA procedure. When followed correctly, this comprehensive procedure can identify most any problem. Although it is a simple procedure, it does require the user to know proper technique. It can be simple to make a mistake (e.g., negative pressure leak test with the machine turned on) that results in false positives or negatives. Most anyone with a reasonable understanding of an anesthesia machine can perform the checkout. A technician or engineer with more in-depth knowledge of the components that are actually being tested can use it as a useful troubleshooting tool to easily identify system failures within the machine.

The aviation industry has used simulators for years. Their use is expanding medicine to put physicians in stressful situations without putting patients at risk. People need to be taught crisis management. One needs to conceptualize and understand how to work in a team when encountering stressful and challenging situations. The human mind does not function rationally when in a panic.

Safety at off-site locations is worth noting. A number of undesired events have prompted review of office-based anesthesia. The associated risk versus cost is an example of the many challenges faced in health care, particularly at large teaching hospitals. In an effort to stay price-competitive with the entire medical industry, procedures are being performed out of the operating room and in doctors’ offices. No one should ignore the fact that infrequent events with potentially catastrophic outcomes do happen. Key components can be as simple as proper and adequate supplies, additional personnel, and available telephones. Other components depend on the procedure and level of anesthesia performed. Even though some procedures appear to be relatively simple, the requirements for anesthesia can call for a machine to be present at all times. The emergent need for mechanical ventilation and use of volatile agents is quite possible. These machines might be underutilized, but they are subject to greater wear because they are moved more frequently than machines based in the operating room.

There are supply concerns, as well. Additional stock is not as readily available when users are not in the main supply area, which normally is the operating room. If items stored differently, individuals are out of their normal surrounding, and this contributes to disorientation and difficulty locating the items. Delays in supplies can have catastrophic results, as well. If the correct endotracheal tube is not readily available, minutes might as well be hours when there is a problem with an airway.