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The closed-circuit anesthesia machine has become the main-stay for providing oxygenation, ventilation, and administration of volatile anesthetics to patients to allow for otherwise intolerably painful procedures to be performed in modern-day medicine. Anesthesia machines and the providers utilizing them have become such an essential component of the operating room that they have evolved to incorporate various electronic monitoring equipment and complex ventilators to become what is known as the "anesthesia workstation." This activity reviews the anesthesia machine's important components and functionality, highlighting the importance of the interprofessional team's understanding of the anesthesia machine to prevent adverse outcomes. Objectives: Identify pitfalls of the anesthesia machine that could potentially result in patient harm. Review the safety mechanisms in place on the anesthesia machine. Explain the difference between high, intermediate, and low-pressure systems of the anesthesia machine. Describe in detail the issues of concern and clinical significance for a better understanding of the interprofessional team. Access free multiple choice questions on this topic.

The modern anesthesia machine is a complex operating room instrument that incorporates a ventilator to optimize the delivery of inhaled anesthetics. The anesthesia machine has gradually evolved from simply a means to anesthetize and oxygenate a patient to an anesthesia workstation incorporating increasingly complex ventilator modes, end-tidal CO2 monitors, end-tidal anesthetic concentrations, minimal alveolar concentration estimators, and a means of monitoring vital signs.[1] Despite all these innovations and new instruments added to the anesthesia machine, an understanding of the anesthesia machine is still a core component of the practice of anesthesiology.

The operating room can be a stressful environment requiring synchrony of motion between all members of the operating room staff: anesthesiologists, surgeons, nursing, and even operating room aides. At the center of the operating room is the patient, the surgeon performing a procedure, and an anesthesia provider often manipulating an anesthesia machine to ensure appropriate patient comfort, oxygenation, and ventilation. Anesthesia machines have become complex pieces of medical equipment incorporating a ventilator and various forms of monitoring devices to ensure patient safety requiring an anesthesia provider's vigilant attention to ensure proper functioning. Despite the advances made in anesthesia delivery, the anesthesia machine is still prone to human error inhibiting proper function. Teamwork and education about the anesthesia machine amongst all operating room personnel can help create awareness about its importance, areas of weakness and solutions to common problems to reduce morbidity and mortality in the operating room.  For example, a nurse noting an anesthesia provider having a difficult time mask ventilating a patient with a beard can squeeze the reservoir bag of an anesthesia machine while an anesthesia provider uses two hands to create a better mask seal to facilitate anesthesia machine function. Technology related to anesthesia machines has advanced extensively to make anesthesia safer to administer. Human error appears to be the dominant factor related to critical anesthesia incidents and negative outcomes related to the administration of anesthesia. In a cohort study of critical incidents related to the administration of anesthesia, only 4% of substantive negative outcomes were related to equipment failure. [Level 3] Greater education amongst healthcare providers about the functions/workings of the anesthesia machine and better interprofessional communication can allow for more rapid identification of errors and likely reduce the morbidity and mortality associated with anesthesia.[14]

Technology related to anesthesia machines has advanced extensively to make anesthesia safer to administer. Human error appears to be the dominant factor related to critical anesthesia incidents and negative outcomes related to the administration of anesthesia. In a cohort study of critical incidents related to the administration of anesthesia, only 4% of substantive negative outcomes were related to equipment failure. [Level 3] Greater education amongst healthcare providers about the functions/workings of the anesthesia machine and better interprofessional communication can allow for more rapid identification of errors and likely reduce the morbidity and mortality associated with anesthesia.[14] Operating room staff must be educated about the occupational hazards associated with improper use of anesthesia machines. Exposure of volatile anesthetics to rats has been associated with a range of medical complications, including nephrotoxicity from Compound A associated with sevoflurane and impairments in memory.[15][16] However, a meta-analysis of a plethora of randomized control studies involving the relationship between compromised renal function in a healthy patient failed to find any significant relationship.[17] [Level 1] Despite this, operating room staff, particularly female anesthesiologists, have been shown to have higher rates of spontaneous abortions and infertility compared to the general population.[7] Thus, volatile anesthetics from anesthesia machines must have a properly functioning gas scavenging apparatus and proper education on its use to reduce the risk of long-term exposure of volatile anesthetics to operating room staff.

Modern anesthesia machines have become more complex over the decades, incorporating an array of safety features, alarms, and displayed messages enhancing user-friendliness.  Despite these advances, the machine is still prone to user error and thus requires the attention and focus of all operating room personnel in anticipation of a dreaded scenario of failure to oxygenation/ventilate or anesthesia awareness. Although an understanding of the intricate workings of the anesthesia machine is not a requirement of all operating room staff, familiarity and awareness of components of the machine may help provide a safer anesthetic to the patient. Healthcare team awareness of the location of a bag-valve-mask or self-inflating bag to hand off to the anesthesia provider can provide a temporary means of oxygenation and ventilation until anesthesia machine issues are resolved if the machine fails.  Familiarity with the flaws of a low-pressure, circle-circuit anesthesia machine that is complex and prone to leaks may allow for greater confidence in nursing and allied health professionals to point out when a tube is disconnected so the anesthesia provider can quickly resolve issues to prevent unnecessary adverse outcomes.  With the emphasis on faster turn-over times between cases, it can be easy for operating room staff to forget that the anesthesia machine is the most important piece of equipment in the operating room. Failure of its proper function can lead to hypoxia and death or anoxic brain injury in a matter of minutes.  Although routine, anesthesia providers must have the time they need to check the machine and ensure its proper functioning before the arrival of a patient to the operating room so concerns and issues can be addressed safely and effectively.