The complexities of anesthesia present unique challenges and risks that require comprehensive strategies to ensure patient safety. In a multi-center study carried out in 2006, the risk of perianesthetic mortality was estimated to be 0.17% in dogs, 0.24% in cats, and 1% in horses [1], [2]. In a retrospective mortality study in small animals, anesthetic death was found to occur most frequently in the 24 hours post-anesthesia (45%), followed by during the maintenance phase (35%), then induction (11%), and during premedication (9%) [3]. To achieve anesthesia safety, careful evaluation of the patients’ physical status remains paramount; however, thoughtful consideration must be given to other related factors such as equipment availability, trained personnel, standard of care, support resources, and culture of safety and teamwork within individual facilities.
The types of anesthesia machines and monitoring equipment remain diverse in veterinary medicine, although no overarching machine standards exists currently to govern the precision and accuracy of the variety of equipment. Due to the wide variety of species encountered in veterinary medicine, a single machine that is suitable for all species may not exist. Several monitoring equipment have been validated by independent researchers in a species-specific context. No matter the equipment chosen, it is prudent to understand how your specific equipment functions and ensure regular scheduled maintenance. Prior to each case, a machine check-out is recommended to ensure functionality of your equipment. Any malfunction in the machines should be documented and troubleshooted before returning to general circulation. There are readily available anesthesia checklists; one such example is published by the Association of Veterinary Anaesthetists (pdf).
Investment in adequate personnel training for basic anesthetic patient care and equipment knowledge is paramount. At minimum, an anesthetist must be familiar with the essential functions of the anesthesia machines, their routine maintenance, basic patient physiologic monitoring, and the “normals” vs. “abnormals” of patient parameters. A successful anesthesia team consists of an attentive and trained anesthetist who openly communicates their observations and concerns with the attending veterinarian early and often, and a knowledgeable veterinarian who can confidently guide the anesthetist through troubleshooting anesthetic complications.
There are standard of care documents published by board-certified anesthesiologists to enhance anesthesia monitoring in veterinary medicine [4], [5], [6]. These standards must be upheld by all practicing anesthetists whenever possible as they provide guidelines that aim to enhance anesthetic patient safety. Personnel involved in caring for patients within the peri-anesthetic period should be familiar with these guidelines, and regular refresher should be made available to all clinical staff within the hospital. It is important to understand that any monitor equipment serves to alert the anesthetist the presence of a potential problem; however, hyper-fixation on the monitor only could lead to potential neglect of the actual live patient that is attached to this machine. When assessing a patient under anesthesia, any parameters outputted by a monitor must be corroborated with parameters obtained by physical exam. For instance, if the heart rate sourced from ECG is unusually high or low, a pulse or heart rate should be manually counted to confirm ECG-sourced rate. Allowing the monitor to alert you to any potential problems early and frequently will help you detect any true patient problems in a timely manner.
Consider the support network around your hospital, including referral facilities or anesthesiologist consultants who may be able to provide additional support. These may come in the form of actual case transfer for higher levels of care, expert consultation, in-house case management, and delivery of continuing education. A frequently underutilized resource is academic anesthesiologists who will often happily answer questions from the referral community. To facilitate a productive discussion, gather all relevant case material before you call the university and call for consultation prior to the day of the scheduled anesthetic.
Lastly, a culture of safety and teamwork must be fostered within the hospital. Anesthetic complications are not completely avoidable, and when these complications do occur, a team that is built on the foundation consisting of a culture of safety and open communication will likely demonstrate resiliency and growth from these experiences. Accurate documentation of the anesthetic event will facilitate a more factual and focused discussion aiming to address what was known, what happened, and what could be improved next time. Analytical tools such as the Fishbone Diagram [7], [8] may assist in a more systematic evaluation of all factors that may have contributed to the negative outcome, rather than hyper-focusing on a single error.
All anesthetic events carry inherent risks. While some risks can be mitigated, it is not possible to avoid all risks. The cornerstone of anesthesia safety is preparation of the equipment, the patient, and the personnel knowledge. Through proper preparation, major peri-anesthetic morbidities and mortality can be avoided in most instances.