In the present study, the overall incidence of perianesthetic death was 8.8/10,000 anesthetics (95% CI, 6.1–11.6), whereas anesthesia-related death was not detected. Additionally, the incidence of anesthesia-contributory death was 2.1/10,000 anesthetics (95% CI, 0.69–3.6), and it was associated with hypovolemia, cardiac infarction, arrhythmia, and respiratory failure and was more common in elective surgery.
Previous studies have reported perianesthetic mortality using different definitions. Kawashima et al. used the definition of mortality occurring in the operating room and within seven postoperative days with accompanying critical events during surgery, whereas Lagasse et al. and Pollard et al. used the definition of death occurring within 48 h of anesthesia induction [2, 3, 7]. Our study used the latter definition, and the incidence of perianesthetic death (8.8/10,000) was similar to that reported in a recent study (7.5/10,000) . Furthermore, as expected, age, emergency surgery, and high ASA-PS were associated with perianesthetic death, and these findings are consistent with the findings of previous studies [3, 8, 10, 11].
Fortunately, there was no anesthesia-related death during the 10-year study period. This might be because our sample size was limited and there were no perianesthetic deaths associated with failed ventilation, aspiration of gastric contents, and accidental bolus of narcotics, which can lead to anesthesia-related death and anesthesia-related cardiac arrest [3,4,5,6].
In the present study, 10 patients experienced anesthesia-contributory death, with an incidence of 2.1/10,000 anesthetics, and this incidence is higher than that reported in a study from the USA (0.22/10,000) . This difference might be associated with differences in the study populations, including a smaller denominator, and the definitions of anesthesia-related death and anesthesia-contributory death. In addition, there was no anesthesia-related death in the present study, resulting in an increase in the incidence of anesthesia-contributory death. Furthermore, the rate of emergency surgery was higher among patients who experienced nonanesthesia-related death than among those who experienced anesthesia-contributory death. This might be because patient status, such as preoperative comorbidity, has greater effects on death when compared with anesthesia.
Among the 10 patients who experienced anesthesia-contributory death, 4 pathophysiological processes were identified. Hypovolemia is one of the most common complications during anesthesia, and almost all cases are managed well. Hypovolemia caused by rapid massive hemorrhage and large leakage into the tissues can lead to serious consequences, although this is rare. Perioperative acute myocardial infarction rarely occurs in patients undergoing noncardiac surgery, but it has been shown to be strongly associated with in-hospital mortality . One patient was suspected of ST-elevation myocardial infarction (case 7 in Table 3), and this patient had a history of angina pectoris. Another patient presented with acute myocardial infarction postoperatively (case 8 in Table 3), and this patient underwent aortic surgery owing to aortic dissection. Acute myocardial infarction might be caused by aortic dissection; however, this case was included in the anesthesia-contributory death group because we were unable to exclude inadequate oxygen delivery following perioperative low output syndrome. Arrhythmia caused by hyperkalemia after transfusion might be preventable with frequent blood analysis. The etiology of postoperative respiratory failure is unknown. However, it might be caused by preoperative multiple comorbidities, including anemia, heart failure, and kidney injury.
The limitations of this study include its representation of perianesthetic death from a single institution. Our institution is a 992-bed tertiary hospital and includes a trauma center, but there are no organ transplantation surgeries, except for kidney transplantations. The rate of perianesthetic death can vary depending on the institution and study population. Additionally, the data were evaluated retrospectively, and thus, we experienced missing data and analyzed limited data. Moreover, death and pathophysiological processes were classified independently by two researchers, and they consulted with another researcher at the time of disagreement. The decisions might be different for other anesthesiologists.