[Annual study of anesthesia-related mortality and morbidity in the year 2001 in Japan: the outlines--report of Japanese Society of Anesthesiologists Committee on Operating Room Safety]

Abstract

We reported anesthesia-related mortality and morbidity in Japanese Society of Anesthesiologists Certified Training Hospitals (JSACTH) in the year 2001, as a part of the second series of annual studies in the identical questionnaires form started in 1999. JSA Committee on Operating Room Safety sent confidential questionnaires to 813 JSACTH and received effective answers from 87.9% of the hospitals. A total number of 1,284,957 anesthetics were documented. The respondents were asked to report all cases of cardiac arrests and other critical incidents (serious hypotension, serious hypoxemia and others) during anesthesia and surgery, and their outcomes (death in operating room, death within 7 days, transfer to vegetative state and rescue without sequelae) as well as one principal cause for each incident from the list of 52 items. Definition of serious hypotension, serious hypoxemia and others was those events suggesting the possibility of impending cardiac arrest or permanent disability of the central nervous system or myocardium. The respondents were also requested to submit the tabulation of patients by ASA physical status, age distribution, surgery sites and anesthetic methods. Analysis was made by total incidents under anesthesia/surgery, and also by incidents totally attributable to anesthetic management (AM), due to preoperative complications (PC), due to intraoperative pathological events (IP) and due to surgery (SG). This paper focused on analysis of entire patients, as other later papers will report analyses with special reference to ASA physical status, age distribution, surgery sites and anesthetic methods. Total incidence of cardiac arrest under anesthesia/surgery was 6.12 per 10,000 anesthetics. PC, IP and SG occupied 47.2%, 21.1% and 24.2% of principal causes of total cardiac arrest, respectively. AM occupied only 6.4% of the principal causes and the incidence was 0.39 per 10,000. The most frequent cause of cardiac arrest in 52 more detailed classifications of principal causes was preoperative hemorrhagic shock that occupied 19.2% of all cardiac arrests. The second was massive hemorrhage due to surgical procedures (12.3%), and the third was surgery itself (9.7%). Prognosis of the cardiac arrest was worst in that due to PC, i.e. 86.1% of cardiac arrests died in the operating room or within 7 days after surgery and only 5.3% survived without sequelae. Very low survival rate of preoperative hemorrhagic shock (5.3%) and preoperative multiple organ failure/sepsis (7.1%) aggravated the prognosis. Pulmonary embolism was the worst single cause in prognosis of cardiac arrest due to IP. The best prognosis was found in cardiac arrest due to AM, 82.0% survived without sequelae and 10.0% died. The mortality rate after cardiac arrest was 3.04 per 10,000 anesthetics, of them 0.04 was due to AM, 0.43 due to IP, 1.89 due to PC and 0.67 due to SG. The mortality rate after critical incidents other than cardiac arrest such as severe hypotension and severe hypoxemia was 3.37, and of them 0.06 was due to AM, 0.23 due to IP, 2.25 due to PC and 0.82 due to SG. The final mortality rate attributable to anesthesia/surgery including deaths after cardiac arrest and after other critical incidents was 6.41 per 10,000 anesthetics. The final mortality rate totally attributable to AM was 0.10 per 10,000 anesthetics, which was significantly improved from 0.21 [0.15, 0.27], that of mean [95%C.I.] in 1994-1998. IP, PC and SG showed the final mortality rate of 0.65, 4.14 and 1.49, respectively. Three major causes of all critical incidents in 52 detailed classification of principal causes were preoperative hemorrhagic shock (31.4%), massive hemorrhage due to surgical procedures (16.9%), and preoperative multiple organ failure/sepsis (9.0%). In conclusion, the obtained incidences as to cardiac arrest and death, either in total number during anesthesia/surgery or in that due to anesthetic management, kept decreasing lineally through 8 years study in 1994-2001. We expect that this second series of annual studies for five-years should reveal precise and definite direction for us to reduce anesthesia-related mortality and morbidity by analyzing further detail with special reference to ASA physical status, age distribution, surgery sites and anesthetic methods.