[A comment on five reports concerning perioperative mortality and morbidity of the year 1999 in Japanese Society of Anesthesiologists certified training hospitals].

Japanese Society of Anesthesiologists (JSA) has conducted an annual survey concerning anesthesia-related morbidity and mortality in JSA certified training hospitals. This survey was conducted through confidential questionnaires sent by mail to the hospitals. In 'Survey 1999', 60.3% of the hospitals responded to the questionnaire. The results were published in five separate reports: with special reference to ASA-physical status, age, anesthetic methods, operative regions, and 'outline'. However, overall morbidity and mortality differed among the reports. For example, overall anesthesia-related morbidity in the report with special reference to ASA-PS was 0.08 (5/655,644) per 10,000 cases, although it was 0.13 (11/793,847) in a report 'outline'. This difference was caused by imperfect answers from some hospitals. Some hospitals only reported the total number of patients in 1999 and total cases with cardiac arrest or other critical events, without details of distribution as to ASA-physical status, age, anesthetic methods, and/or operative regions. As a result, a part of critical incidents was reflected in the calculation of overall mortality and morbidity in the 'outlines', but not in that of ASA-physical status, age, anesthetic methods, and/or operative regions. In 'Survey 2000', however this type of confusion was reduced, because increasing number of hospitals had answered the questionnaire completely.