Deaths in Incorrectly Identified Low-Surgical-Risk Patients

The American Society of Anesthesiologists (ASA) physical classification system was developed for assessing anaesthetic risk, but is often also used to estimate surgical death risk. Patients with low ASA grades (ASA 1 or 2) are expected to have better surgical outcomes than patients with higher ASA grades (ASA ≥ 4). This study examined the course to death in patients classified as ASA 1 or 2 was examined, to investigate possible factors in unexpected deaths, in addition to evaluating the use of ASA grades by clinicians.

Patient data from the national surgical mortality audit of Australian hospitals were examined. The patient group was listed as ASA grade 1 or 2 by surgeons. Patients over 60 or under 20 were excluded in the final analysis, as were cases from New South Wales due to data not being available. A total of 357 cases were examined. Assessor summaries of the cases were examined, and ASA score reassessed to determine accuracy.

More than 95% (n = 339) of cases listed as ASA 1 or 2 were found to have an incorrectly low grade, with 17.6% (n = 63) of cases listed as "expected" deaths.

ASA grades appear to be misunderstood in the reporting of patient surgical risk. Many patient summaries list patients with severe systemic disease or expected deaths as ASA 1 or 2, contrary to the intended use of this classification system. Improved education on the use of the ASA grading system would be beneficial to clinicians.