Decreasing frequency of anesthetic cardiac arrests

To determine whether the anesthetic cardiac arrest rate decreased following the introduction of enhanced respiratory monitoring and increased safety awareness during the past decade.

Epidemiologic study of surgical anesthetic morbidity as represented by intraoperative cardiac arrests.

Operating room suite of a large university hospital.

241,934 patients undergoing surgery over a period of 20 years.

Anesthetic cardiac arrest rates from two decades were compared. The first decade (1969 to 1978) predated safety initiatives, while the second (1979 to 1988) included them.

Anesthetic cardiac arrests were identified, and their causes (respiratory vs nonrespiratory) and preventability (identifiable error) were determined shortly after their occurrence, as part of an ongoing study initiated in 1969. They provided numerators for rate calculations; total surgical anesthetics provided the denominators. The anesthetic cardiac arrest rate decreased by one-half from the first decade (2.1 arrests/10,000 anesthetics) to the second (1.0/10,000), a significant difference (p = 0.032, Fisher's Exact Test). The rate for preventable arrests due to respiratory causes declined significantly from 0.8/10,000 to 0.1/10,000 (p = 0.013) and accounted for most of the observed decrease in the overall anesthetic cardiac arrest rate. The rates for preventable nonrespiratory arrests and nonpreventable arrests did not change significantly.

The results support the hypothesis that improved respiratory monitoring was effective in decreasing anesthetic morbidity.