Postoperative serious adverse events in a teaching hospital: a prospective study

Objective: To assess the incidence and nature of postoperative serious adverse events (SAEs) among inpatients having surgery in a tertiary hospital, and to determine which subgroups of patients might be at greatest risk. Design: Prospective observational study from 1 December 1998 - 31 March 1999. Setting: Tertiary teaching hospital in Melbourne, Victoria. Subjects: 1125 subjects having inpatient surgery during the study period. Main outcome measures: Inhospital mortality, length of hospital stay, and SAEs (myocardial infarction, pulmonary embolism, acute pulmonary oedema, unscheduled tracheostomy, respiratory failure, cardiac arrest, stroke, severe sepsis, acute renal failure, and emergency admission to intensive care unit [ICU]). Results: There were 414 SAEs in 190 of the 1125 patients (16.9%); 80 patients died (7.1%). The most common adverse events were emergency admission to ICU (95), respiratory failure (52) and readmission to ICU (37). In patients without SAEs, mean duration of hospital stay was 18.4 days (95% Cl, 15.4-21.4), while in those with SAEs it was 38.5 days (95% Cl, 35.3-41.7) (P < 0.0001). SAEs, including deaths, were more common after unscheduled surgery and in patients over 75 years of age. The combination of these two factors carried a 20% mortality. There were no differences in the incidence of SAEs among the major surgical specialties. Conclusions: SAEs are common and result in high mortality, especially in older surgical inpatients and those having unscheduled surgery. These findings raise important issues of optimal perioperative management in tertiary hospitals.