The Epidemiology of Major Early Adverse Physiological Events After Surgery

OBJECTIVE: To study the incidence of major post-operative adverse physiological events in a tertiary hospital. METHODS: Non-cardiac, surgical in-patients were studied for the first three post-operative days. Daily assessment was by patient visit, chart review and laboratory result analysis. Pre-determined diagnostic criteria for the identification of adverse physiological events were used. RESULTS: One hundred and seven patients were studied. The mean age was 61 +/- 20 years. Forty-four were female and 63 were male. Pre-operatively, 48 patients had one or more of 34 different co-morbidities. Forty three (40%) of the 107 patients had one or more major adverse physiological events. These events included hypotension 24 (22%), altered mental state 16 (15%), oliguria 9 (8.4%), abnormal heart rate 8 (7.5%) and abnormal respiratory rate 5 (4.7%). Morbidity associated with these events included respiratory failure 5 (4.7%), prolonged altered mental state 5, (4.7%), and septic shock 3 (2.8%). There were two deaths. Adverse physiological events were common in thoracic 5/9 (56%), neurosurgical 4/10 (40%) and vascular 8/13 (62%) patients. Prolonged altered mental state was most common among orthopaedic patients 5/22 (23%). Adverse physiological events were more frequent in the elderly than the young: 14/52 (27%) in those who were less than 65 years of age versus 29/55 (53%) in those who were 65 years and older (p < 0.025). There was a non-significant increase (p < 0.1) in adverse physiological events in patients having emergency surgery 16/28 (57%) compared with those having elective surgery 27/79 (34%). CONCLUSIONS: This study reveals a high incidence of post-operative adverse physiological events in surgical patients in a university teaching hospital and identifies several high-risk groups. Further studies are needed to define the clinical significance of these events, appropriate management and prognosis.