HYPOTENSION AFTER NONCARDIAC SURGERY

Abstract

BACKGROUND: Early postoperative cardiovascular complication rates are high and are associated with hemodynamic compromise. A large proportion of hypotensive episodes are missed with routine ward monitoring strategies due to low measurement frequency and nursing limitations. OBJECTIVES: The aim of this study was to determine the incidence of postoperative hypotension using a frequent monitoring strategy. Second, we looked at the relationship between postoperative hypotension and composite of mortality, non-fatal myocardial infarction, non-fatal stroke and new dialysis requirements. Finally, we sought to uncover significant predictors of postoperative hypotension. METHODS: Patients >45-years of age enrolled in the VISION Study were included in this sub-study. The COVIDIEN vital sign monitor was used to collect blinded hourly blood pressure measurements in patients post non-cardiac surgery until post-operative day three. RESULTS: 1248 patients were included in this analysis. The three-day incidence of hypotension in the compliant intensively monitored group was almost twice higher (31.4% - 81/258 patients) than in the routine monitoring group, and the average delay in identifying a drop in BP under 90mmHg was almost 1.5 hours (87.5min) (IQR 21.3-153.3min). Severe hypotension (SBP <80mmHg) in the first three postoperative days, had the strongest association amongst all perioperative factors with the composite outcome of death, MI, stroke and new requirement for dialysis after non-cardiac surgery at 30 days [adjusted OR of 2.83 (95%CI, 1.25-6.44)]. Significant predictors of postoperative hypotension include a history of dialysis [adjusted OR 3.1 (95%CI, 1.14-12.96)], open surgery [adjusted OR 2.39 (95%CI, 1.57-3.62)], abdominal surgery [adjusted OR 1.79 (95%CI, 1.25-2.57)], and orthopedic surgery [adjusted OR 1.72 (95%CI, 1.112.74)]. CONCLUSION: Early postoperative cardiovascular complication rates are high and are associated with hemodynamic compromise. A large proportion of hypotensive episodes are missed with routine ward monitoring strategies.