Intraoperative vasopressor use and early postoperative acute kidney injury in elderly patients undergoing elective noncardiac surgery

Background Intraoperative hypotension is a risk factor for postoperative acute kidney injury (AKI). Elderly patients are susceptible due to reduced responses to acute hemodynamic changes. Aims Determine the association between hypotension identified from anesthetic charts and postoperative AKI in elderly patients. Methods Retrospective cohort study of elective noncardiac surgery patients >= 65 years, at an Australian tertiary hospital (December 2019-March 2021), with the primary outcome of AKI <= 48 h of surgery. Factors of interest were intraoperative hypotension determined from anesthetic charts (mean arterial pressure <60 mmHg, systolic blood pressure <90 mmHg, recorded 5-min) and intraoperative vasopressor use. Results In 830 patients (mean age 75 years), systolic hypotension was more frequent than mean arterial hypotension (25.7% vs. 11.9%). Most hypotensive episodes were brief (7.2% of systolic and 4.2% of mean arterial hypotension lasted >10 min) but vasopressors were used in 84.7% of cases. The incidence of postoperative AKI was 13.9%. Systolic hypotension >20 min was associated with AKI (OR, 3.88; 95% CI: 1.38-10.9), which was not significant after adjusting for vasopressors, creatinine, American Society of Anesthesiologists class, and hemoglobin drop. The cumulative dose of any specific vasopressor >20 mg (or >10 mg epinephrine) was independently associated with AKI (adjusted OR, 2.47; 95% CI: 1.34-4.58). Every 5 mg increase in the total dose of all intraoperative vasopressors used during surgery was associated with 11% increased odds of AKI (95% CI: 3-19%). Conclusions High vasopressor use was associated with postoperative AKI in elderly patients undergoing noncardiac surgery, independent of hypotension identified from anesthetic charts.