Utility of preoperative laboratory testing in ASA 1 & ASA 2 patients undergoing outpatient surgery in the United States

Abstract

Study objectiveTo assess the utility of preoperative testing in ASA physical status 1 and 2 patients undergoing outpatient surgery across several surgical specialties. DesignRetrospective cohort study. PatientsThe American College of Surgeons National Surgical Quality Improvement Program database from 2017 to 2018 was queried to extract patients defined as ASA 1 and 2 who underwent outpatient surgeries. A total of 352,775 adult patients underwent outpatient surgery with 186,954 patients had at least one lab drawn within 30 days prior to the surgery. InterventionsASA physical status 1 and 2 patients who underwent outpatient surgeries. MeasurementsThe primary independent variable was the utilization of preoperative laboratory testing. The primary outcomes were the occurrence of any medical or surgical complication adverse events within 30 days of discharge. In addition, we also examined hospital readmissions. A P value of 0.025 was used to avoid type I error for each primary outcome. Main resultsIn the overall cohort, 186,954 out of 352,775 (53%) of patients had at least one lab test. Hematology was the most common lab test ordered, 172,903 out of 352,755 patients (49%), followed by chemistry (43%), liver function (23%), and coagulation tests (11%). After adjusting for confounding factors, the use preoperative testing was not associated with overall medical complications, OR (95%CI) of 1.09 (1.00 to 1.18), P = 0.05 and overall surgical complications, 1.00 (0.92 to 1.08), P = 0.96 [Bonferroni corrected: medical complications OR (97.5% CI) of 1.09 (0.989 to 1.202), P = 0.0950 and overall surgical complications, 1.00 (0.918 to 1.093), P = 1.00. ConclusionWe detected a low utility of preoperative tests for ASA 1 and 2 patients undergoing a large variety of outpatient procedures. Our results support the elimination of preoperative laboratory test for ASA 1 and 2 undergoing ambulatory surgery.