Preoperative Medication Management, Compliance and Adverse Events in Adult Patients Undergoing Elective Surgery: A Historical Chart Review

Purpose: Medication compliance for chronic medications has been well studied, but there is a gap in the literature regarding compliance within the perioperative period. Our objective was to determine the incidence of patient non-compliance with preoperative medication instructions for adult non-emergent surgery. Additional objectives were to identify predictors of compliance, describe medication instructions by drug type, and explore the impact of non-compliance. Patients and Methods: This historical chart review evaluated preoperative compliance to medication instructions in 393 adults undergoing non-emergent surgeries at Hamilton Health Sciences between May 1, 2012, and April 30, 2013. Seven patient factors (age; sex; American Society of Anesthesiologists class; number of medications; type of surgery; time between preoperative appointment to surgery; the individual collecting the medication list) were evaluated as potential predictors of non-compliance and analyzed using logistic regression analysis. Consequences of non-compliance were assessed by impact on intraoperative blood pressure, blood glucose level, drop in hemoglobin, bronchospasm, and case delays. Results: One hundred forty-six (37.2%) patients were non-compliant with one or more medication reconciliation instructions provided by the anesthesiologist. No significant associations were observed for any patient risk factors and non-compliance. Non-compliance was not associated with any clinically significant consequences. Conclusions: Our study shows that 37.15% of adult patients undergoing non-emergent surgery were non-compliant with medication instructions, although patients did not receive any written instructions for 46% of their medications. We did not identify any predictive patient factors or adverse outcomes associated with non-compliance.