Optimal Propofol Concentration at Effect Site for Esophagogastroduodenoscopy under Moderate to Deep Sedation with Target-controlled Infusion

Abstract

Background: The target-controlled infusion (TCI) of propofol is being increasingly used for moderate-to-deep sedation during esophagogastroduodenoscopies (EGDs). Objective: To determine the target effect-site concentration (Cet) of propofol required for EGD scope insertions during sedation using TCI. Materials and Methods: Dixon’s up-and-down sequential allocation method was used with patients scheduled for elective EGD at Srinagarind Hospital, Thailand. The patients were divided into Group A aged 18 to 64 years and Group B aged over 65 years. Anesthesia was induced with propofol via TCI (Schnider model). The propofol Cet commenced at 3 mcg/mL and 2 mcg/mL in Groups A, and B, respectively. The response during an EGD scope insertion determined the Cet for the next patient, with intervals of 0.3 mcg/mL. Calculations of the effective concentration without response during EGD scope insertion in 50% and 95% of patients (EC50 and EC95) values of propofol, with 95% confidence intervals (CIs), were performed using the isotonic regression method. Results: Twenty-one and nineteen patients were enrolled in Groups A, and B, respectively. In Group A, the EC50 of propofol for EGD was 3.30 mcg/ mL (95% CI 3.05 to 3.55), while the EC95 was 3.75 mcg/mL (95% CI 3.34 to 4.16). In the case of Group B, the EC50 was 3.05 mcg/mL (95% CI 2.75 to 3.35) and the EC95 was 3.05 mcg/mL (95% CI 2.92 to 3.18). Hypotension occurred in 52.3% and 31.5% of patients in group A, and B, respectively. Conclusion: The appropriate Cet of propofol for anesthesia during EGD using TCI is 3.75 mcg/mL for patients aged 18 to 64 years, and 3.05 mcg/ mL for patients aged 65 years and over. Hypotension is the most common adverse event of moderate-to-deep sedation with propofol using TCI.