The propofol-sparing effect of intravenous lidocaine in elderly patients undergoing colonoscopy: a randomized, double-blinded, controlled study

Background Propofol provides a prominent sedation effect in colonoscopy. However, anesthesia and sedation induced with propofol in the elderly might result in cardiopulmonary complications, especially when it is combined with opoids in the regimen. This study aimed to test the hypothesis that the addition of intravenous lidocaine to propofol-based sedation could decrease the overall propofol requirement in elderly patients during colonoscopy while the procedural sedation satisfaction and the hemodynamic stability were not compromised. Methods Ninety-two patients undergoing colonoscopy were randomly enrolled into lidocaine+propofol (L + P) group or normal saline+propofol (NS + P) groups. Subjects received intravenous bolus of 1.5 mg/kg lidocaine followed by 4 mg kg(- 1) h(- 1) lidocaine continuous infusion in L + P group or equivalent volumes of normal saline for boluses and infusion in NS + P group. Anesthesia was induced with 2.5 mu g sufentanil followed by injection of 1.2 mg kg(- 1) propofol in all patients. A single supplemental bolus of 0.6 mg kg(- 1) propofol was administered whenever MOAA/S score > 1 or had body movement during the colonoscopy. The recorded primary endpoints included: the total amount of propofol administered during entire procedure, the supplemental amount of propofol after induction, and the frequencies of boluses of supplemental propofol. Results A total of 79 patients were included in the final analysis. Compared with NS + P group, the total amounts of propofol (induction plus supplemental) were no significant differences in L + P group; however, the required supplemental propofol was less (69.9 +/- 39.2 mg vs. 51.5 +/- 38.6 mg) (P = 0.039); the average frequencies of boluses of supplemental propofol given after induction were lower (2.1 +/- 1.1 vs. 1.4 +/- 0.9) (P = 0.003); the calculated "unit propofol" infusion rate was lower (0.18 +/- 0.05 vs. 0.14 +/- 0.04 mg kg(- 1) min(- 1)) (P = 0.002). Conclusions The addition of intravenous lidocaine to propofol-based sedation resulted in a remarked reduction of supplemental propofol in the elderly during colonoscopy.