Discharge Readiness after Propofol with or without Dexmedetomidine for Colonoscopy

BACKGROUND: Enhanced recovery protocols employ various approaches to minimize detrimental side effects of anesthetizing agents. The authors tested the hypothesis that adding low-dose dexmedetomidine to propofol for anesthesia in ambulatory colonoscopies, compared with propofol alone, would lower the propofol requirement, improve the intra-procedure hemodynamic state, and not increase time-to-discharge. METHODS: In this noninferiority, double-blind, randomized controlled trial, patients having colonoscopies received total IV anesthesia either with propofol and placebo (n = 50), or propofol and a bolus dose of dexmedetomidine, 0.3 μg/kg (n = 51). Additional propofol was administered to maintain a Bispectral Index score of 60. Following the procedure, readiness for discharge was assessed regularly using the Modified Post Anesthetic Discharge Scoring System until discharge criteria were met. The primary outcome was the percentage of patients meeting discharge criteria within 30 min from procedure end-time. RESULTS: Twenty-six of 51 (51%) patients receiving propofol-dexmedetomidine were ready for discharge by 30 min from procedure end time, compared with 44 of 50 (88%) receiving propofol (P < 0.001). Propofol consumption was lower in subjects receiving propofol-dexmedetomidine (140 μg · kg(-1) · min(-1)) compared to those receiving propofol (180 μg · kg(-1) · min(-1)) with P = 0.011. The lowest mean arterial pressure decreased further from baseline in those receiving propofol-dexmedetomidine (-30%; mean decrease -30 ±10.5 mmHg) compared to propofol (-21%; mean decrease, -22 ± 14.2 mmHg) with P = 0.003. There was no difference in incidence of bradycardia, with sustained bradycardia occurring in 3 of 51 (6%) patients receiving propofol-dexmedetomidine compared to 1 of 50 (2%) patients receiving propofol (P = 0.62). No apnea episodes requiring positive-pressure ventilation occurred in either group. CONCLUSIONS: For anesthesia in ambulatory colonoscopy, combining low-dose dexmedetomidine with propofol delayed discharge readiness and provoked hypotension compared to propofol alone.