A randomized controlled trial of light versus deep propofol sedation for elective outpatient colonoscopy: recall, procedural conditions, and recovery.
OBJECTIVE
This study aimed to determine if the incidence of recall was equivalent between light and deep sedation for colonoscopy. Secondary analysis included complications, patient clinical recovery, and post-procedure cognitive impairment.


METHODS
Two hundred patients undergoing elective outpatient colonoscopy were randomized to light (bispectral index [BIS] 70-80) or deep (BIS < 60) sedation with propofol and fentanyl. Recall was assessed by the modified Brice questionnaire, and cognition at baseline and discharge was assessed using a Cogstate test battery.


RESULTS
The median (interquartile range [IQR]) BIS values were different in the two groups (69 [65-74] light sedation vs 53 [46-59] deep sedation; P < 0.0001). The incidence of recall was 12% in the light sedation group and 1% in the deep sedation group. The risk difference for recall was 0.11 (90% confidence interval, 0.05 to 0.17) in the intention-to-treat analysis, thus refuting equivalence in recall between light and deep sedation (0.05 significance level; 10% equivalence margin). Overall sedation-related complications were more frequent with deep sedation than with light sedation (66% vs 47%, respectively; P = 0.008). Recovery was more rapid with light sedation than with deep sedation as determined by the mean (SD) time to reach a score of 5 on the Modified Observer's Assessment of Alertness/Sedation Scale [3 (4) min vs 7 (4) min, respectively; P < 0.001] and by the median [IQR] time to readiness for hospital discharge (65 [57-80] min vs 74 [63-86] min, respectively; P = 0.001). The incidence of post-procedural cognitive impairment was similar in those randomized to light (19%) vs deep (16%) sedation (P = 0.554).


CONCLUSIONS
Light sedation was not equivalent to deep sedation for procedural recall, the spectrum of complications, or recovery times. This study provides evidence to inform discussions with patients about sedation for colonoscopy. This trial was registered at the Australian and New Zealand Clinical Trials Registry, number 12611000320954.
Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne, Australia. meganliseallen@gmail.com.|Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Melbourne, Australia. meganliseallen@gmail.com.
Megan
http://orcid.org/0000-0001-5614-0799
M
Allen
Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne, Australia.|Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Melbourne, Australia.|Department of Pharmacology, University of Melbourne, Melbourne, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
Kate
K
Leslie
Department of Gastroenterology, Royal Melbourne Hospital, Melbourne, Australia.|Department of Medicine, University of Melbourne, Melbourne, Australia.
Geoffrey
G
Hebbard
Colorectal Surgery Unit, Royal Melbourne Hospital, Melbourne, Australia.|Department of Surgery, University of Melbourne, Melbourne, Australia.
Ian
I
Jones
Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne, Australia.|Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Melbourne, Australia.
Tejinder
T
Mettho
Cogstate Ltd, Melbourne, Australia.|Centre for Neuroscience, University of Melbourne, Melbourne, Australia.
Paul
P
Maruff
D000762:Anesthesia Recovery Period; D018686:Anesthetics, Intravenous; D003113:Colonoscopy; D016292:Procedural Sedation / Q000379:methods*; D054810:Deep Sedation / Q000379:methods*; D017558:Elective Surgical Procedures; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000187:drug effects*; D008875:Middle Aged; D010045:Outpatients / Q000706:statistics & numerical data; D015742:Propofol
D018686:Anesthetics, Intravenous; D015742:Propofol