title: Addition of sub-anaesthetic dose of ketamine reduces gag reflex during propofol based sedation for upper gastrointestinal endoscopy: A prospective randomised double-blind study.
abstract: OBJECTIVE
  Gag reflex is unwanted during upper gastrointestinal endoscopy (UGIE). Experimental studies have demonstrated that N-methyl-D-aspartate receptor antagonism prevents gag reflex. We conducted a study to determine if sub-anaesthetic doses of ketamine, added to propofol, reduce the incidence of gag reflex.
  
  
  METHODS
  This prospective, randomised, double-blind and placebo-controlled study was done in a tertiary care hospital. A total of 270 patients undergoing UGIE, were randomised to propofol (P) group (n = 135) or propofol plus ketamine (PK) group (n = 135). All patients received propofol boluses titrated to Ramsay sedation score of not <4. Patients in PK group in addition received ketamine, 0.15 mg/kg immediately before the first-propofol dose. Top-up doses of propofol were given as required. Stata 11 software (StataCorp.) was used to calculate the proportion of patients with gag reflex and the corresponding relative risk. Propofol consumed and time to recovery in the two groups was compared using Student's t-test and Cox proportional hazards regression respectively.
  
  
  RESULTS
  Significantly, fewer patients in the PK group had gag reflex compared to the P group (3 vs. 23, risk ratio = 0.214, 95% confidence interval [CI], 0.07-0.62; P = 0.005). The incidence of hypotension (6 vs. 16, risk ratio = 0.519, 95% CI = 0.25-1.038; P = 0.06), number of required airway manoeuvres (4 vs. 19, risk ratio = 0.32, 95% CI = 0.13-0.74; P = 0.014), median time to recovery (4 min vs. 5 min, hazard ratio = 1.311, 95% CI = 1.029-1.671; P = 0.028) and propofol dose administered (152 mg vs. 167 mg, 95% CI = 4.74-24.55; P = 0.004) was also less in the PK group compared to the P group.
  
  
  CONCLUSIONS
  Ketamine in sub-anaesthetic dose decreases gag reflex during UGIE.
authors.affiliation: Department of Anaesthesia, Institute of Liver and Biliary Sciences, New Delhi, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Tandon
authors.affiliation: Department of Anaesthesia, Institute of Liver and Biliary Sciences, New Delhi, India.
authors.forename: Vijay Kant
authors.initials: VK
authors.lastname: Pandey
authors.affiliation: Department of Anaesthesia, Institute of Liver and Biliary Sciences, New Delhi, India.
authors.forename: Gaurav Kumar
authors.initials: GK
authors.lastname: Dubey
authors.affiliation: Department of Anaesthesia, Institute of Liver and Biliary Sciences, New Delhi, India.
authors.forename: Chandra Kant
authors.initials: CK
authors.lastname: Pandey
authors.affiliation: Pediatric Biology Centre, Translational Health Science and Technology Institute, Gurgaon, Haryana, India.
authors.forename: Nitya
authors.initials: N
authors.lastname: Wadhwa
keywords: Endoscopy; gag reflex; ketamine