Evaluation of paradoxical effect of small dose ketamine as adjuvant in deep sedation for endoscopy patients

Background This study tested the hypothesis that use of ketamine as an ‎adjuvant to propofol in the induction of deep sedation for ‎endoscopy patients could lead, paradoxically, to faster ‎emergence.‎Methods We conducted a single-center, prospective randomized ‎controlled study on 154 adult ASA I or II patients‎, admitted for ‎gastrointestinal endoscopies‎. Patients were sedated with 25 µg ‎fentanyl and 1 mg/kg propofol bolus over 30 s. Patients ‎were divided into two groups: Group P (n = 77), sedated with ‎propofol only, and Group PK (n = 77), who received additionally a ‎single dose of ketamine (0.1 mg/kg) at induction. If the patient ‎moved or Ramsay Sedation Score (RSS) regressed to <4, ‎increments of 0.25 mg/kg of propofol were given. After the end ‎of the procedure, emergence from sedation was assessed with ‎modified Aldrete score, 5 and 10 m after admission to the ‎recovery room.‎Results Adding a small dose of ketamine did not significantly achieve ‎deep sedation (RSS ≥4) more quickly or result in lesser ‎propofol increments. Patients who received ketamine showed a ‎statistically significant improvement in the Modified Aldrete ‎score when recorded 5 min after admission to the recovery ‎room (Group P 8.73 ± 1.02, Group PK 9.1 ± 0.96, P value = ‎‎0.02), but not after 10 min (Group P 9.03 ± 0.74, Group PK ‎‎9.21 ± 0.8, P value = 0.146).‎Conclusion Inclusion of a small single dose of ketamine in the induction of sedation for gastrointestinal endoscopy significantly improves emergence from sedation.