Comparative study between dexmedetomidine-ketamine and fentanyl-ketamine combinations for sedation in patients undergoing extracorporeal shock wave lithotripsy. A randomized double blinded study

Intravenous Dexmedetomidine-Ketamine Versus Ketamine-Propofol for Procedural Sedation in Adults Undergoing Short Surgical Procedures: A Randomized Controlled Trial

Background and objective Moderate to deep sedation is a prerequisite during total intravenous anesthesia for short-duration surgeries, and it can be achieved by using individual drugs or in combination. Our study compared dexmedetomidine-ketamine (DK) versus ketamine-propofol (KP) in terms of sedation, procedural interference, hemodynamics, and incidence of side effects in patients undergoing short surgical procedures. Methods A total of 194 patients scheduled for short-duration elective surgeries were randomly allocated into two groups. Group DK received a loading dose of 1 µg/kg of dexmedetomidine and 1 mg/kg of ketamine followed by a maintenance infusion of dexmedetomidine at 0.3 µg/kg/h. Group KP received a loading dose of 1 mg/kg of ketamine and 1 mg/kg of propofol followed by a maintenance infusion of propofol at 25 µg/kg/h. For procedural interference, a rescue ketamine bolus was administered at 0.25 mg/kg. Patients were monitored for the requirement of rescue ketamine bolus, procedural interference, hemodynamics, sedation, recovery time, and adverse effects. Results The procedural interference was higher in group KP than in group DK and the difference was statistically significant (P=0.001). The time to the first rescue bolus was 8.72 ± 4.47 minutes in group KP and 10.82 ± 4.01 minutes in group DK, with a difference of 2.1 minutes (p=0.026). There was no statistically significant difference in the sedation scores between both groups except at time points of six minutes and 15 minutes. Conclusion For short-duration procedures, the DK combination is superior to the KP combination in terms of procedural interference and time to the first rescue bolus, while both groups were comparable with regard to safety and hemodynamics.

Neurocognitive performance under combined regimens of ketamine-dexmedetomidine and ketamine-fentanyl in healthy adults: A randomised trial

Analgesic doses of ketamine affects neurocognition; however, deficits under co-administration regimens are unknown. This study evaluated the effects of ketamine, alone and in combination with dexmedetomidine or fentanyl on neurocognition. Using a randomised, within-subjects gender stratified design, 39 participants (mean age = 28.4, SD ± 5.8) received a ketamine bolus of 0.3 mg/kg followed by 0.15 mg/kg/h infusion of ketamine (3 h duration). At 1.5 h post-ketamine infusion commencement, participants received either: i) 0.7 μg/kg/h infusion of dexmedetomidine (n = 19) (KET/DEX) or (ii) three 25 μg fentanyl injections over 1.5 h (n = 20) (KET/FENT). Reaction and Movement time (RTI, Simple and 5Choice), Visuospatial Working Memory (SWM) and Verbal Recognition Memory (VRM) were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Whole blood drug concentrations were determined during ketamine-only infusion, at co-administration (KET/DEX or KET/FENT) and at 2-h post-treatment. Ketamine-only administration impaired psychomotor response speed (Simple and 5Choice) and impaired memory (all p < .001), however did not alter executive function abilities. Independent of sedation, co-administration of dexmedetomidine produced synergistic performance and memory deficits which persisted at post-treatment (KET/DEX) (all p < .001), and were comparatively greater than for KET/FENT (all p < .05). Ketamine, norketamine and dexmedetomidine concentrations were modestly associated with reduced psychomotor speed and accuracy (all p < .05), and an inverse relationship was found between blood concentrations of ketamine, norketamine and dexmedetomidine and performance on memory tasks. Co-administration of ketamine with dexmedetomidine but not with fentanyl exerts synergistic effects on psychomotor performance and memory without executive dysfunction. Assessment of these effects in clinical groups is warranted.