The effect of Dexmedetomidine or Midazolam-Fentanyl combination on block onset and duration in ultrasound-guided supraclavicular block

In our study, we aimed to compare the effects of dexmedetomidine or midazolam-fentanyl combination used as sedative agents on the onset and duration of block in patients undergoing supraclavicular block. After obtaining the approval of the Ethics Committee, 52 patients aged 18-65 years, ASA 1-2, scheduled for elective upper extremity surgery were randomly divided into two groups after written informed consent was obtained. Group MF patients received a loading dose of midazolam and a single injection of fentanyl and Group D patients received a loading dose of dexmedetomidine before the block was performed. Supraclavicular block was performed after loading doses. Sedative agents were given as infusion until the end of the operation and drug doses were adjusted every 10 min as Ramsey Sedation Scale 3-4. Perfusion index and extremity temperatures were recorded at 0, 10, 20 and 30 min in both extremities. Pinprick test for the onset of sensory block, Modified Bromage Scale for the onset of motor block, duration of sensory and motor block, duration of the first analgesic drug in the postoperative period, number of complications and patient satisfaction were recorded. PI and temperature increases were similar in Group MF and Group D patients and there was no significant difference. Sensory block onset time (11.49±2.54 vs. 8.32±2.08 min) and motor block onset time (15.03±2.62 vs. 11.37±2.44 min) were shorter in Group D (p<0,001). Sensory block duration (470±86 vs. 576±114 min) were longer in Group D patients (p<0.001). Motor block duration (353±58 vs. 426±96 min) were longer in Group D patients (p=0.005). The duration of the first postoperative analgesic drug was significantly longer in Group D patients (p=0,01). There was no significant difference between complications and patient satisfaction. In conclusion; Dexmedetomidine shortens the block onset time, prolongs the block duration and prolongs the need for initial postoperative analgesic medication. Key words: Supraclavicular Block, Sedation, Dexmedetomidine, Midazolam, Fentanyl