Sedative and analgesic validity and administration routes of dexmedetomidine and fentanyl combined with ketamine in awake fiberoptic intubation: An exploratory randomized controlled trial

Abstract Background: Awake fiberoptic bronchoscope intubation (AFOBI) is the gold standard technique for the management of patients with difficult airways. Adequate sedation and analgesia are essential for successful AFOBI. The aim of this study was to evaluate the sedative and analgesic validity and administration routes of dexmedetomidine and fentanyl combined with ketamine in awake fiberoptic intubation.Methods: Patients undergoing head and neck surgery under general anesthesia with predicted difficult airways were included. Participants were randomly assigned to 6 different groups (n = 6): groups 1-3 were intravenous (IV), while groups 4-6 were intranasal (IN) (group 1: dexmedetomidine (DEX) 1 μg/kg + fentanyl (FEN) 1 μg/kg; groups 2-3: DEX 1 μg/kg + FEN 0.7 μg/kg + ketamine (KTM) 0.1/0.2 mg/kg; group 4: DEX 1.5 μg/kg + FEN 1.4 μg/kg; and groups 5-6: DEX 1 μg/kg + FEN 1 μg/kg + KTM 0.4/0.6 mg/kg). The visual analog scale (VAS) score during intubation, time required for the modified observer’s assessment of alertness/sedation scale (OAA/S) score to reach above 2 and for the bispectral index (BIS) to decrease to 60-80, motor activity assessment scale (MAAS) score, changes in vital signs and adverse effects were recorded.Results: Among the IV groups, the VAS score of group 1 (5.65 ± 2.11) was higher than those of group 2 (1.89 ± 2.16, P = 0.012) and group 3 (1.15 ± 0.98, P = 0.001). Among the IN groups, the VAS score was lower in group 6 (0.86 ± 1.27) than in group 4 (7.20 ± 2.70, P < 0.001) and group 5 (3.93 ± 2.73, P = 0.031). Participants in group 5 and group 6 were less likely to cough when intubated than those in group 4 (P = 0.002), while the differences among IV groups were not significant. There were no significant differences in the other endpoints.Conclusions: Our study indicates that the addition of subanesthetic doses of ketamine, either intravenous or intranasal, could reduce the fentanyl and dexmedetomidine consumption used in AFOBI and provide better sedative and analgesic effects.Trial registration: Chinese Clinical Trial Registry (www.chictr.org.cn; ChiCTR1900021185), prospectively registered on February 1st, 2019.