A Prospective Randomised Controlled Study Comparing Clinical Effects of Intraoperative Dexmedetomidine with Ketamine or Fentanyl as Adjuvants during General Anaesthesia
Background and Introduction: Balanced general anaesthesia employing adjuvant drugs allows reduction in primary anaesthetic doses while achieving haemodynamic stability, analgesia, and smooth recovery. Dexmedetomidine, a selective α₂-adrenoceptor agonist, is widely used as an intraoperative adjuvant for its sympatholytic, sedative, and analgesic properties. When combined with ketamine—an NMDA receptor antagonist with sympathomimetic properties—or fentanyl—a potent µ-opioid agonist—distinct haemodynamic and recovery profiles may result. Comparative evidence directly evaluating these two combinations in the intraoperative general anaesthesia setting remains limited, necessitating the present study. Aim: To compare the clinical effects of dexmedetomidine with ketamine versus dexmedetomidine with fentanyl as intraoperative adjuvants during general anaesthesia in terms of haemodynamic parameters, recovery characteristics, anaesthetic requirements, postoperative analgesia, and adverse events. Methods: A prospective randomised controlled study was conducted in 54 ASA I–II adult patients undergoing elective surgery under general anaesthesia. Patients were randomised equally into Group DK (dexmedetomidine + ketamine, n = 27) and Group DF (dexmedetomidine + fentanyl, n = 27). Heart rate, mean arterial pressure, SpO₂, and EtCO₂ were monitored at multiple intraoperative and postoperative time points. VAS pain scores were assessed at the end of surgery and at 2, 4, and 6 hours postoperatively. Muscle relaxant dose, extubation time, Ramsay Sedation Score, PACU stay duration, and adverse events were recorded. Data were analysed using independent samples t-test and chi-square/Fisher's exact test. p < 0.05 was considered statistically significant. Results: Both groups were comparable at baseline for all demographic variables (p > 0.05). Heart rate was comparable up to 40 minutes but was significantly higher in Group DK from 65 minutes onward, at extubation (69.30 ± 6.80 vs 62.11 ± 4.56 bpm; p < 0.001), and at 2 hours postoperatively (70.89 ± 6.38 vs 61.93 ± 4.95 bpm; p < 0.001). MAP was comparable through 125 minutes but significantly higher in Group DK from 140 minutes onward, at extubation (79.56 ± 5.42 vs 74.59 ± 6.70 mmHg; p = 0.004), and at 2 hours postoperatively (82.93 ± 7.99 vs 77.19 ± 9.26 mmHg; p = 0.018). SpO₂ and EtCO₂ were comparable throughout. VAS scores were similar at end of surgery and 2 hours, but significantly lower in Group DK at 4 hours (1.67 ± 0.78 vs 3.89 ± 0.85; p < 0.001) and 6 hours (1.78 ± 0.80 vs 4.44 ± 1.09; p < 0.001). Group DF required a significantly higher muscle relaxant dose (4.07 ± 0.87 vs 3.63 ± 0.69 mg; p = 0.043). Extubation time and Ramsay Sedation Scores were comparable. PACU stay was significantly prolonged in Group DF (p = 0.001). All adverse events were infrequent with no statistically significant intergroup differences. Conclusion: Dexmedetomidine with ketamine provides superior intraoperative haemodynamic stability, reduced muscle relaxant requirement, and significantly better postoperative analgesia at 4 and 6 hours compared to dexmedetomidine with fentanyl, along with a shorter PACU stay. Both combinations demonstrated comparable and acceptable safety profiles. The choice of adjuvant combination should be individualised based on surgical requirements, expected postoperative pain, and recovery logistics.