RESUMO
BACKGROUND AND PURPOSE: PECs blocks are usually combined for breast surgery under general anesthesia (GA) to provide postoperative analgesia rather than primary anesthesia technique. MATERIAL AND METHODS: A prospective, interventional, single-center, double-blind, randomized, parallel-group, active-controlled, Helsinki protocol-compliant clinical study was conducted in a tertiary care teaching center after obtaining the Ethics Committee's approval and patients' written informed consent. Forty-eight American Society of Anesthesiologists physical status I/II patients aged 18-60 years, undergoing elective unilateral breast surgery were enrolled. Patients were block-randomized (computer-generated) to two equal groups (24 patients each), with one of them receiving Dexmedetomidine and the other one Ketamine. For concealment, sequentially numbered, sealed, opaque envelopes were used. The study was double-blinded for both the anesthesiologist and outcome assessor anesthesiologist. Obese patients (body mass index > 30), those with infection at block site, coagulopathy and known hypersensitivity to local anesthetics or study medications as well as individuals who refused participation in research were all excluded. The Dexmedetomidine group received a bolus of 0.5 mcg/kg over ten minutes, followed by an infusion of 0.3 mcg/kg/hour, while the Ketamine group received a bolus of 0.5 mg/kg over ten minutes, followed by an infusion of 0.3 mg/kg/hour. Postoperative analgesia was compared using a visual analogue scale (VAS) at regular intervals. When VAS exceeded four, 1 mg/kg intravenous Pethidine was administered as a rescue analgesic. RESULTS: Sub-anesthetic low-dose Ketamine was more effective than low-dose Dexmedetomidine in prolonging PECs block analgesia, which was statistically significant (p value < 0.001). The Ketamine group had lower rescue analgesic Pethidine consumption and longer first-rescue analgesia demand time. There was no significant hemodynamic difference between the study groups. CONCLUSION: Ketamine was more efficient than Dexmedetomidine for postoperative analgesia.