Intranasal Dexmedetomidine Reduces Postoperative Opioid Requirement in Patients Undergoing Total Knee Arthroplasty Under General Anesthesia.

BACKGROUND: Total knee arthroplasty (TKA) causes severe pain, and strong opioids are commonly used in postoperative analgesia. Dexmedetomidine is a novel alpha-2-adrenoceptor-activating drug indicated for procedural sedation, but previous studies have shown clinically relevant analgesic and antiemetic effects. We evaluated retrospectively the effect of intranasal dexmedetomidine on the postoperative opioid requirement in patients undergoing TKA. METHODS: One hundred and fifty patients with ASA status 1-2, age between 35 and 80 years, and scheduled for unilateral primary TKA under total intravenous anesthesia were included in the study. Half of the patients received 100 µg of intranasal dexmedetomidine after anesthesia induction, while the rest were treated conventionally. The postoperative opioid requirement was calculated as morphine equivalent doses for both groups. The effect of dexmedetomidine on postoperative hemodynamics, length of stay (LOS), and incidence of postoperative nausea and vomiting (PONV), was evaluated. RESULTS: The cumulative postoperative opioid consumption was significantly reduced in the dexmedetomidine group compared to the control group (-28.5 mg, 95% CI 12-47 mg P < .001). The reduction in cumulative opioid dose was significantly different between the groups already at 2, 12, 24, and 36 h postoperatively (P < .001). LOS was shorter in the dexmedetomidine group (P < .001), and the dexmedetomidine group had lower postoperative mean arterial pressure and heart rates were lower compared to the control group (P < .001). The incidence of PONV did not differ between the groups (P = .64). CONCLUSION: Intraoperatively administered intranasal dexmedetomidine reduces postoperative opioid consumption and may be associated with a shorter hospital stay in patients undergoing TKA under general anesthesia.

Feasibility of Intranasal Dexmedetomidine in Treatment of Postoperative Restlessness, Agitation, and Pain in Geriatric Orthopedic Patients.

OBJECTIVE: The aim of this study was to report preliminary data on the use of intranasal dexmedetomidine to treat postoperative restlessness, agitation, and pain in 23 patients aged > 70 years and undergoing orthopedic surgery. BACKGROUND: Postoperative agitation and delirium are common among older adult patients undergoing orthopedic surgery. Most preparations used to treat agitation and delirium carry a risk for adverse events such as respiratory failure. Moreover, mere opioid therapy may be insufficient in treatment of pain. Dexmedetomidine, an α2-adrenoreceptor agonist with sedative and analgesic properties, has been shown to reduce opioid requirement and reduce postoperative delirium in older adults. METHODS: We studied the use of post-operative intranasal dexmedetomidine in a retrospective study cohort of geriatric patients undergoing orthopedic surgery. Primary outcomes included alterations in heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), peripheral oxygen saturation (SpO2), Modified Richmond Agitation and Sedation Score (mRASS), and opioid consumption following dexmedetomidine administration. RESULTS: We identified 23 patients with a mean (SD) age of 79.9 (7.5) years who received dexmedetomidine 100 µg intranasally postoperatively. After dexmedetomidine administration, HR decreased by 10.4 (3.7) beats/min (95% CI 2.9-17.8; p = 0.004) and MAP by 16.2 (4.4) mmHg (95% CI 7.3-25.1; p < 0.001). HR decrease was significant at 2 h and MAP decrease at 1, 2, and 3 h following dexmedetomidine administration. Dexmedetomidine administration was associated with significant reductions in opioid consumption (p < 0.001) and mRASS score (p < 0.001). SpO2 and RR remained unchanged. CONCLUSIONS: These preliminary findings suggest that intranasal dexmedetomidine reduces opioid consumption without causing respiratory depression and may be used to treat postoperative restlessness, agitation, and pain in geriatric patients. However, hemodynamic effects of dexmedetomidine may require close observation for 3 hours following administration in older adult patients.