Dexmedetomidine sedation in painful posterior segment surgery

PURPOSE: To present a case series on the use of dexmedetomidine (Precedex) sedation in painful posterior segment surgery performed under topical anesthesia, similar to its use in cataract surgery. METHODS: A prospective review of cases that had posterior segment surgery under topical anesthesia and that needed sedation. Dexmedetomidine-loading infusion was 1 mcg/kg over 10 minutes, followed by a maintenance infusion (0.5 mcg/kg/h). RESULTS: Nine patients were operated on under topical anesthesia: two scleral buckle, five cryopexy, one scleral laceration, and one pars plana vitrectomy with very dense laser therapy in an albinotic fundus; six patients had retinal detachment. General or local anesthesia were not possible due to medical or ocular morbidities, use of anticoagulants, or the surgery plan changed intraoperatively when new pathologies were discovered. The surgeon achieved good surgical control in eight of nine cases, with one patient having ocular and bodily movements that were disturbing. Six patients had no pain, while three patients reported mild pain. No adverse effects were noted and all patients had successful surgical outcomes. Heart rate, blood pressure, and oxygen saturation were well controlled throughout the procedures. The most frequent adverse reactions of dexmedetomidine reported in the literature in less than 5% (hypotension, bradycardia, and dry mouth) were not recorded in the present study. CONCLUSION: When a surgeon has planned to do a pars plana vitrectomy under topical anesthesia and the surgical situation dictates the addition of cryopexy, scleral buckle, or intense laser retinopexy, then sedation with dexmedetomidine can help in the control of ocular pain in the majority of cases, with good intraoperative and immediate postoperative hemodynamic control with the possibility of supplemental rescue analgesia. Dexmedetomidine, a sedative analgesic, is devoid of respiratory depressant effects, and its use in posterior segment surgery under topical anesthesia is reported here for the first time.