Remifentanil target-controlled infusion with intranasal dexmedetomidine for vitreoretinal procedures: a randomized controlled trial

AimTo evaluate the consumption of remifentanil (as a primary end-point), analgesia, sedation, hemodynamics, respiratory effects, and surgeon and patient satisfaction (as a secondary end-point) with dexmedetomidine sedation compared with those of remifentanil sedation in patients undergoing vitreoretinal surgery.MethodsPatients subjected to retinal ophthalmic surgical procedures were randomized to one of two intraoperative sedation groups: one group (n = 21) received intranasal dexmedetomidine plus intravenous remifentanil (DEX-REMI group), and the other group (n = 19) received intravenous remifentanil only (REM group). The treatment was placebo-controlled. The sedation level was controlled according to the bispectral index, with target values between 80%-90%. Patient levels of comfort, sedation, and pain were documented. The number of intraoperative complications and the level of satisfaction were assessed. Remifentanil consumption and hemodynamic parameters were also included in the statistical analysis.ResultsThe level of remifentanil consumption was significantly lower in the DEX-REMI group, but combination sedation improved the surgeon''s, anesthesiologist''s, and patients'' satisfaction scores. Importantly, the number of complications was zero in the DEX-REMI group, while eight cases of complications were noted in the REM group. The DEX-REMI group showed lower mean minimal arterial pressure, but it was still in the normotensive range.ConclusionsFor patients undergoing ophthalmic procedures, sedation with a combination of intranasal dexmedetomidine and an intravenous infusion of remifentanil provides lower remifentanil consumption, better satisfaction scores, and a lower complication rate than sedation with a remifentanil infusion alone.Clinical trial number{"type":"clinical-trial","attrs":{"text":"NCT 03251222","term_id":"NCT03251222"}}NCT 03251222

Conscious sedation is an established anesthetic method of choice in patients undergoing short ophthalmic procedures and has been used successfully for many years. In Slovenia, there is also a published protocol in use for such cases (1).Intravenous (i.v.) remifentanil is used for analgesic and sedative purposes. It is a short-acting opioid analgesic with partial anxiolytic action that has been thoroughly studied in obstetric analgesia (2).The fine intra-ocular endoscopic technique is implemented in vitrectomies. Surgical instruments are inserted into the vitreous humor through the sclera by a surgeon. Patient cooperation is crucial during the procedure, meaning the level of sedation should not be too deep. Otherwise, sudden eye movements could potentially result in eye injury (3). For many ophthalmic surgeons, local anesthesia (LA) has become preferred over general anesthesia (GA) because of quicker patient rehabilitation and avoidance of possible complications from GA (4). Several methods of LA have been described for vitreoretinal cases, including retrobulbar, peribulbar, sub-Tenon’s, and even topical anesthesia (5). Many drugs have been used for sedation during eye surgery, such as propofol, benzodiazepines, and opioids, and there is a relative risk of oversedation, disorientation, and confusion, in addition to an increased risk of respiratory depression and oxygen desaturation (5,6). All of these adverse effects can hamper patient cooperation during surgery and make these agents less than ideal for intraoperative management of sedation. As a result, sedatives and anxiolytics with unpredictable dose requirements, such as propofol and midazolam, are not optimal for such procedures.In contrast, dexmedetomidine is a highly selective alpha-2-adrenoreceptor agonist with both sedative and analgesic properties and is not associated with respiratory depressant effects. Dexmedetomidine has been studied for its sedation- and analgesia-sparing properties in intensive care and surgical settings (eg, neurosurgery, maxillofacial surgery, ENT surgery) but not in vitreoretinal surgery (7-9).Dexmedetomidine is mainly administered intravenously. Although intranasal (i.n.) dexmedetomidine is still used off-label, recently an increasing consensus has emerged for its different uses, namely, in non-painful diagnostic procedures, in painful procedures, and in surgical premedication. Some studies have been published regarding this form of use in the pediatric population (10-12). However, at present, there is no consensus regarding indications, dosage, and timing for administration. Available pediatric evidence confirms the efficacy and safety of dexmedetomidine for i.n. administration. The reported dose for pediatric procedures performed under sedation ranges from 2.5 to 4 μg/kg i.n. Onset of action is expected to be slower (25-30-minute) with low doses (1-2 μg/kg) and faster (16.7-28-minute) with higher doses (2.5-3 μg/kg), while offset time is similar in both – 85-minute in average; range 55-100 minutes (13).The aim of our study was to evaluate the consumption of remifentanil (as a primary end-point), analgesia, sedation, hemodynamics, respiratory effects, and surgeon''s and patients'' satisfaction (as a secondary end-point) with dexmedetomidine sedation compared with those of remifentanil sedation in patients undergoing vitreoretinal surgery. We conducted an applied research study that produced objective indicators, showing which type of sedation was more comfortable for patients and more effective in terms of achieving the desired sedation and reducing pain during vitreoretinal procedures with fewer side effects.