Dexmedetomidine as an additive to local anesthetics compared with intravenous dexmedetomidine in peribulbar block for cataract surgery

Abstract

Background:No studies compared parenteral dexmedetomidine with its use as an adjuvant to ophthalmic block. We compared between adding dexmedetomidine to bupivacaine in peribulbar block and intravenous (IV) dexmedetomidine during peribulbar block for cataract surgery.Materials and Methods:A prospective, randomized, double-blind study on 90 patients for cataract surgery under peribulbar anesthesia. Study included three groups; all patients received 10 ml of peribulbar anesthesia and IV infusion of drugs as follows: Group I: Received a mixture of bupivacaine 0.5% (4.5 ml) + lidocaine 2% (4.5 ml) + normal saline (1 ml) + 150 IU hyaluronidase + IV infusion of normal saline, Group II: Received mixture of bupivacaine 0.5% (4.5 ml) + lidocaine 2% (4.5 ml) + dexmedetomidine 50 μg (1 ml) +150 IU hyaluronidase + IV infusion of normal saline and Group III: Received mixture of bupivacaine 0.5% (4.5 ml) + lidocaine 2% (4.5 ml) + normal saline (1 ml) +150 IU hyaluronidase + IV dexmedetomidine 1 μg/kg over 10 min; followed by 0.4 μg/kg/h IV infusion. We recorded onset, duration of block, Ramsay Sedation Score, intra-ocular pressure (IOP), hemodynamics, and adverse effects.Results:There was a significant decrease in the onset of action and increase in the duration of block in Group II as compared with the Group I and Group III. Mean Ramsay Sedation Score was higher in Group III. The IOP showed a significant decrease in Group II and Group III 10 min after injection (P < 0.01). Heart rate showed a significant decrease in Group III in comparison with the two other groups (P < 0.05). Only two patients in Group III developed bradycardia.Conclusion:Dexmedetomidine as an additive shortens onset time, prolong block durations and significantly decreases the IOP with minimal side effects. IV dexmedetomidine, in addition, produces intra-operative sedation with hemodynamic stability.

Dexamethasone compared to dexmedetomidine as an adjuvant to local anesthetic mixture in peribulbar block for vitreoretinal surgery. A prospective randomized study

“…It may also facilitate drainage of aqueous humor by reducing the sympathetic mediated vasomotor tone of the drainage system of the eye. [ 17 18 ] Our results were similar to those obtained by Channabasappa et al . [ 19 ] who reported that a combination of bupivacaine and lidocaine with dexmedetomidine in peribulbar anesthesia helped to decrease the IOP significantly.…”

“…[ 17 ] Alpha 2-agonists acts peripherally by reducing the discharge of norepinephrine and by inhibition of nerve fiber action potential while their central analgesic effect is produced at the level of the dorsal root neuron in pain pathway as well as at the locus coeruleus by preventing the release of substance P and by activation of α2-receptors, respectively. [ 18 ]…”

Dexmedetomidine as an Additive to Local Anesthesia for Decreasing Intraocular Pressure in Glaucoma Surgery: A Randomized Trial

“…This may be explained by the patients' co-morbidities, such as hypertension that was treated with heart rate-controlling medications. Dexmedetomidine has been tested in many studies alone or as an adjuvant to bupivacaine in the peribulbar block (3,7,10,11). This combination aims to prolong the block duration to hasten the onset, decrease intraocular pressure, and look for its sedative effects.…”

Optimal dose of dexmedetomidine retrobulbar anesthesia during phacoemulsification cataract surgery

“…who showed reduction in the IOP after both local and IV dexmedetomidine during their study on cataract surgery by peribulbar block. [ 13 ] The dexmedetomidine effect on the IOP may be due to decrease production of aqueous humor secondary to its direct vasoconstrictive effect on the afferent blood vessels of the ciliary body Furthermore, because of its reducing sympathetic output with of vasomotor tone reduction of ocular muscle, it could also facilitate the drainage of aqueous humor. [ 14 ] Furthermore, Virkkilä et al .…”