Intravenous Versus Peribulbar Dexmedetomidine for Strabismus Surgery in Adults

A Comparative Study of Intravenous Versus Peribulbar Administration of Dexmedetomidine for Strabismus Surgery in Adults

Using various adjuvants has become a trend in regional anesthesia practice to improve the quality of anesthesia and prolong postoperative analgesia. Dexmedetomidine, an alpha-2 agonist has been proposed as a safe and effective adjunct capable of extending the duration of the single-shot block

Strabismus (misalignment of the eye/eyes) results from an imbalance in extraocular muscle function. Consequently, two different images, one from each eye, are transmitted to the brain, resulting in loss of visual depth. In adults, cosmetic appearance is the main issue but sudden occurrence of strabismus may cause diplopia because the brain cannot suppress the overlapping images. The goal of strabismus surgery is to align the eyes, reduce diplopia, and restore binocular vision Ophthalmic regional block can be used as the primary anesthetic technique for strabismus surgery. The advantages of ophthalmic regional blockade include a reduced incidence of oculocardiac reflex (OCR) and emergence agitation, postoperative analgesia, and decreased postoperative nausea and vomiting (PONV). Using various adjuvants has become a trend in regional anesthesia practice to improve the quality of anesthesia and prolong postoperative analgesia. Dexmedetomidine, an alpha-2 agonist has been proposed as a safe and effective adjunct capable of extending the duration of the single-shot block. Perineural dexmedetomidine when added to bupivacaine has shown to potentiate its effects, providing a better quality of anesthesia and postoperative analgesia, Intravenous (I.V.) dexmedetomidine, when used during regional anesthesia, has shown to prolong sensory and motor blockade in addition to sedation and postoperative analgesia. No previous studies where different routes of dexmedetomidine have been compared in adult strabismus surgery.

Peribulbar block will done using mixture of Lidocaine 2%, bupivacaine 0.5% plus 0.5 μg / kg dexmedetomidine perineurally (30 patients).

The peribulbar block will be done using a mixture of Lidocaine 2%, bupivacaine 0.5% plus 0.5 μg / kg dexmedetomidine in 50 mL of normal saline administered as an infusion over 10 min and is given 10 min before the start of the peribulbar block(30 patients).

to compare perineural (peribulbar) dexmedetomidine versus intravenous (I.V.) dexmedetomidine when used as an adjuvant with local anesthesia in adult strabismus surgery.

Time lapse between complete injection of local anesthesia till abolishment of sensation using goose soaked with iced normal saline / Corneal reflex

Time lapse between abolishment of sensation using goose soaked with iced normal saline / corneal reflex and the commencement of postoperative pain

Time lapse between complete injection of local anesthesia till complete abolishment of ocular motility (akinesia)

Time lapse between complete abolishment of ocular motility (akinesia) till fully returned of ocular motility and disappearance of diplopia

Inclusion Criteria: The patients planned to perform a unilateral strabismus surgery Age: 20-60 years American Society of Anesthesiologists class I and II Exclusion Criteria: patients under the age of 20 Patients have systemic or bleeding disorders Patients with ocular or neurological problems, mental retardation, deafness, or dementia patients who disincline to participate in the study will be excluded from the study