title: Dexmedetomidine as intramuscular premedication in outpatient cataract surgery. A placebo-controlled dose-ranging study.
abstract: Alpha 2 agonists have been shown to decrease intra-ocular pressure in ophthalmic surgery. We studied the effects of dexmedetomidine, a new alpha 2 agonist, on intra-ocular pressure, haemodynamic parameters, sedation, anxiolysis and dryness of mouth in 35 (ASA physical status 1-3) patients undergoing day-case cataract surgery under peri-ocular anaesthesia. Five different doses of dexmedetomidine (0.25, 0.5, 0.75, 1.0 and 1.5 micrograms.kg-1) were used in this double-blind, randomised and placebo-controlled study. The trial drug was administered into the deltoid muscle 60 min before surgery. The 1.0 micrograms.kg-1 dose of dexmedetomidine produced a 32% reduction of intra-ocular pressure (p = 0.002). This dose induced moderate sedation, but was not associated with significant haemodynamic changes. A significant decrease in heart rate and systolic blood pressure was seen only with the highest dose of dexmedetomidine. Our results suggest that dexmedetomidine 1.0 micrograms.kg-1 produces sedation and a reduction of intra-ocular pressure with minimal haemodynamic side effects when given intramuscularly as premedication before cataract surgery under regional anaesthesia.
authors.affiliation: Department of Anaesthesiology, Turku University Hospital, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Virkkilä
authors.forename: T
authors.initials: T
authors.lastname: Ali-Melkkilä
authors.forename: J
authors.initials: J
authors.lastname: Kanto
authors.forename: J
authors.initials: J
authors.lastname: Turunen
authors.forename: H
authors.initials: H
authors.lastname: Scheinin
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000556:Ambulatory Surgical Procedures; D001794:Blood Pressure / Q000187:drug effects; D002387:Cataract Extraction; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives; D007093:Imidazoles / Q000627:therapeutic use*; D007273:Injections, Intramuscular; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D020926:Medetomidine; D008875:Middle Aged; D010919:Placebos; D011229:Preanesthetic Medication
chemical_list: D000316:Adrenergic alpha-Agonists; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D010919:Placebos; D020926:Medetomidine