Dexmedetomidine reduces intraocular pressure, intubation responses and anaesthetic requirements in patients undergoing ophthalmic surgery.
We studied the effects of a single i.v. dose of dexmedetomidine, a highly selective and specific alpha 2 adrenoceptor agonist, on intraocular pressure (IOP), haemodynamic and sympathoadrenal responses to laryngoscopy and tracheal intubation, and on anaesthetic requirements in ophthalmic surgery. Thirty ASA I-II patients undergoing cataract surgery were allocated randomly to receive either dexmedetomidine 0.6 microgram kg-1 or saline placebo i.v. 10 min before induction of anaesthesia in a double-blind design. After dexmedetomidine there was a 34% (95% confidence interval (CI) 27-43%) reduction in IOP (P less than 0.001) and 62% (CI 57-68%) decrease in plasma noradrenaline concentrations (P less than 0.001). After intubation, maximum heart rate was 18% (CI 3-33%, P = 0.036) and the maximum IOP 27% (CI 11-43%, P = 0.005) less in the dexmedetomidine group compared with the patients treated with placebo. Within 10 min after intubation, maximum systolic and diastolic arterial pressures were also significantly (P = 0.013 and P = 0.020) smaller in the dexmedetomidine group. The induction dose of thiopentone was smaller (23% (CI 20-26%) P = 0.012), and the use of isoflurane or fentanyl supplements during anaesthesia was less frequent in the dexmedetomidine group. The patients premedicated with dexmedetomidine recovered faster from anaesthesia (P = 0.042). These results suggest that dexmedetomidine may be a useful anaesthetic adjunct in ophthalmic surgery.
Department of Anaesthesiology, Turku University Hospital, Finland.
M L
ML
Jaakola
T
T
Ali-Melkkilä
J
J
Kanto
A
A
Kallio
H
H
Scheinin
M
M
Scheinin
D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D000769:Anesthesia, Inhalation; D000777:Anesthetics / Q000008:administration & dosage; D002387:Cataract Extraction; D004311:Double-Blind Method; D004341:Drug Evaluation; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D007429:Intraocular Pressure / Q000187:drug effects*; D007442:Intubation, Intratracheal; D007828:Laryngoscopy; D008297:Male; D020926:Medetomidine; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood
D000316:Adrenergic alpha-Agonists; D000777:Anesthetics; D007093:Imidazoles; D020926:Medetomidine; D009638:Norepinephrine