Lightwand intubation does not reduce the increase in intraocular pressure associated with tracheal intubation

Objective: To evaluate the changes in hemodynamic variables and intraocular pressure (IOP) after tracheal intubation using either lightwand or direct- vision, laryngoscopy techniques Design: Prospective, randomized study. Setting: Inpatient anesthesia at a University Anesthesia Department. Patients: 50 normotensive, ASA physical status I and II patients, without o cular or cardiovascular diseases, and with a Mallampati score no greater th an 2. Interventions: After intravenous (IV) midazolam premedication (0.05 mg . kg (-1)) general anesthesia was induced with fentanyl (1 mu g . g(-1)) and thi opental sodium (5 mg . g(-1)) followed by vecuronium bromide (0.1 mg . g(-1 )), then patients were randomly allocated to receive either the lightwand ( Trachlight, n = 25) or direct-vision laryngoscopy (Laryngoscopy, n = 25) in tubating techniques. General anesthesia was maintained with 1% isoflurane a nd 60% nitrous oxide in oxygen mixture for 5 minutes. Measurements and Main Results: Baseline hemodynamic variables were recorded 10 minutes after IV premedication, and then every minute after tracheal in tubation. Intraocular pressure measurements were Performed by means of a co mputerized indentation tonometer after general anesthesia induction and the n I and 5 minutes after tracheal intubation. In both groups, mean arterial blood pressure and heart rate increased from baseline, without differences between the two groups One minute after intubation, IOP increased in both g roups: the mean percentage increase was 32% in the Laryngoscopy group and 1 6% in the Trachlight group. However; this difference was not statistically significant Five minutes after intubation, IOP decreased to baseline values in both groups. Conclusion: We conclude that in healthy patients without ocular disease, us ing a lightwand intubating technique does not reduce the hemodynamic respon ses and increase in IOP associated with tracheal intubation as compared wit h conventional direct-vision laryngoscopy. (C) 1999 by Elsevier: Science.