Influence of GlideScope assisted endotracheal intubation on intraocular pressure in ophthalmic patients

Background: Traditional Macintoch laryngoscopy is known to cause a rise in intraocular pressure (IOP), tachycardia and hypertension. These changes are not desirable in patients with glaucoma and open globe injury. GlideScope is a video laryngoscope that functions independent of the line of sight, reduces upward lifting forces for glottic exposure and requires less cervical neck movement for intubation, making it less stimulating than Macintosh laryngoscopy. Aim: The aim was to assess the variations in IOP and hemodynamic changes after GlideScope assisted intubation. Materials and Methods: After approval of the local Institutional Research and Ethical Board and informed patient consent, 50 adult American Society of Anesthesiologist I and II patients with normal IOP were enrolled in a prospective, randomized study for ophthalmic surgery requiring tracheal intubation. In all patients, trachea was intubated using either GlideScope or Macintoch laryngoscope. IOP of nonoperated eye, heart rate and blood pressure were measured as baseline, 1 min after induction, 1 min and 5 min after tracheal intubation. Results: IOP was not significantly different between groups before and after anesthetic induction and 5 min after tracheal intubation (P = 0.217, 0.726, and 0.110 respectively). The only significant difference in IOP was at 1 min after intubation (P = 0.041). No significant difference noted between groups in mean arterial pressure (P = 0.899, 0.62, 0.47, 0.82 respectively) and heart rate (P = 0.21, 0.72, 0.07, 0.29, respectively) at all measurements. Conclusion: GlideScope assisted tracheal intubation shown lesser rise in IOP at 1 min after intubation in comparison to Macintoch laryngoscope, suggesting that GlideScope may be preferable to Macintosh laryngoscope