Effects of Videolaryngoscope on Intraocular Pressure

The Comparison of the Effects of McGrath Video Laryngoscope and the Macintosh Laryngoscope on Intraocular Pressure: A Randomized Trial

This study is designed to compare the effects of the McGrath Series 5 video laryngoscope and Macintosh laryngoscope on intraocular pressure during laryngoscopy.

The stability of the intraocular pressure plays an important role during ophthalmic surgery. The systemic blood pressure, aqueous humor dynamics, choroidal blood volume, central venous pressure, extra-ocular muscle tone, and also conventional laryngoscopy affect the intraocular pressure.It was shown that the new devices for laryngoscopy, such as video laryngoscopes provide minimal hemodynamic changes when compared to direct laryngoscopes. However there is no current data about the effects of the intubation with McGrath videolaryngoscope on intraocular pressure. The main objective of this study to compare the effects of the McGrath Series 5 video laryngoscope and Macintosh laryngoscope on intraocular pressure during laryngoscopy.

Inclusion Criteria:

• American society of anesthesiologist physical status I
• Non-ophthalmic elective surgery under general anesthesia

Exclusion Criteria:

• A history of pre-existing glaucoma or previous intraocular surgery
• Thyromental distance below 6cm
• Maximum mouth opening below 3cm
• Mallampati score of III or IV
• Pre-anesthetic intraocular pressure above 20 mmHg
• Number of intubation attempts more than 2
• Obstetric or laparoscopic surgery