Comparing Hemodynamic Changes for Intubation With Shikani Intubating Stylet and Macintosh Laryngoscope

Because of its simplicity of function and reliability, direct laryngoscopy it is routinely used for endotracheal intubation during general anesthesia. However, direct laryngoscopy is fraught with concerns for cardiovascular stimulation during induction of general anesthesia. This can be attributed to the placement of the laryngoscope blade into the vallecula and then applying force in an upward direction to expose the glottic opening. The average force necessary for visualization of the glottic opening is approximately 5.4kg. This can lead to significant pressor responses and tachycardia though stimuli to supraglottic region.

An alternative airway management device is the Shikani optical stylet (SOS). It is an effective, safe and reusable intubation device that has been shown to be effective in cases of difficult intubation. It consists of a fiberoptic bundle within a J - shaped malleable stainless steel sheath. At the proximal end of the sheath is an eyepiece with an attachment to a light source. An adjustable "tube stop" firmly affixes the endotracheal tube to the stylet, and has a port to be able to deliver oxygen. (4) The operator inserts the tip of the stylet with the loaded endotracheal tube into the patient's oropharynx and under direct visualization through the eyepiece, is able to visualize the vocal cords. Because the end of the stylet is at the end of the endotracheal tube, it can be directly visualized to be entering trachea past the vocal cords.

The investigators hypothesize that endotracheal intubation performed by the aid of SOS by minimizing oropharyngolaryngeal stimulation will result in fewer hemodynamic changes in patients with normal airways as compared with the MacIntosh laryngoscope.

Inclusion Criteria:

• 18 - 75 years, ASA I and II, normotensive, Mallampati class: I and II, thyromental distance > than 6.5 cm, interincisor distance > than 3 cm, BMI < 35 Kg/m2

Exclusion Criteria:

• Exclusion criteria: pregnant patients, known or expected difficult airway, gastroesophageal reflux, esophageal pathology, pulmonary pathology, cardiovascular pathology.