This study aims to evaluate the clinical performance, quality of larynx visualization and difficulty of videolaryngoscopic intubation in patients with a reduced mouth opening (1.0 to 3.0 cm) utilizing the latest generation of GlideScopeTM Spectrum low profile laryngoscopy system.

Reduced mouth opening in adults has been proven an important risk factor for difficult endotracheal intubation utilizing both direct and indirect laryngoscopy techniques, and a major reason for anesthesia-related adverse events. Over the past two decades, videolaryngoscopy has evolved to be the primary indirect laryngoscopy technique in a difficult endotracheal intubation setting. The possibility for optimal visualization of the laryngeal structures renders this method particularly helpful in patients with limited mouth opening. Especially videolaryngoscopy with acute-angle blades has been proposed to be favorable over conventional direct laryngoscopy in this setting. However, previous research has shown that a mouth opening of approximately 2.0 - 3.0 cm represents an independent risk factor and a possible critical lower limit for safe videolaryngoscopic intubation.

The latest generation of GlideScopeTM Spectrum blades may provide sufficient intubation conditions even in patients with a maximum mouth opening below 3.0 cm.

Our research group aims to evaluate the clinical performance, quality of larynx visualization and severity of videolaryngoscopic intubation the GlideScopeTM Spectrum system in patients with a small mouth opening.

Inclusion Criteria:

• Patients scheduled for non-cardiac surgery
• Required general anesthesia and endotracheal intubation
• Mouth opening between 1.0 and 3.0 cm (any reason) recognized during preoperative assessment
• Written consent provided

Exclusion Criteria:

• Pregnant or breastfeeding women
• Confirmed indication for awake fiberoptic intubation, especially due to enoral and pharyngeal tumors, abscesses or other obstructive lesions
• Endotracheal intubation planned without deep general anesthesia or without neuromuscular blockade (e.g. awake videolaryngoscopy)
• Qualification for rapid sequence anesthesia induction due to risk of pulmonary aspiration
• Loose teeth

All patients scheduled for non-cardiac surgery under general anesthesia with a need for endotracheal intubation presenting at the Anesthesiology Preassessment Clinic of the Hamburg University Hospital with a mouth opening between 1.0 and 3.0 cm within the recruiting period.