The primary end point of this study is the feasibility of intubation. The secondary end-points are the success to intubate in the first attempt, the intubation time, the Cormack and Lehane score view, the comparison of the intubation difficulty scale (IDS) score and the need for maneuvers to aid the endotracheal intubation comparing Imago V-Blade ® and Glidescope®.

Patients admit to the operation rooms of University of Naples "Federico II" and requiring endotracheal intubation for general anesthesia will be consecutively screened for the presence of predicted difficult airway according Italian guideline. According to this guideline, the presence of one or more of the following parameters may be considered highly predictive of difficult intubation: Mallampati class 3-4, inter-incisor distance < 30 mm, mental-thyroidal distance < 60 mm, large prominence of superior incisors above inferior incisors uncorrectable with jaw-thrust, reduced head and neck motility, and reduced mental-jugular distance. Patients matching more then 1 of the previous criteria stated by Italian guideline will be included in this case controlled study. Patients 1) without criteria for predicted difficult airway; 2) those requiring emergency surgery; 3) aged < 18 years; or 4) declined consent to participate, will be excluded from this study.The primary end-point was the comparison of the intubation difficulty scale (IDS) score. The secondary end-points were the learning curve, the intubation time, the Cormack and Lehane score view, and the need for maneuvers to aid the endotracheal intubation comparing different videolaryngoscopes available in our department. Two anesthesiologists with 10 years of experience in conventional endotracheal intubation and trained for video assisted intubation will perform the maneuvers.

Inclusion Criteria:

• Age>18 years
• Mallampati class 3-4
• inter-incisor distance < 30 mm
• mental-thyroidal distance < 60 mm
• large prominence of superior incisors above inferior incisors uncorrectable with jaw-thrust -reduced head and neck motility
• reduced mental-jugular distance.

Exclusion Criteria:

• < 1 criteria for predicted difficult airway
• emergency surgery
• age < 18 years
• declined consent to participate