Oropharyngeal Space in Videolaryngoscopy

• Palatopharyngeal distance [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Two laryngoscopes (one classic direct laryngoscope and one indirect videolaryngoscope) will subsequently be inserted into the patient's mouth at random order. With each laryngoscope the horizontal distance between the laryngoscope blade and mid-palatopharyngeal fold will be measured using an mm ruler.
  
  

• Difference in palatopharyngeal distance between videolaryngoscope and classic Macintosh laryngoscope [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Investigating how this space differs from the space that remains on the right side of the blade of the classic Macintosh laryngoscope and the palatopharyngeal wall in the same cohort of patients.
  
  
• Difference in palatopharyngeal distance between videolaryngoscopes [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Comparing the difference in remaining palatopharyngeal space between the different videolaryngoscopes.
  
  
• Cormack-Lehane score [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: No ]
  Registering difficulty of intubation (Cormack-Lehane score)
  
  
• Successful intubation [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Registering the number of successful intubations.
  
  
• Use of rigid stylet [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Use of rigid stylet during intubation
  
  
• Number of attempts [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Number of intubation attempts
  
  
• Time until picking up endotracheal tube [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: No ]
  Time until picking up endotracheal tube
  
  
• Epiglottic down-folding [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: No ]
  Occurrence of epiglottic down-folding
  
  
• Complications [ Time Frame: Participants will be followed during induction of anesthesia, an expected average of 10 min ] [ Designated as safety issue: Yes ]
  Any complication that occurs during intubation will be registered.
  
  

Intubation using indirect videolaryngoscopy has many advantages over classic direct laryngoscopy using the Macintosh laryngoscope. There are many different videolaryngoscopes available, and the blade differs largely between videolaryngoscopes. Different size and angles of blades may have an impact on the space available for insertion of the endotracheal tube. The space between the blade and the palatopharyngeal wall may be reduced significantly, so that there is less room in the mouth to insert an endotracheal tube. Positioning and manoeuvring of the endotracheal tube may consequently be more difficult and may traumatize the pharynx as was described in a few case reports, especially when an endotracheal tube with a rigid stylet inserted was used.