This study aims to asses if the application of the larynGuide™, an assistive software running on a video-laryngoscope platform guiding laryngoscopy and intubation advise correctly and reliably on the position of the tracheal tube after an intubation attempt.

Eligible patients will be prepared for intubation according to the local SOPs of the anesthesia departments with mandatory monitoring of SpO2, HR, NIBP, EtCO2.

For the anesthesia Patients will be pre-oxygenated before induction via face-mask with FiO2 = 1.0 and flow rates of 18L/min until etO2 reaches 90%. Induction of anesthesia and TI will be performed using a combination of sedative/hypnotic drugs, opioids and non-depolarizing muscle relaxant. The following medications will be mandatory as per protocol:

• Hypnotic agent (Propofol 1-4 mg/kg).
• Opioids (Fentanyl 1-3 mcg/kg, Remifentanyl 1-3 mcg/kg).
• Non-depolarizing muscle relaxant (Rocuronium 0.5-1 mg/kg). After induction of anesthesia and the administration of the muscle relaxant, bag-mask ventilation with FiO2 = 1.0 (flow rates of 18 Lmin-1) will be performed until apnea sets in. After induction all patients will be paralyzed to facilitate airway management. Neuromuscular blockade will be assessed by train-of-four monitoring. Thereafter oxygen administration, laryngoscopy and tracheal intubation are performed as usually.

Tracheal intubation performed with the aid of larynGuide™, an assistive software running on a video-laryngoscope platform guiding laryngoscopy and intubation (aiEndoscopic, Zürich, Switzerland). The larynGuide™ will be combined with the C-MAC video laryngoscope (Karl Storz, Tuttlingen, Germany) with a Macintosh nr 3 or 4 blade by a board-certified anesthesiologist. The board-certified anesthesiologist performing the intubation communicates to the research staff when he completed the intubation attempt. The anaesthesiologist in charge (board certified) checks to assess the correctness of the tube position by visual check and by attaching the patient to the ventilator and measuring the endtidal CO2 (Gold standard for detection of tube placement in anesthesia).

For the study the research staff will then - after the confirmation of the anaesthesiologist in charge of the tubes correct placement - look if the software displays a green light or the words "Bad intubation" on the monitor and document either outcome.

Inclusion Criteria:

• male or female patients ≥18 years
• ASA class I to III
• undergoing elective surgery in general anesthesia with tracheal intubation

Exclusion Criteria:

• Contraindication for intubation with C-MAC video laryngoscope (Karl Storz, Tuttlingen, Germany) with a Macintosh nr 3 or 4 blade
• Patients < 18 years
• No proper trained personnel for the device at the study site
• Expected impossible mask ventilation.
• High risk of aspiration (requiring rapid sequence induction intubation)
• Intracranial surgery
• Limited knowledge of German language or refusing informed consent

german speaking adult patients classified ASA I, II or III undergoing surgery (except intracranial surgery) in general anaesthesia with tracheal intubation without contraindication for intubation with C-mac or indication for impossible mask ventilation and high aspiration risk with given informend consent.