Endotracheal intubation is a frequent procedure in the operating room but optimal Macintosh blade size remains unknown to date.

Endotracheal intubation is an extremely frequent procedure in the operating room, in intensive care units and in emergency medicine (in- or out-of-hospital). Apart from special cases of foreseen difficult programmed intubation, direct laryngoscopy remains the most frequently used technique. It requires the use of a handle (short or long), which serves as a light source on which is adapted a Macintosh curved blade, metallic or plastic, single or multiple use. The choice of blade size is based on the experience of the physician. Most often, in adult settings, size 3 or 4 blades are used. The very spartan literature on the subject and the current recommendations do not provide any information on the choice of blade size. Our team (and others) recently concluded that intubation first attempt rates in intensive care units or emergency settings were improved when using shorter Macintosh blade size No3 vs 4 (Godet et al. Intensive Care Medicine 2022 and Landefeld et al. Critical Care Explorations 2023). We therefore wish to evaluate these practices in terms of success of the first laryngoscopy, Cormack-Lehane and POGO (percentage of glottic opening visualized) scores, the need to use an alternative technique or a second operator in operative rooms. The results will be analyzed with regard as a function and experience of the person performing the laryngoscopy, as well as the setting (urgent or scheduled). These data are usually collected during the performance of an endotracheal intubation in a nationwide fashion in French operative rooms.

Inclusion Criteria:

• Patients must be admitted in a participating operative room and require mechanical ventilation through an orotracheal tube.
• Adult (age ≥ 18 years)
• Subjects must be covered by public health insurance
• Written informed consent from the patient or proxy (if present) before inclusion or once possible when patient has been included in a context of emergency.

Exclusion Criteria:

• Anticipated difficult intubation requiring videolaryngoscopy or other technic in first place
• Nasotracheal intubation
• Refusal of study participation or to pursue the study by the patient
• Absence of coverage by the French statutory healthcare insurance system
• Protected person

Any patient requiring orotracheal intubation with direct laryngoscopy in first place

Data available upon reasonable request and satisfactory presented analysis plan. Authorship will include principal investigator (last author).

Data available after study completion and publication