The clinical importance of airway management has gained prominence in the last decade in most scientific societies with the aim of improving the standard of care.

The WHO has focused guidelines for "Safety in Surgery", which attempt to encompass all methods that predict and recognise airway management risk and should be applied by the surgical team, and has therefore created and implemented a surgical checklist that can be useful in reducing the risk of unidentified difficulties.

The same suggestion has been included in the Helsinki Declaration on Patient Safety in Anaesthesiology, signed by most European entities in cooperation with the European Society of Anaesthesiology (ESA), the European Board of Anaesthesiology (EBA-UEMS), and the World Federation of Societies of Anaesthesiology (WFA).

Confirmation of correct endotracheal tube (ET) placement is a crucial step in airway management, as unrecognised oesophageal intubation can have catastrophic consequences. Numerous methods are used to verify correct ET placement, including visual confirmation of tube passage through the vocal cords during laryngoscopy, chest wall expansion during ventilation, visualisation of the tracheal rings and carina using a flexible bronchoscope, auscultation, capnometry, capnography and chest radiography. These techniques vary in their degree of precision. Although capnography is considered the gold standard for confirming tracheal intubation, it has some important limitations.

In recent years, ultrasonography has been introduced as the fifth pillar of the physical examination of the patient: inspection, palpation, percussion, auscultation and insonation. For airway assessment and management, Point-of-Care UltraSound (PoCUS) has been incorporated into routine clinical practice, answering open diagnostic questions, aiding in differential diagnosis and guiding procedures.

Thus, investigators propose a simple, quick and easy-to-learn approach for the interpretation of ultrasound imaging findings during airway management.

The first step of the algorithm is to locate the oesophagus by asking the patient to swallow. The ultrasound transducer is placed transversely on the anterior surface of the neck at the paratracheal level (usually located on the left side), 1-2 cm above the sternal notch or jugulum. In this image, the trachea is shown as a hyperechoic, curvilinear image (air-mucosa interface), showing a posterior reverberation artefact called a comet tail. During the intubation technique, this ultrasound window allows the physician to observe the real-time passage of the tube into the trachea, confirming correct tracheal intubation only if a single air-mucosa interface with its comet tail is maintained. This can then be verified by capnography (if available) or by lung sliding.

Inclusion Criteria:

Patients (male or female) ASA I-III, aged between 18 and 90 years, undergoing scheduled and/or emergency surgery requiring orotracheal intubation. Informed consent form must be signed authorising inclusion in the study.

Exclusion Criteria:

A.- Cervical tumours, goitre or patients who have required cervical radiotherapy.

B.- Abnormalities leading to alterations of the anatomy such as facial/cervical fractures.

C.- Those who cannot give their consent.

Patients (male or female) ASA I-III, aged between 18 and 90 years, undergoing scheduled and/or emergency surgery requiring orotracheal intubation. Informed consent form must be signed authorising inclusion in the study.

It is not neccessary to share any data.