The body of the cannula (1) is formed by a straight proximal section (2) and a downwardly open distal section (3). According to the invention, the proximal section (2) has an extractable tongue (5) on the lower face thereof, which defines a tubular shape of the proximal section (2) when inserted into the body (1), facilitating the guided insertion of the endotracheal tube (20), and defines a downwardly open proximal section (2) when positioned outside the body (1), enabling the body (1) to be extracted in the vertical direction towards the outside of the mouth in relation to the endotracheal tube (20) which remains inserted in a fixed manner without axial displacement.