Nasotracheal intubation.

Abstract

Nasotracheal intubation is a skill greatly appreciated by anaesthetists and surgeons in head and neck specialities and the recent review (Hall & Shutt. Anaesthesia 2003; 58: 249–6) was timely and interesting. Nasotracheal intubation can protect teeth as mentioned in the review, but is under-used for that purpose in general surgical and many other operations where orotracheal intubation is usually performed. Dental damage is one of the commonest negligence claims against anaesthetists. Cases tend to be settled out of court and the settlements represent 1% of negligence claims [1]. However, some damage could be avoided if nasotracheal rather then orotracheal intubation is used. Nasotracheal placement eliminates biting on the tube during recovery, and the tube can be withdrawn partially and used as a nasopharyngeal airway. This does not usually lead to nasal bleeds as the presence of the tube tamponades potential bleeding points in the nose. Bleeding may occasionally occur after the full removal of the tube, but protective reflexes should be present at this stage. The use of nasotracheal intubation for protection of teeth and dental prosthetic work is justified and under-used. Contraindications to nasotracheal intubation were clearly stated by the authors, but operations with a potentially large peri-operative blood loss where a coagulopathy may develop need special consideration with this extended indication. The era of fibreoptic laryngoscopy has changed difficult intubation techniques and blind nasal intubation is becoming a rare event, and a technique of the past. Bleeding, dislodging of nasal polyps, etc., and the possibility of aspiration, or even the penetration of the retropharyngeal tissues by the nasotracheal tube are strong arguments against its use. These concerns can be alleviated, and teeth and dental prosthetic work further protected with a modification of the blind nasotracheal intubation technique. Inspecting the tip of the tracheal tube after passage through the nose and nasopharynx is usually (unless opening of the mouth is limited) easily achieved using the light source of the laryngoscope. Dental damage tends to be caused by attempts to visualise the larynx, not the tip of the tube in the oropharynx. After inspection of the tip of the tube, it can be advanced gently into the trachea. Nasotracheal intubation is greatly facilitated if the patient's head is placed on a pillow with some extension of the atlanto-occipital joint – a position described as ‘sniffing the morning air’. The tip of the tube can be inspected in the oropharynx, then with the teeth occluded, the nasotracheal tube is advanced in the optimal anterior–posterior plane. It often deviates laterally (right in the case of right nostril and left if the left nostril is used) and indentation in the neck can be noticed. The tube then needs to be withdrawn to the upper part of the oropharynx and redirected after a rotation by about 30° or more. With occlusion maintained by an assistant, the larynx can be gently moved by the anaesthetist's hand laterally to meet the advancing tube. As this part of the procedure is blind, the use of force to advance the nasotracheal tube should be avoided. The number of attempts at blind intubation should be limited. If not successful, a laryngoscope may be used and the tube advanced under direct vision, while additional attention is paid to the teeth, which are now at increased risk. Direct observation of the anatomy in relation to the advance of the nasotracheal tube at this point increases experience for the future. Alternatively, the patient may be re-positioned and oxygenated for further attempts at a blind technique if dental protection is required. The technique described above applies to paralysed adult patients. It is our aim to intubate patients before additional oxygenation is needed. The success of blind intubation within this time constraint is about 70% in our hands.