Introduction

Misplacement of a tracheal tube is a common complication. The tube may pass into the oesophagus or a main bronchus; this may occur at initial placement or the tube may migrate to one of these positions after movement of the patient. Oesophageal intubation is a preventable complication, which is lethal if unrecognized and which every anaesthetist must remain constantly on guard against.

Reasons for confirming tracheal intubation

The prompt recognition of misplacement is important because of the following:

1. • If not corrected, oesophageal placement will lead to:

2. – insufflation of the stomach when attempting to ventilate the lungs (in children this can lead to bradycardia and in all ages it increases the risk of regurgitation of stomach contents);

3. – hypoxia, brain damage and/or death.

4. • If not corrected, bronchial placement may lead to:

5. – hypoxaemia from shunting of blood;

6. – lung or lobar collapse;

7. – increased airway pressure and possible barotrauma/volutrauma.

8. • Consequently it is vital to:

9. – differentiate between a tube which has passed through the vocal cords from one which is in the oesophagus;

10. – determine that a tube through the cords is in the trachea and not in a main bronchus.

A variety of tests has been devised to do each of these. The tests reviewed here do not comprise a comprehensive list, but are commonly used, reliable or both. The reliability is evaluated according to estimates of the frequencies of false positives (related to specificity) and negatives (related to sensitivity) (Table 9.1). When reading publications on this topic it is important to be clear as to whether the authors are describing their results in terms of the ability of the test to identify tracheal or oesophageal placement.