Table 2: Causes of False Results with the Oesophageal Detector Devices

• False positive result (a)

  1. Regurgitation of gas from the stomach.

  2. Oesophageal distension with gas.

  3. Oesophageal detector device not airtight.

• False negative result (b)

  1. Thick secretions occluding the ETT.

  2. Occlusion of the end of an ETT (with no Murphy eye) by the tracheal wall.

  3. Bronchial intubation.

  4. Bronchospasm.

  5. Tracheal compression.

  6. Obese patient.

  7. Chronic obstructive pulmonary disease.

ETT = endotracheal tube.

(a) ETT in oesophagus, and able to aspirate air with the syringe or the bulb refills (suggesting tracheal intubation).

(b) ETT in trachea, and unable to aspirate air with the syringe, or the bulb does not refill (suggesting oesophageal intubation).