Ideal endotracheal tube placement by referencing measurements on the tube

The ideal position of the endotracheal tube (ETT) within the trachea is 5 +/- 2 cm from the carina with the head and neck in neutral position (Goodman's criteria). We assessed the possibility of achieving ideal placement of ETTs in our population by positioning them at reference marks of 23 cm in men and 21 cm in women. From January 1995 to April 1995, 105 intubated patients in the Medical Intensive Care Unit, Singapore General Hospital were studied. The mean distance of the ETT tip from the carina was 4.02 cm +/- 3.90. The ETT tip was < 3 cm from the carina in 30 cases (28.6%) with one case resulting in endobronchial intubation. These 30 patients were significantly shorter in height when compared to the rest of the study population (P = 0.01). Five cases (4.8%) had ETT tip > 7 cm from the carina. Adopting the above-mentioned reference marks did not result in ideal positioning of ETTs in a significant proportion of cases (33.4%). We postulate that this is because our Asian population is generally shorter than those in previous studies which had achieved ideal ETT positioning using similar reference marks.