Prospective assessment of guidelines for determining appropriate depth of endotracheal tube placement in children

Objective: To determine whether multiplying the internal diameter of the endotracheal tube (ETT) by 3 (3× ETT size) is a reliable method for determining correct depth of oral ETT placement in the pediatric population. Design: Prospective, observational. Setting: University-affiliated, 12-bed pediatric intensive care unit. Patients: Orally intubated pediatric intensive care unit patients of ≤12 yrs of age. Interventions: Demographics, ETT size, and depth of ETT placement measured from the lip were obtained. Correct placement, defined as the tip of the ETT below the thoracic inlet and ≥0.5 cm above the carina, was determined by chest radiograph. Measurements and Main Results: Suggested ETT size based on the Pediatric Advanced Life Support (PALS) age-based formula and the Broselow tape-length-based guidelines were determined. A total of 174 of 226 ETTs (77%) were correctly positioned. If practitioners utilized the 3× ETT size for the actual tubes chosen, 170 of 226 (75%) would have been accurately placed. More accurate were the 3× PALS-based ETT size (81%) and 3× Broselow-suggested ETT size (85%). The use of the Broselow ETTs to determine the depth would have led to a significantly improved ETT position (p = .003) compared with the actual ETT. Conclusion: The commonly used formula of 3× tube size for ETT depth in children results in 15-25% malpositioned tubes. Practitioners can improve the reliability of this formula by utilizing the recommended ETT size as suggested by the Brosolow tape. A more reliable method is necessary to avoid ETT malposition.