Characteristics of endotracheal tube design of different brands are related to proper endotracheal tube position in pediatrics: a descriptive study.

Background: Vocal cord markings (VCmarkings) on endotracheal tubes (ETTs) are designed to guide the proper tube placement depth. However, endobronchial intubation and cuff placement in the subglottic region still occur even when intubation depths are guided by the VCmarking. This study aimed to examine the characteristics of ETTs related to proper placement depth across different sizes and brands, including the designs of the VCmarking, cuff locations, and outer diameters (ODs).

Methods: This descriptive study examined uncuffed and cuffed tubes from seven brands with inner diameters (IDs) ranging from 3.0 to 8.5 mm that were marketed in Thailand between March and August 2022. The seven brands included: 1, Ruschelit; 2, Shiley; 3, Curity; 4, Portex; 5, Unomedical; 6, Fornia; 7, Microcuff. Mark-Tip, Mark-Cuff, and Cuff-Tip distances were measured on each tube. ODs were measured between non-cuff area and the deflated cuff level.

Results: A total of 98 tubes were included in the study (27 uncuffed tubes from four brands and 71 cuffed tubes from seven brands). VCmarkings were present in 79 (80.6%) tubes, while 37 tubes had more than one marking. For tubes of the same size, the Mark-Tip distances ranged from 10.0 to 40.3 mm, the Mark-Cuff distances varied from 1.2 to 30.4 mm, and the Cuff-Tip distances ranged from 10.7 to 21.2 mm. Minimal variation was observed in the OD at non-cuffed area, whereas the OD at the deflated cuff level added between 0.1 and 2.6 mm thickness to the OD of the non-cuffed area.

Conclusions: We observed variations in the tube characteristics which affect intubation depth (Mark-Tip, Mark-Cuff, and Cuff-Tip distances), and OD at the deflated cuff level among different brands of tubes with the same size specifications.