Cuffed Endotracheal Tube Size and Leakage in Pediatric Tracheal Models

Object: Cuffed endotracheal tubes are increasingly used in pediatric patients in the hope that they can reduce air leakage and tube size mismatch by just inflating the cuff. Authors compared influence of various tube sizes and different levels of cuff pressures to air leakage around the cuff, in artificial tracheal models. Methods: Six PVC cylinders of different internal diameters (ID: 8.15, 8.50, 9.70, 12.05, 14.50, and 20.00 mm) were prepared. An artificial lung connected with cylinder was ventilated with an anesthesia machine. Cuffed endotracheal tubes of different sizes (ID 3.0~8.0) were located in the cylinders and the cuff was inflated with various pressures (15, 20, 25, 30 and 35 cm H2O). Expiratory tidal volume was measured with more than 25% loss of baseline expiratory tidal volume was considered significant air leakage. Results: Tube sizes same as, or larger than ID 5.0 didn’t show significant air leakage for any trachea model, only if the inflated cuff size is larger than the cylinder ID, except ID 5.5 tube at cuff pressure 15 cm H2O and 20 cm H2O, in 12.05 mm cylinder. Tubes sizes same as or smaller than ID 4.5, which have short cuff lengths and sizes than tubes larger than, or same as ID 5.0, leaked significantly at any tracheal models, except ID 4.5 tube at cuff pressure 35 cm H2O, in 8.50 mm cylinder. Conclusion: In PVC pediatric tracheal models, tubes same as, or smaller than ID 4.5 are inferior to tubes same as, or larger than ID 5.0 in preventing air leakage, and may need a higher cuff pressure to reduce air leakage. Further clinical studies could be designed based on our results.