The effect of tracheal tube size on air leak around the cuffs

Abstract

BackgroundThis randomized single-blinded, cross-over study was done to evaluate the influence of the size of tracheal tubes on air leaks around the cuffs.MethodsIn a benchtop model, the number of longitudinal folds on the cuffs was evaluated for different sizes of tracheal tubes. In an anesthetized patient study, thirty patients scheduled for elective surgery under general anesthesia were included. After induction of anesthesia, the trachea was intubated with two sizes of tracheal tubes in a random sequence: in men, internal diameter of 7.5 mm and 8.0 mm; in women, internal diameter of 7.0 mm and 7.5 mm. After tracheal intubation with each tube, air leak pressures were evaluated at intracuff pressures of 20, 25 and 30 cmH2O by auscultation. To calculate the tracheal tube resistance (R), an inspiratory pause of 20% was applied and the resulting peak airway pressure (Ppeak), plateau pressure (Ppl) and mean expiratory tidal volume (Flow) were inserted in the formula R = (Ppeak - Ppl)/Flow.ResultsMore longitudinal folds of the tracheal tube cuffs occurred in larger sized tubes compared to the smaller ones in a benchtop model. Air leakage was significantly less for the smaller tracheal tubes than for the larger ones for each gender at intracuff pressures of 20, 25 and 30 cmH2O. Tracheal tube resistances were not significantly altered by the size of tracheal tube.ConclusionsThe use of a smaller tracheal tube within an acceptable size can reduce air leakage around the cuff without significantly changing the tracheal tube resistance.

Tracheal Size Variability Is Associated With Sex

“…A thorough search of available recommendations for ETT sizing in adults revealed significant variability and lack of evidencebased practice. 22 In addition, flexible bronchoscopes with distal chip cameras (or even smaller pediatric flexible bronchoscopes) have a significantly smaller diameter (4.9 mm) compared to standard 5.7 mm adult fiberoptic bronchoscopes and can be easily passed through smaller ETTs. 15 A website targeted primarily at family practice physicians suggested 7.0 to 8.0 mm ETTs for females, and 8.0 to 8.5 mm ETTs for males, with no supporting references.…”

The Effect of Positive End-Expiratory Pressure on Air Leakage: Comparison of Cuff Designs

“…[1,3,4,[7][8][9][10] By analogy, the sealing band of TG cuff can reduce air leakage. [11] Second, peak intra-cuff pressure of TG cuff was higher than HL cuff in our results. Regardless of cuff design, increasing airway pressure is transmitted to the cuff, and then the intra-cuff pressure rises and the cuff presses itself outward into the tracheal mucosa.…”

Tracheal tube size in adults undergoing elective surgery – a narrative review

“…With this in mind, small prospective studies of patients undergoing elective surgery demonstrate no requirement for increased cuff pressure to achieve a tracheal seal when smaller tubes are used [36,51].…”