Differences in residual volume above different tracheostomy tube cuffs depending on tube structure, tube tilt angle, and liquid viscosity

Abstract

Introduction: Proper management of aspirated material above the tracheostomy tube cuff is crucial to prevent complications, such as aspiration pneumonia. This study aimed to thoroughly examine the effects of aspirated liquid viscosity, suction port positioning, and tube tilt angle on residual volume above the cuff (RVAC).

Methods: Five types of tracheostomy tubes (approximately 9 mm outer diameter) were placed through a transparent cylinder with an inner diameter of 18 mm. The cuff was inflated to completely seal the interior of the cylinder. Four liquids with different viscosities were poured onto the cuff, and the liquid above the cuff was suctioned from the side port. The cylinder was angled at 90° and 20°, and each test was performed thrice to determine the average RVAC.

Results: After side-port suctioning, some liquid residue was observed on the cuff of all tracheostomy tubes. The RVAC increased with higher liquid viscosity. The tubes with a longer distance from the suction port opening to the cuff top exhibited more RVAC. Moreover, the RVAC was almost the same regardless of the cylinder angle for tubes with a suction port on the lateral side. However, tubes with backside ports showed a decreased RVAC with cylinder tilt.

Conclusions: This study underscores the persistence of residual material on cuffed tracheostomy tubes even with regular subglottic secretion drainage. This emphasizes the need for specialized tracheostomy tube development aimed at reducing post-suction RVAC. Improved designs can potentially minimize complications associated with residue accumulation.

Keywords: Cuff; Liquid viscosity; Suction port; Tracheostomy tube; Tube tilt angle; Upper cuff residual volume.

Fig. 1

Experimental setup. A Schematic image of the experimental setup, B picture of the experimental setup. The blue-dyed liquid sits above the inflated cuff before suction

Fig. 2

Evaluation methods. A Left and right sides of tracheal tube, B distance from the lower border of a suction port to the cuff top, C 90-degree cylinder angle, D 20-degree cylinder angle

Fig. 3

Structures of each tracheostomy tube. Yellow arrows indicate the dorsal suction ports. Black arrows point to the lateral suction ports

Fig. 4

Differences in the upper cuff residual volume depending on the liquid viscosity in each tracheostomy tube. Black marks indicate tubes that have more distance from the cuff top to the suction port (tubes 2 and 3)

Fig. 5

Differences in upper cuff residual volume depending on the tilt angle of tracheostomy tubes and liquid viscosity