Chest
Volume 100, Issue 4, October 1991, Pages 1076-1081
Journal home page for Chest

High-volume, Low-pressure Cuffs: Are They Always Low Pressure?

https://doi.org/10.1378/chest.100.4.1076Get rights and content

Ischemic tracheal complications due to the ETT cuff occur in approximately 10 percent of mechanically ventilated critically ill patients despite the use of high-volume, low-pressure ETT cuffs. Using a laboratory model, we studied the effects of airway pressure on three different ETT cuff designs, including two “low pressure” designs. Positive airway pressure acted on the “low pressure” cuffs to create a “self-sealing” effect that maintained tracheal occlusion despite airway pressures that exceeded cuff inflation pressure. Increases in airway pressure caused by decreased lung compliance resulted in higher cuff inflation pressures in all three groups, with the smallest increase occurring in the design that had the longest tracheal contact length. We conclude that the current high-volume, low-pressure ETT cuff design currently used does not guarantee low cuff pressure when high airway pressures occur, and an alternative design should be developed.

Section snippets

METHODS

We studied the effects of airway pressure on the performance of current ETT cuff designs by using a laboratory model to simulate the extremes of clinically employed positive pressure mechanical ventilation, ie, under conditions of high cl with low PIP vs markedly reduced cl with high PIP.

Three ETT cuff designs, LO, MED and HI were evaluated using 7.0- and 8.0-mm ID ETTs (Fig 1). Resting cuff volumes (the performed just inflated volume) were measured using a calibrated syringe. A mechanical lung

RESULTS

Resting cuff volumes ranged from 5.2 ml for the 7.0-mm ID LO, to 20.6 mL for the 8.0-mm ID HI ETT cuff (Table 1). When cl was 100 ml/cm H2O, a PIP of approximately 15 cm H2O (11 mm Hg) was generated; reducing cl to 15 ml/cm H2O resulted in a PIP of approximately 80 cm H2O (60 mm Hg). After cuff inflation to the predetermined leak volumes we noticed that the airway pressure was transmitted to the cuff, causing intracuff pressure to rise and fall with inspiration and exhalation (Fig 3). The

DISCUSSION

This in vitro experiment utilized a plastic tracheal model specifically recommended by the American National Standards Institute for the testing of ETT cuffs designed for prolonged intubation.10 Plastic tracheal models avoid the problems of rapid deterioration of freshly excised tracheas and poor correlation between animal species.11 While our mechanical model allowed strict control of test conditions, the absolute pressures reported may not accurately reflect in vivoresults. Unlike the poorly

CONCLUSION

The confounding problem of excessive intracuff pressure, which damages the trachea but is necessary to provide a seal at high PIP, has not been resolved. We recently determined that 55 percent of a group of mechanically ventilated SICU patients required cuff inflation pressures in excess of 25 mm Hg despite the use of high-volume, low-pressure cuffs (unpublished data, E.A. Radson, T.E. Banner, M.J. Banner, et al). This observation and the report of Stauffer et al9 suggest that current cuff

REFERENCES (25)

  • Wen-HsienW et al.

    Pressure dynamics of endotracheal and tracheostomy cuffs.

    Crit Care Med

    (1973)
  • CarrollR et al.

    Intratracheal cuffs: performance characteristics.

    Anesthesiology

    (1969)
  • Cited by (0)

    From the University of Florida College of Medicine, Gainesville.

    View full text