Flovent Inhaler

- High-volume, Low-pressure Cuffs (12)

Differences between High-Volume, Low-Pressure Designs
This study examines the performance of two different large-diameter cuff designs, both of which claim to be low pressure. While no differences are apparent at low PIPs, significant differences appear as the PIP increases (Fig 2). It is obvious from the difference in cuff inflation pressures shown in Figure 2 for the MED and HI cuff designs that all high-volume, low-pressure designs are not created equal. A reconsideration of the principles governing the self-sealing nature of these cuffs will expose their operational differences.
As airway pressure increases, tracheal diameter increases. In order to maintain tracheal occlusion at the lowest possible CT pressure, the resting cuff diameter must be greater than the tracheal diameter at the point of maximal expansion (at the PIP). As the trachea is expanded by rising airway pressure, gas within the cuff is compressed into a conical shape as described previously. A leak will develop when the gas within the cuff is compressed to the point that the diameter of the proximal end of the cuff is smaller than the diameter of the expanded trachea. At that point, providing more gas to the proximal end of the compressed cuff will abolish the leak. Unfortunately, additional cuff inflation will elevate the baseline cuff inflation pressure.

June 19, 2013 Cardiac function
Tags: airway pressure ischemic tracheal complications tracheal stenosis