Originally published on May 30, 2010
P.T. asks, “What is the purpose of downsizing?”
Answer: The purpose of downsizing is to allow the patient to do more breathing around the tube, rather than through the tube. When the initial problem that initiated placement of the trach is resolved, downsizing may begin. For example, when the tube was placed because of prolonged mechanical ventilation, downsizing can begin as soon as the patient has been weaned from the ventilator.
Downsizing should begin with cuff deflation, which allows admixture of room air, lowering overall FiO2. So downsizing should not begin until the patient is hemodynamically stable and can tolerate cuff deflation.
When the patient is able to tolerate cuff deflation, the tube can be changed to one with a smaller outer diameter. Capping can begin at that time (and never with a standard cuffed tube).
The end result of downsizing is usually with the overall goal of decannulation; however, the tube may need to be downsized in order to allow enough air around the tube to reach the vocal cords for phonation. See the Downsizing Algorithm in Chapter 11 for a step-wise procedure on downsizing.