This is a technique where you insert pressure into the ETT cuff until you no longer hear a leak, and then you take just a little pressure off so you have a minimal leak.
The goal for both techniques is to never exceed 25 cwp. The reason for this is because you want to make sure the capillary circulation to that area is not blocked off and prevent tracheal necrosis. It was also recommended that if the ETT was too small, that the cuff pressure should still never exceed 25, and whatever leak remained was tolerated. Or, better yet, the pateint should be reintubated with a larger ETT.
However, this wisdom has changed. The new recommendation (and this has been incorporated in our ventilator protocol) is for the cuff pressure never to be less than 30 cwp. The reason here is to prevent Ventilator Acquired Pneumonia (VAP) by preventing oral fluids from getting to the lungs.
No leak is tolerated. It's better to have the cuff pressure too high and to prevent a leak than too low and have a leak. Still the same is the recommendation that with every change in ventilating pressures (increases and decreases in peak pressure) the cuff pressure should be re-assessed.
Having higher cuff pressures is deemed appropriate now because due to ventilator protocols, ventilator bundles and extubation protocols. Everyone is to think extubate the moment the patient is intubated. Since the initiation of these protocols, length of time on ventilators has significantly declined. This is one of the main reasons VAP rates have also declined.
If a patient requires being on a ventilator over a week, the patient should be extubated and a tracheostomy inserted. MOV or MLT should no longer be done, and should never be charted. What should be charted with each shift is that the pressure is 30 cwp or greater.
This study from the Journal of Applied Research is one of many studies used as the basis of this change in ventilator policy. The recommendation was that cuff pressures above 29.5 was needed to keep most secretions above the trachea. Plus having cuff pressures above 29.5 significantly reduced the rate of VAP.
- Chendrasekhar, A., G.A. Timberlake, "Endotracheal cuff pressure threshold for prevention for nosocomial pneumonia," Journal of Applied Research, journalofappliedresearch.com, http://www.jrnlappliedresearch.com/articles/Vol3Iss3/Chendrasekhar.htm, accessed 8/21/2013