Tuesday March 28, 2006
Cuff leak test - to anticipate post-extubation stridor
There are atleast 3 common ways to do cuff leak test to anticipate postextubation stridor but none has been really tested in a big scientific randomized trial. And literature is full of conflicting studies.
1. Bedside crude method: Deflate the cuff, +/- occlude the ETT and put your hand at mouth to feel exhaled air. (isn't it brutal?)
2. Record the difference between the inspiratory tidal volume and the expiratory tidal volume while the cuff around the endotracheal tube was deflated. (Average of any three values on six consecutive breaths). Cuff leak less than 110 mL is more associated with postextubation stridor.
3. Record the difference in exhaled tidal volume from before to after endotracheal tube cuff deflation. Divide this number by the exhaled tidal volume before cuff deflation. Your answer is 'percent cuff leak'. Patients with a cuff leak of less than 10% are at risk for stridor or reintubation.
Some other methods like laryngeal ultrasound has also been described in literature. Also, experts recommend to test the ability to expel secretions with an effective cough. Be aware, a low value for cuff leak may actually be due to encrusted secretions around the tube rather than to a narrowed upper airway. Reintubation equipment (including tracheostomy equipment) should be readily available during extubation and immediate postextubation period.
Related previous pearl: Spontaneous Breathing Trial (SBT)
References: Click to get abstract/article
1. Association between reduced cuff leak volume and postextubation stridor - Chest, Vol 110, 1035-1040
2. Measurement of endotracheal tube cuff leak to predict postextubation stridor and need for reintubation - J Am Coll Surg. 2000 Jun;190(6):682-7.
3. Laryngeal ultrasound: a useful method in predicting post-extubation stridor. A pilot study - Eur . Respir J 2006; 27:384-389
4. Predicting Extubation Failure - Is It in (on) the Cards? - Chest. 2001;120:1061-1063
5. Evaluation of the Cuff-Leak Test in a Cardiac Surgery Population - Chest. 1999;116:1029-1031
6. Evidence-Based Guidelines for Weaning and Discontinuing Ventilatory Support - Chest. 2001;120:375S-396S