The Cuff Leak Test

• As many of us have undoubtedly experienced, we are now extubating patients in the ED due to prolonged lengths of stay
• Critical to extubation is determining whether laryngeal edema may be present
• Laryngeal edema, resulting in airway obstruction, is one of the most common causes of respiratory distress following extubation
• Although shown to have moderate accuracy, many use the 'cuff leak test' to determine the iikelihood of laryngeal edema
• In most studies, performance of the cuff leak test is as follows:
  • take the average of 6 serial measurements of expired tidal volume with the ETT cuff inflated
  • take the average of 6 serial measurements of expired tidal volume with the ETT cuff deflated
  • a difference of < 110 ml between averages strongly suggests the presence of laryngeal edema
• Take Home Point: patients with a cuff leak test < 110 ml are likely to have laryngeal edema and are at high risk of airway obstruction post-extubation.  It is best not to extubate these patients in the ED.

References

Ochoa ME, et al. Cuff leak test for the diagnosis of upper airway obstruction in adults: a systematic review and meta-analysis. Intensive Care Med 2009;35(7):1171-9.