Adult Cuff Leak Test Calculator

Calculate cuff leak volume and percent from tidal volumes recorded during a quantitative cuff leak test in an intubated adult.

Which volumes to enter

This calculator uses the Miller and Cole volume-based approach. Enter the protocol’s inspired tidal volume. Then enter the mean of the three lowest expired volumes from the first six breaths after cuff deflation, or enter those six readings and let the calculator find the mean.

Before entering volumesUse readings from the same test. Confirm the inspired volume and review unexpected readings against the ventilator record and your local protocol.

How will you enter expired volumes?

Cuff leak volume and percent

  • Volume = inspired tidal volume − average expired tidal volume
  • Percent = (cuff leak volume ÷ inspired tidal volume) × 100

Fictional example. An inspired volume of 450 mL and average expired volume of 330 mL give a leak of 120 mL, or 26.67% of the 450 mL inspired volume.

Where the test fits in extubation assessment

ATS/CHEST suggests cuff leak testing for mechanically ventilated adults who otherwise meet extubation criteria and are considered at high risk for post-extubation stridor. A reduced leak can raise concern for upper-airway obstruction after extubation. A measurable leak can still occur in patients who develop stridor.

Thresholds vary across studies and protocols. Document the measurement method and use the result alongside the airway assessment. This calculator reports the measured difference and percentage without assigning a risk category or a pass/fail result.

References