Cuff Leak Test and Airway Obstruction in Mechanically Ventilated ICU

The Respiratory Therapist (RT) will perform the CLT on all enrolled patients. The patients will first be switched to volume assist-control (V-AC) with a respiratory rate of 10 breaths/min (to allow patient assist), constant flow of 60 l/min, and tidal volume set to match the average tidal volume currently being delivered during supportive ventilation. The RT will document the average exhaled volume over 3-5 breaths after switching to V-AC. The test will be performed by deflating the ETT balloon cuff with a 10 cc syringe, and: a) auscultation with a stethoscope to identify audible air leak around the ETT, and b) measuring the difference between the average exhaled volume prior to cuff deflation and the average exhaled volume over 3-5 breaths after cuff deflation.