Laboratory Evaluation of Continuous Cuff Pressure Control Methods

Abstract

Background:

Automatic cuff pressure (Pcuff) control devices (ACPCD) for artificial airways are available, yet there are no standards and few data to support their necessary. We hypothesized that (A) airway pressure change during mechanical ventilation (MV) is transmitted to Pcuff and (B) 3 different ACPCD and 1 manual method will result in zero drift in mean Pcuff during 12 h of simulated MV..

Methods:

Experiments lasted 12 h, at 2 inspiratory target pressures (PIT), with 3 endotracheal tubes (ETT), 3 different ACPCD (Intellicuff Standalone, Pressure Eyes and Tracoe) and 1 manual method, for a total of 24 twelve-hour experimental runs. A Laerdal mannequin was intubated with an 8mm ID ETT and ventilated with: mode = PC-CMV, f (breaths/min) = 20, TI (s) = 1.0, PEEP (cm H₂O) = 10, PIT (cm H₂O above PEEP) = 10 and 40. For ACPCDs, the ETT pilot balloon was connected to the 1st port of a 3-way stopcock. The 2nd port was connected to a pressure transducer and data acquisition system. The 3rd port was connected to the ACPCD. For manual method, the data acquisition system was not used. The ETT was initially inflated to Pcuff = 25 cm H₂O. The final pressure at 12 hours (disconnected from ventilator) was measured with an AG CUFFILL device, corrected for pressure drop due to measurement (-1.1 cm H₂O). The drift in mean Pcuff was calculated as Pdrift = initial mean Pcuff — final mean Pcuff.

Results:

Airway pressure fluctuations from MV were reflected in changing Pcuff amplitudes ranging from 2 to 23 cm H₂O. A large Pdrift occurred with the manual method (-11.1 cm H₂O), but was only ± 0.4 cm H₂O for automatic devices.

Conclusions:

ACPCDs do regulate mean Pcuff and keep Pdrift well below a clinically important threshold. However, the large Pdrift seen with the manual method warrants periodic monitoring. Further studies are needed to determine the source of leak for this method, and the physiologic effects of Pcuff amplitude changes during MV.