Lung volume changes during cleaning of closed endotracheal suction catheters: A randomized crossover study using electrical impedance tomography

Abstract

BACKGROUND: Airway suctioning in mechanically ventilated patients is required to maintain airway patency. Closed suction catheters (CSCs) minimize lung volume loss during suctioning but require cleaning post-suction. Despite their widespread use, there is no published evidence examining lung volumes during CSC cleaning. The study objectives were to quantify lung volume changes during CSC cleaning and to determine whether these changes were preventable using a CSC with a valve in situ between the airway and catheter cleaning chamber. METHODS: This prospective randomized crossover study was conducted in a metropolitan tertiary ICU. Ten patients mechanically ventilated via volume-controlled synchronized intermittent mandatory ventilation (SIMV-VC) and requiring manual hyperinflation (MHI) were included in this study. CSC cleaning was performed using 2 different brands of CSC (one with a valve [Ballard Trach Care 72, Kimberly-Clark, Roswell, Georgia] and one without [Portex Steri-Cath DL, Smiths Medical, Dublin, Ohio]). The maneuvers were performed during both SIMV-VC and MHI. Lung volume change was measured via impedance change using electrical impedance tomography. A mixed model was used to compare the estimated means. RESULTS: During cleaning of the valveless CSC, significant decreases in lung impedance occurred during MHI (-2563 impedance units, 95% CI 2213-2913, P