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 <.001), and significant increases in lung impedance occurred during SIMV (762 impedance units , 95% CI 452-1072, P <.001). In contrast, cleaning of the CSC with a valve in situ resulted in non-significant lung volume changes and maintenance of normal ventilation during MHI and SIMV-VC, respectively (188 impedance units , 95% CI -136 to 511, P = .22; and 22 impedance units , 95% CI -342 to 299, P = .89).
CONCLUSIONS When there is no valve between the airway and suction catheter, cleaning of the CSC results in significant derangements in lung volume . Therefore, the presence of such a valve should be considered essential in preserving lung volumes and uninterrupted ventilation in mechanically ventilated patients.
MeSH: Catheters, Cross-Over Studies, Disinfection, Electric Impedance, Female, Humans, Intensive Care Units, Intubation, Intratracheal, instrumentation, Lung Volume Measurements, Male, Middle Aged, Prospective Studies, Respiration, Artificial, Suction, instrumentation, Tomography