Evaluation of endotracheal tube scraping on airway resistance

Abstract

BACKGROUND: Spontaneous breathing trials (SBTs) are used to assess the readiness for discontinuation of mechanical ventilation. When airway resistance (Raw) is elevated, the imposed work of breathing can lead to prolongation of mechanical ventilation. Biofilm and mucus build-up within the endotracheal tube (ETT) can increase Raw. Scraping the ETT can remove the biofilm build-up and decrease mechanical Raw. The primary aim of this study was to evaluate the impact of ETT scraping on Raw. The secondary aim was to determine whether decreasing Rawwould impact subsequent SBT success. METHODS: Intubated, mechanically ventilated subjects were enrolled if they failed an SBT and had an Rawof > 10 cm H2O/L/s. SBT failure was based on institutional guidelines, and Rawwas calculated by subtracting the difference between the measured peak and plateau pressures using a square flow waveform with an inspiratory flow set at 60 L/min. The endOclear device was inserted into the ETT and withdrawn per manufacturer’s guidelines. Scraping was repeated until the ETT was cleared. Change in Rawwas compared pre- and post-ETT scraping using a paired t test. AMann-Whitney U test evaluated the difference in percentage change in Rawbetween SBT groups. RESULTS: Twenty-nine subjects completed the study. The mean pre- and post-ETT scraping Rawvalues were 15.17 ± 3.83 and 12.05 ± 3.19 cmH2O/L/s, respectively (P