Evaluation of endotracheal tube scraping on airway resistance

BACKGROUND: Spontaneous breathing trials (SBTs) are used to assess the readiness for discontinuation of mechanical ventilation. When airway resistance (R_aw) 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 R_aw. Scraping the ETT can remove the biofilm build-up and decrease mechanical R_aw. The primary aim of this study was to evaluate the impact of ETT scraping on R_aw. The secondary aim was to determine whether decreasing R_awwould impact subsequent SBT success. METHODS: Intubated, mechanically ventilated subjects were enrolled if they failed an SBT and had an R_awof > 10 cm H₂O/L/s. SBT failure was based on institutional guidelines, and R_awwas 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 The endOclear device was inserted into the ETT and withdrawn per manufacturer’s guidelines.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 R_awwas compared pre- and post-ETT scraping using a paired t test. AMann-Whitney U test evaluated the difference in percentage change in R_awbetween SBT groups. RESULTS: Twenty-nine subjects completed the study. The mean pre- and post-ETT scraping R_awvalues were 15.17 ± 3.83 and 12.05 ± 3.19 cmH₂O/L/s, respectively (P<.001). Subsequent SBT success was 48%; however, there was no difference in percentage change in R_awbetween subsequent passed SBT (18.61% [interquartile range 8.90–33.93%]) and failed SBT (23.88% [interquartile range 0.00–34.80%]), U = 78.5, z = –0.284, P =.78. No adverse events were noted with ETT scraping. CONCLUSIONS: This study demonstrated that ETT scraping can reduce R_aw. The decrease in R_awpost-ETT scraping did not affect subsequent SBT success.