Scott J Brady, Dubosky Meagan N, Vines David L, Sulaiman Adewunmi S, Jendral Kyle R, Singh Gagan, Patel Ankeet, Kaplan Carl A, Gurka David P, Balk Robert A
Division of Respiratory Care, Department of Cardiopulmonary Sciences, Rush University, Chicago, Illinois.
Northwestern Memorial Hospital, Chicago, Illinois.
Respir Care. 2017 Nov;62(11):1423-1427. doi: 10.4187/respcare.05391. Epub 2017 Aug 8.
Spontaneous breathing trials (SBTs) are used to assess the readiness for discontinuation of mechanical ventilation. When airway resistance (R) 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. Scraping the ETT can remove the biofilm build-up and decrease mechanical R. The primary aim of this study was to evaluate the impact of ETT scraping on R. The secondary aim was to determine whether decreasing R would impact subsequent SBT success.
Intubated, mechanically ventilated subjects were enrolled if they failed an SBT and had an R of > 10 cm HO/L/s. SBT failure was based on institutional guidelines, and R was 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 The endOclear device was inserted into the ETT and withdrawn per manufacturer's guidelines.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 was compared pre- and post-ETT scraping using a paired test. A Mann-Whitney U test evaluated the difference in percentage change in R between SBT groups.
Twenty-nine subjects completed the study. The mean pre- and post-ETT scraping R values were 15.17 ± 3.83 and 12.05 ± 3.19 cm HO/L/s, respectively ( < .001). Subsequent SBT success was 48%; however, there was no difference in percentage change in R between 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, = .78. No adverse events were noted with ETT scraping.
This study demonstrated that ETT scraping can reduce R. The decrease in R post-ETT scraping did not affect subsequent SBT success.
自主呼吸试验（SBTs）用于评估停止机械通气的时机。当气道阻力（R）升高时，呼吸做功增加可导致机械通气时间延长。气管内插管（ETT）内生物膜和黏液积聚可增加R。刮除ETT可去除生物膜积聚并降低机械R。本研究的主要目的是评估ETT刮除对R的影响。次要目的是确定降低R是否会影响随后SBT的成功率。
如果插管并接受机械通气的受试者SBT失败且R>10 cm H₂O/L/s，则纳入研究。SBT失败依据机构指南判定，R通过使用吸气流量设置为60 L/min的方波流量波形，减去测量的峰压与平台压之差来计算。将EndoClear装置插入ETT并按照制造商指南抽出。重复刮除直至ETT清理干净。使用配对t检验比较ETT刮除前后R的变化。Mann-Whitney U检验评估SBT组之间R百分比变化的差异。
29名受试者完成了研究。ETT刮除前后R的平均数值分别为15.17±3.83和12.05±3.19 cm H₂O/L/s（P<.001）。随后SBT的成功率为48%；然而，随后通过SBT者（18.61%[四分位间距8.90 - 33.93%]）与未通过SBT者（23.88%[四分位间距0.00 - 34.80%]）之间R的百分比变化无差异，U = 78.5，z = -0.284，P = .78。ETT刮除未观察到不良事件。
本研究表明ETT刮除可降低R。ETT刮除后R的降低并未影响随后SBT的成功率。
