Xia Jing, Qian Chuan-Yun, Yang Li, Li Mei-Ju, Liu Xiao-Xue, Yang Ting, Lu Qin
1Emergency Department, The First Affiliated Hospital of Kunming Medical University, 295 Xi Chang Road, Kunming, 650032 Yunnan China.
2Multidisciplinary Intensive Care Unit, Department of Anesthesiology and Critical Care, La Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Paris, France.
J Intensive Care. 2019 Dec 2;7:54. doi: 10.1186/s40560-019-0409-x. eCollection 2019.
A spontaneous breathing trial (SBT) is a major diagnostic tool to predict successfully extubation in patients. Several factors may lead to weaning failure, including the degree of lung aeration loss and diaphragm dysfunction. The main objective was to compare the diaphragmatic contractility between patients with high lung aeration loss and low lung aeration loss during a 30-minute SBT by ultrasound.
This was a prospective single-center study. Lung ultrasound aeration score (LUS) and diaphragmatic thickening fraction (DTF) were measured during mechanical ventilation 1 h before SBT (T-1), 30 min (T1), and 120 min (T2) after the start of the SBT during quiet breathing. The right and left DTF were compared between patients with LUS ≥ 14 (high lung aeration loss), considered at high risk of post-extubation distress, and those with LUS < 14 (low lung aeration loss). The relationship between the LUS and DTF and the changes in LUS and DTF from T-1 to T2 in patients with LUS ≥ 14 were assessed.
Forty-nine patients were analyzed; 33 had LUS ≥ 14 and 16 had LUS < 14 at T1. The DTF at T1 was significantly higher in patients with LUS ≥ 14 than in those with LUS < 14: the right median (IQR) DTF was 22.2% (17.1 to 30.9%) vs. 14.8% (10.2 to 27.0%) ( = 0.035), and the left median (IQR) DTF was 25.0% (18.4 to 35.0%) vs. 18.6% (9.7 to 24.2%) ( = 0.017), respectively. There was a moderate positive correlation between the LUS and the DTF (Rho = 0.3, = 0.014). A significant increase in the LUS was observed from T-1 to T1, whereas no change was found between T1 and T2. The DTF remained stable from T-1 to T2.
During a SBT, diaphragmatic contraction acts differently depending on the degree of pulmonary aeration. In patients with high lung aeration loss, increased diaphragmatic contractility indicates an additional respiratory effort to compensate lung volume loss that would contribute to successful SBT. Further studies are needed to evaluate the combined evaluation of lung aeration and diaphragmatic function to predict the successful weaning of patients from mechanical ventilation.
自主呼吸试验（SBT）是预测患者能否成功脱机的主要诊断工具。多种因素可能导致撤机失败，包括肺通气丧失程度和膈肌功能障碍。主要目的是通过超声比较30分钟SBT期间肺通气丧失程度高的患者与肺通气丧失程度低的患者之间的膈肌收缩力。
这是一项前瞻性单中心研究。在SBT开始前1小时（T-1）、SBT开始后30分钟（T1）和120分钟（T2）的静息呼吸期间进行机械通气时，测量肺超声通气评分（LUS）和膈肌增厚分数（DTF）。比较LUS≥14（肺通气丧失程度高，被认为拔管后呼吸窘迫风险高）的患者与LUS<14（肺通气丧失程度低）的患者的左右DTF。评估LUS≥14的患者中LUS与DTF之间的关系以及从T-1到T2的LUS和DTF变化。
分析了49例患者；在T1时，33例患者LUS≥14，16例患者LUS<14。LUS≥14的患者在T1时的DTF显著高于LUS<14的患者：右侧中位数（IQR）DTF为22.2%（17.1%至30.9%），而左侧为14.8%（10.2%至27.0%）（P=0.035）；左侧中位数（IQR）DTF分别为25.0%（18.4%至35.0%）和18.6%（9.7%至24.2%）（P=0.017）。LUS与DTF之间存在中度正相关（Rho=0.3，P=0.014）。从T-1到T1观察到LUS显著增加，而T1和T2之间未发现变化。DTF从T-1到T2保持稳定。
在SBT期间，膈肌收缩根据肺通气程度的不同而表现不同。在肺通气丧失程度高的患者中，膈肌收缩力增加表明为补偿肺容积丧失而进行的额外呼吸努力，这有助于SBT成功。需要进一步研究评估肺通气和膈肌功能的联合评估，以预测患者机械通气的成功撤机。
