Ultrasonography of the diaphragm is the subject of a growing interest in the intensive care unit (ICU) setting [1–6]. Observing the diaphragm in its zone of apposition allows measurement of its thickness and computation of its thickening fraction (TFdi), which depends on diaphragmatic activity [3] and reflects the diaphragm work of breathing [1]. A recent study showed that the TFdi correlated well with the endotracheal pressure variation generated by phrenic stimulation [6]. This index was also proposed for clinical evaluation of diaphragm weakness to detect ventilator-induced diaphragmatic dysfunction (VIDD) and predict difficult weaning [3, 4]. However, it remains unclear whether increased thickening in this setting only reflects a better intrinsic diaphragmatic strength, or if it also suggests enhanced work of breathing in response to increased cardiorespiratory workload. Furthermore, some authors suggested that VIDD could be thought as the “respiratory” manifestation of a global neuromuscular weakness [4, 7], but its relationship with ICU-acquired limb weakness is not straightforward [5]. The present study had a dual objective: first, to explore the correlation between ICU-acquired limb weakness (as assessed by the Medical Research Council (MRC) score) and diaphragm thickening (as assessed by TFdi); second, to assess the association of clinical variables with TFdi during mechanical ventilation. Diaphragm thickening does not correlate with ICUAW; it is influenced by cardiopulmonary load and residual sedation http://ow.ly/6TC130e6G3Q

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机械通气期间膈肌增厚部分的决定因素：一项随机试验的辅助研究

膈肌超声检查是重症监护病房 (ICU) 环境中越来越受关注的主题 [1-6]。在对合区观察膈肌可以测量其厚度并计算其增厚分数 (TFdi)，这取决于膈肌活动 [3] 并反映呼吸的膈肌功 [1]。最近的一项研究表明，TFdi 与膈刺激产生的气管内压力变化密切相关 [6]。该指数还被提议用于膈肌无力的临床评估，以检测呼吸机引起的膈肌功能障碍 (VIDD) 并预测撤机困难 [3, 4]。然而，目前尚不清楚在这种情况下增厚是否仅反映了更好的固有膈肌强度，或者如果它还表明呼吸功增强以应对增加的心肺工作负荷。此外，一些作者认为 VIDD 可以被认为是整体神经肌肉无力的“呼吸”表现 [4, 7]，但它与 ICU 获得性肢体无力的关系并不简单 [5]。本研究有双重目标：首先，探索 ICU 获得性肢体无力（由医学研究委员会 (MRC) 评分评估）与膈肌增厚（由 TFdi 评估）之间的相关性；其次，评估机械通气期间临床变量与 TFdi 的关联。膈肌增厚与ICUAW无关；它受心肺负荷和残余镇静的影响 http://ow.ly/6TC130e6G3Q 一些作者认为 VIDD 可以被认为是整体神经肌肉无力的“呼吸”表现 [4, 7]，但它与 ICU 获得性肢体无力的关系并不简单 [5]。本研究有双重目标：首先，探索 ICU 获得性肢体无力（由医学研究委员会 (MRC) 评分评估）与膈肌增厚（由 TFdi 评估）之间的相关性；其次，评估机械通气期间临床变量与 TFdi 的关联。膈肌增厚与ICUAW无关；它受心肺负荷和残余镇静的影响 http://ow.ly/6TC130e6G3Q 一些作者认为 VIDD 可以被认为是整体神经肌肉无力的“呼吸”表现 [4, 7]，但它与 ICU 获得性肢体无力的关系并不简单 [5]。本研究有双重目标：首先，探索 ICU 获得性肢体无力（由医学研究委员会 (MRC) 评分评估）与膈肌增厚（由 TFdi 评估）之间的相关性；其次，评估机械通气期间临床变量与 TFdi 的关联。膈肌增厚与ICUAW无关；它受心肺负荷和残余镇静的影响 http://ow.ly/6TC130e6G3Q 本研究有双重目标：首先，探索 ICU 获得性肢体无力（由医学研究委员会 (MRC) 评分评估）与膈肌增厚（由 TFdi 评估）之间的相关性；其次，评估机械通气期间临床变量与 TFdi 的关联。膈肌增厚与ICUAW无关；它受心肺负荷和残余镇静的影响 http://ow.ly/6TC130e6G3Q 本研究有双重目标：首先，探索 ICU 获得性肢体无力（由医学研究委员会 (MRC) 评分评估）与膈肌增厚（由 TFdi 评估）之间的相关性；其次，评估机械通气期间临床变量与 TFdi 的关联。膈肌增厚与ICUAW无关；它受心肺负荷和残余镇静的影响 http://ow.ly/6TC130e6G3Q