EA4533, Université Paris-Sud, Le Kremlin-Bicêtre, France,
Intensive Care Med. 2015 Mar;41(3):487-94. doi: 10.1007/s00134-015-3653-0. Epub 2015 Jan 24.
Weaning-induced cardiac dysfunction is more likely to occur if the heart does not tolerate the changes in loading conditions induced by spontaneous breathing trial (SBT). We hypothesized that the presence of cardiac preload independence before an SBT is associated with weaning failure related to cardiac dysfunction.
We included 30 patients after a first failed 1-h T-tube SBT who had a transpulmonary thermodilution already in place. Preload independence [no increase in the pulse contour analysis-derived cardiac index ≥10 % during passive leg raising (PLR)] was assessed before the second SBT. Failure of the SBT related to cardiac dysfunction was defined by an increase in pulmonary artery occlusion pressure above 18 mmHg at the end of the SBT associated with clinical intolerance.
Fifty-seven SBTs were analyzed. The SBT failed in 46 cases. Overall, 31 failed SBTs were associated with weaning-induced cardiac dysfunction. During PLR, the cardiac index did not change in cases of failed SBTs with cardiac dysfunction, whereas it significantly increased in the other cases: 4 % (interquartile range, IQR 0-5) vs. 12 % (IQR 11-15), respectively. If PLR did not increase the cardiac index by more than 10 % before the SBT, the occurrence of SBT failure related to cardiac dysfunction was predicted with a sensitivity of 97 % [95 % confidence interval (CI) 83-100], specificity of 81 % (95 % CI 61-93) and area under the receiver-operating characteristic curve of 0.88 (95 % CI 0.78-0.98).
Preload independence assessed by a negative PLR test performed before an SBT predicts weaning failure related to cardiac dysfunction.
如果心脏不能耐受自主呼吸试验（SBT）引起的负荷条件变化，更有可能发生撤机诱导性心功能障碍。我们假设，在 SBT 前存在心脏前负荷独立性与与心功能障碍相关的撤机失败有关。
我们纳入了 30 名首次 1 小时 T 管 SBT 失败的患者，这些患者已经进行了经肺温度稀释法。在第二次 SBT 前评估前负荷独立性[被动抬腿（PLR）期间脉搏轮廓分析衍生心指数无增加≥10%]。SBT 相关的心脏功能障碍失败定义为 SBT 结束时肺动脉闭塞压增加超过 18mmHg，同时伴有临床不耐受。
分析了 57 次 SBT。46 例 SBT 失败。总体而言，31 次 SBT 失败与撤机诱导性心功能障碍有关。在 PLR 期间，心功能障碍导致 SBT 失败的病例中，心指数没有变化，而在其他病例中，心指数显著增加：4%（四分位距，IQR 0-5）比 12%（IQR 11-15）。如果 SBT 前 PLR 不能使心指数增加 10%以上，则可以预测 SBT 与心功能障碍相关的失败，其灵敏度为 97%[95%置信区间（CI）83-100]，特异性为 81%（95%CI 61-93），受试者工作特征曲线下面积为 0.88（95%CI 0.78-0.98）。
在 SBT 前进行阴性 PLR 试验评估的前负荷独立性可以预测与心功能障碍相关的撤机失败。
