Background

Respiratory variation of inferior vena cava is problematic in predicting fluid responsiveness in patients with right ventricular dysfunction. However, its effectiveness in patients with isolated left ventricular systolic dysfunction (ILVD) has not been reported. We aimed to explore whether inferior vena cava diameter distensibility index (dIVC) can predict fluid responsiveness in mechanically ventilated ILVD patients.

Methods

Patients admitted to the intensive care unit who were on controlled mechanical ventilation and in need of a fluid responsiveness assessment were screened for enrolment. Several echocardiographic parameters, including dIVC, tricuspid annular plane systolic excursion (TAPSE), left ventricular ejection fraction (LVEF), and LV outflow tract velocity–time integral (VTI) before and after passive leg raising (PLR) were collected. Patients with LV systolic dysfunction only (TAPSE ≥ 16 mm, LVEF < 50%) were considered to have isolated left ventricular systolic dysfunction (ILVD).

Results

One hundred and twenty-nine subjects were enrolled in this study, among them, 28 were labelled ILVD patients, and the remaining 101 were patients with normal LV function (NLVF). The value of dIVC in ILVD patients was as high as that in NLVF patients, (20% vs. 16%, p = 0.211). The ILVD group contained a much lower proportion of PLR responders than NLVF patients did (17.9% vs. 53.2%, p < 0.001). No correlation was detected between dIVC and ΔVTI in ILVD patients (r = 0.196, p = 0.309). dIVC was correlated with ΔVTI in NLVF patients (r = 0.722, p < 0.001), and the correlation was strengthened compared with that derived from all patients (p = 0.020). A receiver-operating characteristic (ROC) analysis showed that the area-under-the-curve (AUC) of dIVC for determining fluid responsiveness from ILVD patients was not statistically significant (p = 0.251). In NLVF patients, ROC analysis revealed an AUC of 0.918 (95% CI 0.858–0.978; p < 0.001), which was higher than the AUC derived from all patients (p = 0.033). Patients with LVEF below 40% had a lower ΔVTI and fewer PLR responders than those with LVEF 40–50% and LVEF above 50% (p < 0.001).

Conclusion

dIVC should be used with caution when critically ill patients on controlled mechanical ventilation display normal right ventricular function in combination with abnormal left ventricular systolic function.

中文翻译：

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下腔静脉的呼吸变化无法预测左室功能不全的机械通气患者的液体反应性。

背景

下腔静脉的呼吸变化在预测右心功能不全患者的液体反应性方面存在问题。然而，尚未报道其在孤立的左室收缩功能不全（ILVD）患者中的有效性。我们旨在探讨下腔静脉直径扩张指数（dIVC）是否可以预测机械通气ILVD患者的流体反应性。

方法

筛选入院重症监护病房的患者，这些患者处于受控的机械通气状态，需要进行体液反应性评估，以筛选入组患者。收集了多个超声心动图参数，包括dIVC，三尖瓣环平面收缩期偏移（TAPSE），左心室射血分数（LVEF）和被动抬高腿（PLR）前后的左室流出道速度-时间积分（VTI）。仅患有LV收缩功能障碍（TAPSE≥16 mm，LVEF <50％）的患者被认为患有孤立的左心室收缩功能障碍（ILVD）。

结果

这项研究招募了129名受试者，其中28名被标记为ILVD患者，其余101名具有正常LV功能（NLVF）的患者。ILVD患者的dIVC值与NLVF患者的dIVC值一样高（20％比16％，p  = 0.211）。与NLVF患者相比，ILVD组的PLR反应者比例要低得多（17.9％对53.2％，p  <0.001）。在ILVD患者中，dIVC与ΔVTI之间未发现相关性（r  = 0.196，p  = 0.309）。dIVC与NLVF患者的ΔVTI相关（r  = 0.722，p  <0.001），并且与所有患者的相关性相比，相关性得到加强（p = 0.020）。接受者操作特征（ROC）分析表明，用于确定ILVD患者的液体反应性的dIVC曲线下面积（AUC）在统计学上不显着（p  = 0.251）。在NLVF患者中，ROC分析显示AUC为0.918（95％CI 0.858-0.978；p  <0.001），高于所有患者的AUC（p  = 0.033）。LVEF低于40％的患者比LVEF 40–50％和LVEF高于50％的患者具有更低的ΔVTI和更少的PLR反应（p  <0.001）。

结论

当在机械通气受控制的危重患者中，右心室功能正常且左心室收缩功能异常时，应谨慎使用dIVC。