Loubieres Y, Vieillard-Baron A, Beauchet A, Fourme T, Page B, Jardin F
Medical Intensive Care Unit, University Hospital Ambroise Paré, Assistance Publique H opitaux de Paris, Boulogne Cedex, France.
Chest. 2000 Dec;118(6):1718-23. doi: 10.1378/chest.118.6.1718.
We hypothesized that a dynamic left ventricular (LV) evaluation during a loading challenge might enhance diagnostic capabilities of routine transesophageal echocardiography in critically ill patients and selection of therapeutic options against circulatory failure, particularly the choice between volume expansion and vasoactive agent infusion.
Prospective clinical study in a group of 26 patients requiring hemodynamic support by vasoactive infusion because of low systemic arterial pressure (< 90 mm Hg by invasive monitoring) during mechanical ventilation.
University hospital ICU.
Patients required respiratory support for an episode of acute respiratory failure of various causes or for an episode of coma. They were studied by transesophageal echocardiography during mechanical ventilation in the controlled mode, before and during a loading challenge made using the legs compartment of medical antishock trousers inflated at 80 mm Hg.
A short-axis view of the left ventricle was obtained by a transgastric approach, and end-diastolic and end-systolic areas were measured. LV stroke area (LVSA) and LV fractional area contraction (LVFAC) were calculated.
Changes in LV echocardiographic measurements permitted separation of the patients into two groups. In nine patients (group 1), LVSA, used as an index of stroke output, was significantly increased during the challenge, together with a significant increase in LV end-diastolic area, suggesting preload improvement by the challenge. Conversely, in 17 patients (group 2), LVSA was significantly reduced by the challenge, together with a significant decrease in LVFAC, suggesting a negative effect of increased afterload by the challenge.
Study of the changes in LV dimensions during loading challenge in hemodynamically unstable patients was used to evaluate the balance between the adequacy of preload and the ability of the heart to pump against an increased load, and might thus guide hemodynamic support.
我们假设在负荷试验期间进行动态左心室（LV）评估可能会增强常规经食管超声心动图对危重症患者的诊断能力，并有助于选择针对循环衰竭的治疗方案，尤其是在容量扩充和血管活性药物输注之间做出选择。
对一组26例因机械通气期间体循环动脉压过低（侵入性监测<90 mmHg）而需要血管活性药物输注进行血流动力学支持的患者进行前瞻性临床研究。
大学医院重症监护病房。
患者因各种原因导致的急性呼吸衰竭发作或昏迷发作而需要呼吸支持。在机械通气的控制模式下，在使用充气至80 mmHg的医用抗休克裤腿部隔室进行负荷试验之前和期间，通过经食管超声心动图对他们进行研究。
通过经胃途径获得左心室短轴视图，并测量舒张末期和收缩末期面积。计算左心室卒中面积（LVSA）和左心室面积分数缩短率（LVFAC）。
左心室超声心动图测量值的变化使患者分为两组。在9例患者（第1组）中，用作心输出量指标的LVSA在试验期间显著增加，同时左心室舒张末期面积也显著增加，表明试验使前负荷得到改善。相反，在17例患者（第2组）中，试验使LVSA显著降低，同时LVFAC也显著降低，表明试验使后负荷增加产生了负面影响。
研究血流动力学不稳定患者在负荷试验期间左心室尺寸的变化，用于评估前负荷充足程度与心脏对抗增加负荷的泵血能力之间的平衡，从而可能指导血流动力学支持。
