Noble Vicki E, Murray Alice F, Capp Roberta, Sylvia-Reardon Mary H, Steele David J R, Liteplo Andrew
Department of Emergency Medicine, Division of Nephrology, Massachusetts General Hospital, Boston, MA.
Department of Emergency Medicine, Division of Nephrology, Massachusetts General Hospital, Boston, MA.
Chest. 2009 Jun;135(6):1433-1439. doi: 10.1378/chest.08-1811. Epub 2009 Feb 2.
Sonographic B-lines, also known as lung comets, have been shown to correlate with the presence of extravascular lung water (EVLW). Absent in normal lungs, these sonographic findings become prominent as interstitia and alveoli fill with fluid. Characterization of the dynamics of B-lines, specifically their rate of disappearance as volume is removed, has not been previously described. In this study, we describe the dynamics of B-line resolution in patients undergoing hemodialysis.
Patients undergoing hemodialysis underwent three chest ultrasound examinations: before, at the midpoint, and after dialysis. We followed a previously described chest ultrasound protocol that counts the number of B-lines visualized in 28 lung zones. Baseline demographics, assessment of ejection fraction, time elapsed, net volume of fluid removed, and subjective degree of shortness of breath were recorded for each patient.
Forty of 45 patients completed full dialysis runs and had all three lung scans performed; 6 of 40 patients had zero or one B-line predialysis, and none of these 6 patients gained B-lines during dialysis. Thirty-four of 40 patients had statistically significant reductions in the number of B-lines from predialysis to the midpoint scan and from predialysis to postdialysis with a p value < 0.001. There was no association between subjective dyspnea scores and number of B-lines removed.
B-line resolution appears to occur real-time as fluid is removed from the body, and this change was statistically significant. These data support thoracic ultrasound as a useful method for evaluating real-time changes in EVLW and in assessing a patient's physiologic response to the removal of fluid.
Massachusetts General Hospital trial registration protocol No. 2007P 002226.
超声B线，也称为肺彗星征，已被证明与血管外肺水（EVLW）的存在相关。这些超声表现在正常肺中不存在，当间质和肺泡充满液体时会变得明显。B线动态变化的特征，特别是随着液体排出其消失的速率，此前尚未有描述。在本研究中，我们描述了接受血液透析患者B线消退的动态变化。
接受血液透析的患者在透析前、透析中点和透析后进行了三次胸部超声检查。我们遵循先前描述的胸部超声方案，对28个肺区中可见的B线数量进行计数。记录每位患者的基线人口统计学数据、射血分数评估、经过时间、液体清除净量和主观气短程度。
45例患者中有40例完成了完整的透析过程并进行了所有三次肺部扫描；40例患者中有6例透析前B线为零或一条，这6例患者在透析期间均未增加B线。40例患者中有34例从透析前到中点扫描以及从透析前到透析后B线数量有统计学显著减少，p值<0.001。主观呼吸困难评分与清除的B线数量之间无关联。
随着液体从体内清除，B线似乎实时消退，且这种变化具有统计学显著性。这些数据支持胸部超声作为评估EVLW实时变化以及评估患者对液体清除的生理反应的有用方法。
马萨诸塞州总医院试验注册方案编号2007P 002226。
