Transthoracic ultrasound assessment of B-lines for identifying the increment of extravascular lung water in shock patients requiring fluid resuscitation

Abstract Background: Pulmonary congestion is indicated at lung ultrasound by detection of B-lines, but correlation of these ultrasound signs with pulmonary artery occlusion pressure (PAOP) and extravascular lung water (EVLW) still remains to be further explored. The aim of the study was to assess whether B-lines, and eventually a combination with left ventricular ejection fraction (LVEF) assessment, are useful to differentiate low/high PAOP and EVLW in critically ill patients. Methods: The authors enrolled 73 patients requiring invasive monitoring from the intensive care unit of four university-affiliated hospitals. Forty-one patients underwent PAOP measurement by pulmonary artery catheterization and 32 patients had EVLW measured by transpulmonary thermodilution method. Lung and cardiac ultrasound examinations focused to the evaluation of B-lines and gross estimation of LVEF were performed. The absence of diffuse B-lines (A-pattern) versus the pattern showing prevalent B-lines (B-pattern) and the combination with normal or impaired LVEF were correlated with cutoff levels of PAOP and EVLW. Results: PAOP of 18 mmHg or less was predicted by the A-pattern with 85.7% sensitivity (95% CI, 70.5 to 94.1%) and 40.0% specificity (CI, 25.4 to 56.4%), whereas EVLW 10 ml/kg or less with 81.0% sensitivity (CI, 62.6 to 91.9%) and 90.9% specificity (CI, 74.2 to 97.7%). The combination of A-pattern with normal LVEF increased sensitivity to 100% (CI, 84.5 to 100%) and specificity to 72.7% (CI, 52.0 to 87.2%) for the prediction of PAOP 18 mmHg or less. Conclusions: B-lines allow good prediction of pulmonary congestion indicated by EVLW, whereas are of limited usefulness for the prediction of hemodynamic congestion indicated by PAOP. Combining B-lines with estimation of LVEF at transthoracic ultrasound may improve the prediction of PAOP.

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Assessment of extravascular lung water by measuring the number of pulmonary ultrasound B-lines before and after CBP in patients with MODS

Medicine ◽

10.1097/md.0000000000024181 ◽

2021 ◽

Vol 100 (1) ◽

pp. e24181

Author(s):

Guangke Cao ◽

Yu Wu ◽

Yuliang Zhao ◽

Ling Wang ◽

Yang Zhang

Keyword(s):

Extravascular Lung Water ◽

Lung Water ◽

Before And After ◽

B Lines

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Lung Ultrasound to Quantitatively Evaluate Extravascular Lung Water Content and its Clinical Significance

10.21203/rs.3.rs-19227/v1 ◽

2020 ◽

Author(s):

Guo Guo ◽

Xue-Feng Zhang ◽

Jing Liu ◽

Hai-Feng Zong

Keyword(s):

Extravascular Lung Water ◽

Lung Ultrasound ◽

Rabbit Model ◽

Dry Weight ◽

Type I ◽

Lung Water ◽

Arterial Blood Gas ◽

Injection Volume ◽

Arterial Blood ◽

B Lines

Abstract Background:B-line assessment with lung ultrasound (LUS) has recently been proposed as a reliable, noninvasive semiquantitative tool for evaluating extravascular lung water (EVLW). Currently, there has been no easy quantitative method to evaluate EVLW by LUS. To establish a simple, accurate and clinically operable method for quantitative assessment of EVLW using LUS. Methods:Forty-five New Zealand rabbits were randomized into 9 groups (n=5). After anesthesia, each group of rabbits was injected with different amounts of warm sterile NS (0 ml/kg, 2 ml/kg, 4 ml/kg, 6 ml/kg, 8 ml/kg, 10 ml/kg, 15 ml/kg, 20 ml/kg, 30 ml/kg) via the endotracheal tube. Each rabbit was examined by LUS before and after NS injection. At the same time, the spontaneous respiratory rate (RR, breaths per minute), heart rate (HR, bpm) and arterial blood gas (ABG) of the rabbits were recorded. Then, both lungs were dissected to obtain the wet and dry weight and conduct a complete histological examination.Results:Injecting NS into the lungs through a tracheal tube can successfully establish a rabbit model with increased EVLW. When theNS injection volume is 2~6 ml/kg, comet-tail artifacts and B-lines are the main patterns found on LUS; as additional NS is injected into the lungs, the rabbits' RR gradually increases, while their HR gradually decreases. Confluent B-lines grow gradually but significantly, reaching a dominant position when the NS injection volume reaches 6~8 ml/kg and predominating almost entirely when the NS injection volume is 8~15 ml/kg; at that time, rabbits' RRs and HRs decrease sharply, and the ABG indicated type I respiratory failure (RF). Compact B-lines occur and predominate almost entirely when the NS injection volume reaches 10 ml/kg and 15~20 ml/kg, respectively. At that time, rabbits begin to enter cardiac and respiratory arrest, and ABG shows type II RF and metabolic acidosis (MA).Conclusion: LUS can estimate EVLW content based on the type of B-line.We can give clinical treatment depending on the type of LUS B-line.

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