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Two Chronically Ill Patients Presenting With Hypoxemic Respiratory Failure FREE TO VIEW

Luke A. Seaburg, MD; Hiroshi Sekiguchi, MD
Author and Funding Information

CORRESPONDENCE TO: Hiroshi Sekiguchi, MD, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905


Copyright 2016, American College of Chest Physicians. All Rights Reserved.


Chest. 2016;149(4):e107-e110. doi:10.1016/j.chest.2015.10.084
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Published online

A 67-year-old woman with a past medical history significant for allogeneic bone marrow transplantation for acute myeloid leukemia developed neutropenic fever and was admitted to the hospital. On presentation, she was found to be hypoxic, with saturations of 86% while breathing room air, and a temperature of 38.5°C. Her blood pressure was 122/80 mm Hg and her heart rate was 122 beats/min. Laboratory testing demonstrated an absolute neutrophil count of 660 cells/μL, with electrolyte levels in the normal range. She was treated for Klebsiella bacteremia and cytomegalovirus viremia. Unfortunately, she developed severe acute respiratory distress and was administered high-frequency oscillatory ventilation. Her chest radiograph is shown in Figure 1. Because of hemodynamic instability, the decision was made to insert a central venous catheter to initiate administration of a vasoactive agent. Preprocedural scanning of the right internal jugular vein by ultrasonography revealed the following (Video 1).

Figure 1
Figure Jump LinkFigure 1 Chest radiograph demonstrating nodular and interstitial opacities bilaterally.Grahic Jump Location

A 70-year-old man with recently diagnosed stage IV lung adenocarcinoma was admitted to the ICU with hypoxemic respiratory failure and worsening malignant pleural effusion. A few weeks previously he had been diagnosed with bilateral pulmonary emboli (PE) (Fig 2); however, his anticoagulation treatment had been discontinued because of intracranial metastases. On presentation, he was tachypneic and required oxygen at 9 L/min to maintain his oxygen saturations in the low 90% range. Vascular critical care ultrasonography was done at the bedside to assess for DVT in the lower extremity as the source of suspected new PE. No DVT was identified; however, the examination demonstrated the following findings (Video 2).

Figure 2
Figure Jump LinkFigure 2 Chest CT scan demonstrating subsegmental pulmonary emboli. White arrow denotes a clot.Grahic Jump Location

Question: What is the phenomenon seen in the videos?

Answer: Spontaneous echo contrast (SEC). SEC is indicative of a low-flow hypercoagulable state, which may predispose patients to thromboembolic disease.

Spontaneous echo contrast (SEC) (Video 3), or “echo smoke,” is an ultrasound finding of a swirling, dynamic smokelike pattern, which is often visualized in the cardiac chambers., It is a pattern of increased blood echogenicity caused by ultrasonic backscatter from red cell aggregates. These aggregates form because of noncovalent binding between red cells and plasma proteins under low-flow and low-shear conditions.,,

Clinically, it is thought to represent a hypercoagulable state and is known to be associated with increased inflammatory markers such as C-reactive protein, fibrinogen, and von Willebrand factor., Studies on SEC in the left atrium demonstrated its association with a high prevalence of thromboembolic disease, including cerebrovascular disease, in patients with sinus rhythm and atrial fibrillation., In patients with atrial fibrillation, it has been shown to predict a future ischemic embolization.,, Most clinical studies were conducted on SEC in the left atrium; however, similar clinical and prognostic significance has been reported in other parts of the cardiovascular system. The presence of SEC in the thoracic aorta has been shown to be associated with an increased risk for future myocardial infarction and cardiac mortality. SEC in the right atrium was shown to correlate with an increased incidence of PE. SEC in the carotid artery was frequently seen in patients with ischemic cerebrovascular disease. More recently, SEC in the internal jugular vein was reported to be a possible independent risk factor for ischemic cerebrovascular accidents.,

In the first patient, the presence of SEC in the internal jugular vein reinforced the findings reported previously, as the patient’s fibrinogen level was elevated at 504 mg/dL (normal range, 175-430 mg/dL) in the setting of overwhelming sepsis. In addition, the use of high-frequency oscillatory ventilation caused an increase in intrathoracic pressure, leading to a low-flow state in the internal jugular vein. While the patient’s findings would suggest that she was at elevated risk for thromboembolic phenomenon, there were no emboli discovered on autopsy. The patient’s proinflammatory and prothromboembolic state may have been counteracted by her profound thrombocytopenia. Her platelet count was less than 15,000 cells/dL during this admission.

In the second patient, vascular critical care ultrasonography demonstrated SEC in the femoral vein in the setting of recently diagnosed PE, although no acute or chronic DVT was identified. A repeat comprehensive vascular ultrasonography confirmed these findings. SEC is occasionally observed during vascular ultrasonography in the presence of slow venous flow; however, its potential impact on future thromboembolic disease and clinical implications are unknown. At present, there is no clinical recommendation available on quantification or grading of SEC in vascular ultrasonography, and SEC is not generally reported in the absence of DVT on examination. In echocardiography, the semiquantitative method has been proposed in the assessment and grading of SEC. In this case, the patient did not undergo inferior vena cava filter placement, because of the absence of acute DVT. His anticoagulation treatment was withheld, given his brain metastasis. Eight months later, he was diagnosed with recurrent PE and died.

In summary, SEC is an interesting phenomenon that is identified by echocardiography and vascular ultrasonography. It represents increased blood echogenicity caused by ultrasonic backscatter from red cell aggregates and suggests the presence of a low-flow, hypercoagulable state in the cardiovascular system. As point-of-care ultrasound use increases, SEC of large venous structures is likely to be seen by more physicians, especially in critically ill patients. Future studies are needed to evaluate its prevalence and clinical importance, specifically the benefits and risks of anticoagulation treatment in patients with SEC in the deep venous system and its potential as a marker of future venous thromboembolism events.

  • 1.

    SEC can be seen within the venous system of critically ill patients.

  • 2.

    SEC seen in the left atrium is a risk factor for thromboembolism in patients with either sinus rhythm or atrial fibrillation.

  • 3.

    While the exact clinical significance of vascular SEC is unknown, a recent study demonstrated that SEC in the internal jugular vein is an independent risk factor for ischemic cerebrovascular accidents.

Author contributions: L. A. S. and H. S. had full access to all of the data in the study and take responsibility for the content. H. S. contributed to ultrasound and data collection as well as the conception of the paper. L. A. S. contributed to primary drafting of the manuscript and creation and editing of videos. L. A. S. and H. S. contributed to the paper design, chart review, and revision of the manuscript.

Other contributions:CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.

Additional information: To analyze this case with the videos, see the online article.

IRB Review: This project was reviewed by the Mayo Clinic Institutional Review Board and was deemed IRB exempt.

Kamath G.S. .Herweg B. .Cotiga D. .et al Activation of the endogenous coagulation system in patients with atrial flutter: relationship to echocardiographic markers of thromboembolic risk. Cardiol J. 2010;17:390-396 [PubMed]journal. [PubMed]
 
Yasuoka Y. .Naito J. .Hirooka K. .et al Right atrial spontaneous echo contrast indicates a high incidence of perfusion defects in pulmonary scintigraphy in patients with atrial fibrillation. Heart Vessels. 2009;24:32-36 [PubMed]journal. [CrossRef] [PubMed]
 
Sadanandan S. .Sherrid M.V. . Clinical and echocardiographic characteristics of left atrial spontaneous echo contrast in sinus rhythm. J Am Coll Cardiol. 2000;35:1932-1938 [PubMed]journal. [CrossRef] [PubMed]
 
Conway D.S.G. .Buggins P. .Hughes E. .et al Relation of interleukin-6, C-reactive protein, and the prothrombotic state to transesophageal echocardiographic findings in atrial fibrillation. Am J Cardiol. 2004;93:1368-1373 [PubMed]journal. [CrossRef] [PubMed]
 
Dawn B. .Varma J. .Singh P. .et al Cardiovascular death in patients with atrial fibrillation is better predicted by left atrial thrombus and spontaneous echocardiographic contrast as compared with clinical parameters. J Am Soc Echocardiogr. 2005;18:199-205 [PubMed]journal. [CrossRef] [PubMed]
 
Hsu H.-Y. .Chung C.-P. .Chen S.-Y. .et al Spontaneous echo contrast in internal jugular veins: a probable indicator for systemic inflammation and a prothrombotic state. Ultrasound Med Biol. 2012;38:926-932 [PubMed]journal. [CrossRef] [PubMed]
 
Bernhardt P. .Schmidt H. .Hammerstingl C. .et al Patients with atrial fibrillation and dense spontaneous echo contrast at high risk a prospective and serial follow-up over 12 months with transesophageal echocardiography and cerebral magnetic resonance imaging. J Am Coll Cardiol. 2005;45:1807-1812 [PubMed]journal. [CrossRef] [PubMed]
 
Steinberg E.H. .Madmon L. .Wesolowsky H. .et al Prognostic significance of spontaneous echo contrast in the thoracic aorta: relation with accelerated clinical progression of coronary artery disease. J Am Coll Cardiol. 1997;30:71-75 [PubMed]journal. [CrossRef] [PubMed]
 
Onozuka H. .Muraki M. .Mikami T. .et al Prevalence and clinical importance of spontaneous echo contrast within the carotid artery in patients with ischemic cerebrovascular disease. J Ultrasound Med. 2007;26:169-177 [PubMed]journal. [PubMed]
 
Fatkin D. .Loupas T. .Jacobs N. .et al Quantification of blood echogenicity: evaluation of a semiquantitative method of grading spontaneous echo contrast. Ultrasound Med Biol. 1995;21:1191-1198 [PubMed]journal. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1 Chest radiograph demonstrating nodular and interstitial opacities bilaterally.Grahic Jump Location
Figure Jump LinkFigure 2 Chest CT scan demonstrating subsegmental pulmonary emboli. White arrow denotes a clot.Grahic Jump Location

Tables

References

Kamath G.S. .Herweg B. .Cotiga D. .et al Activation of the endogenous coagulation system in patients with atrial flutter: relationship to echocardiographic markers of thromboembolic risk. Cardiol J. 2010;17:390-396 [PubMed]journal. [PubMed]
 
Yasuoka Y. .Naito J. .Hirooka K. .et al Right atrial spontaneous echo contrast indicates a high incidence of perfusion defects in pulmonary scintigraphy in patients with atrial fibrillation. Heart Vessels. 2009;24:32-36 [PubMed]journal. [CrossRef] [PubMed]
 
Sadanandan S. .Sherrid M.V. . Clinical and echocardiographic characteristics of left atrial spontaneous echo contrast in sinus rhythm. J Am Coll Cardiol. 2000;35:1932-1938 [PubMed]journal. [CrossRef] [PubMed]
 
Conway D.S.G. .Buggins P. .Hughes E. .et al Relation of interleukin-6, C-reactive protein, and the prothrombotic state to transesophageal echocardiographic findings in atrial fibrillation. Am J Cardiol. 2004;93:1368-1373 [PubMed]journal. [CrossRef] [PubMed]
 
Dawn B. .Varma J. .Singh P. .et al Cardiovascular death in patients with atrial fibrillation is better predicted by left atrial thrombus and spontaneous echocardiographic contrast as compared with clinical parameters. J Am Soc Echocardiogr. 2005;18:199-205 [PubMed]journal. [CrossRef] [PubMed]
 
Hsu H.-Y. .Chung C.-P. .Chen S.-Y. .et al Spontaneous echo contrast in internal jugular veins: a probable indicator for systemic inflammation and a prothrombotic state. Ultrasound Med Biol. 2012;38:926-932 [PubMed]journal. [CrossRef] [PubMed]
 
Bernhardt P. .Schmidt H. .Hammerstingl C. .et al Patients with atrial fibrillation and dense spontaneous echo contrast at high risk a prospective and serial follow-up over 12 months with transesophageal echocardiography and cerebral magnetic resonance imaging. J Am Coll Cardiol. 2005;45:1807-1812 [PubMed]journal. [CrossRef] [PubMed]
 
Steinberg E.H. .Madmon L. .Wesolowsky H. .et al Prognostic significance of spontaneous echo contrast in the thoracic aorta: relation with accelerated clinical progression of coronary artery disease. J Am Coll Cardiol. 1997;30:71-75 [PubMed]journal. [CrossRef] [PubMed]
 
Onozuka H. .Muraki M. .Mikami T. .et al Prevalence and clinical importance of spontaneous echo contrast within the carotid artery in patients with ischemic cerebrovascular disease. J Ultrasound Med. 2007;26:169-177 [PubMed]journal. [PubMed]
 
Fatkin D. .Loupas T. .Jacobs N. .et al Quantification of blood echogenicity: evaluation of a semiquantitative method of grading spontaneous echo contrast. Ultrasound Med Biol. 1995;21:1191-1198 [PubMed]journal. [CrossRef] [PubMed]
 
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