The authors have no acknowledgments.

All procedures performed in the studies involving human participants were conducted in accordance with the ethical standards of the Duke University Health System Institutional Research Committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. The protocol was performed using input from several peer-reviewed papers in the academic literature2,13,14,15. Imaging was performed on the authors themselves for the normal images and as part of routine educational ultrasound scans done for teaching purposes for the positive images, with preceding verbal consent obtained as per institutional standards. The patients were selected based on certain criteria. Specifically, the inclusion criterion was any patient with hypotension, and the exclusion criterion was patient refusal to undergo an ultrasound exam.
1. Safety procedures
<ol>
	<li>Utilize nonsterile nitrile or latex gloves depending on the patient&#39;s allergies. Additional safety precautions may be required based on the clinical context. Please refer to the respective institution&#39;s infection control policies, and follow any precautions in place.</li>
</ol>
2. Probe selection
<ol>
	<li>For infants (i.e., children younger than 1 year of age), perform the sonographic evaluation of the IVC with either a low-frequency or high-frequency (&#62;5 MHz) ultrasound transducer, depending on the infant&#39;s body size. 
	&#8203;NOTE: IVC evaluation in infants is a specialized pediatric topic beyond the scope of this review. The remainder of this review solely focuses on imaging the IVC in individuals over 1 year of age.</li>
	<li>For individuals over 1 year of age, visualize the IVC with any low-frequency (&#8804;5 MHz) ultrasound transducer, such as a linear phased-array sector arc probe or curvilinear probe. 
	NOTE: The linear phased-array sector arc probe is commonly referred to as a phased-array probe. This term is misleading, since all modern ultrasound transducers use phasing to steer the ultrasound beam16,17. However, for the sake of brevity, throughout this review, we will use the term phased-array probe instead of linear phased-array sector arc probe.
	<ol>
		<li>The phased-array probe is the optimal probe for both main types of external cardiac ultrasound: transthoracic echocardiography (TTE) and focused cardiac ultrasound (FoCUS)18. When performing either TTE or FoCUS to evaluate the heart, continue using the phased-array transducer for the IVC portion of each exam rather than switching to another low-frequency probe.</li>
	</ol>
	</li>
</ol>
3. Machine preset
<ol>
	<li>Set the machine to the cardiology convention by using the Cardiac Preset function, which sets the indicator to the left of the screen. Set the screen refresh rate to &#62;20 Hz. 
	NOTE: The IVC evaluation can be performed in the Abdominal Mode. However, for the same points mentioned in step 2.2.1, it is far more convenient to utilize the same presets for both a FoCUS exam and a POCUS IVC exam.</li>
	<li>Set the mode to B-Mode (2-dimensional grayscale). Set the depth to 6-20 cm, depending on the depth of the IVC in each patient.</li>
</ol>
4. Scanning technique
<ol>
	<li>Apply ultrasound gel to the transducer.</li>
	<li>Obtain the anterior IVC short-axis (ANT IVC SAX) view.
	<ol>
		<li>Position the patient in the supine position with both hips flexed, if tolerated by the patient.</li>
		<li>Place the ultrasound probe centered on the patient&#39;s anterior midline just caudal to the xiphoid process in the coronal plane, with the transducer indicator mark pointing toward the patient&#39;s left (Figure 1).</li>
		<li>Adjust the depth so that the IVC and aorta appear in the middle third of the screen and the spine is visible (Video 1).</li>
		<li>For setting the axis, fan the ultrasound beam cranially or caudally until both the IVC and the abdominal aorta appear in the short-axis cross-section as rounded structures (Video 1).</li>
		<li>Decrease the gain until the blood in the IVC is either completely black or just a few specks of grey are visible (Video 1).</li>
		<li>Once all the settings are done, click on Acquire.</li>
	</ol>
	</li>
	<li>Obtain the anterior IVC long-axis (ANT IVC LAX) view.
	<ol>
		<li>Position the patient in the supine position with both hips flexed, if tolerated by the patient.</li>
		<li>Position the probe for obtaining the ANT IVC SAX view as described in step 4.2, center the view on the IVC, and rotate the ultrasound probe 90&#176; counterclockwise, without translating the probe, such that the probe&#39;s indicator faces cranially at the end of the rotation (Figure 2).</li>
		<li>Adjust the depth so that the IVC appears in the middle third of the screen and the liver tissue is visible deeper than the IVC (Video 2).</li>
		<li>For setting the axis, fan the ultrasound beam toward the patient&#39;s left or right until the IVC appears as a rectangular, intrahepatic structure spanning from cranial to caudal on the screen. (Video 2).</li>
		<li>Decrease the gain until the blood in the IVC is either completely black or just a few specks of grey are visible (Video 2).</li>
		<li>Once all the settings are done, click on Acquire.</li>
		<li>Optional: Quantify the IVC anterior-to-posterior (AP) diameter (Figure 3).
		<ol>
			<li>With a live image of the IVC optimized as per step 4.3.6, click on Freeze. Click on Caliper or Measure, depending on the machine&#39;s measurement button.</li>
			<li>Move the trackball to the anterior wall of the IVC approximately 1-2 cm caudal from the hepatic vein confluence. Click on Select.</li>
			<li>Move the trackball to the posterior wall of the IVC opposite the point in step 4.3.7.2, such that the line between the two points is roughly perpendicular to the long axis of the IVC. Click on Select, and then click on Acquire.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Obtain the right lateral IVC long-axis (RL IVC LAX) view.
	<ol>
		<li>Position the patient in the supine position with the legs flat and the right arm moved away from the patient&#39;s side, either overhead or outstretched laterally, so as to allow access to the right flank.</li>
		<li>Place the probe transducer in the coronal plane with the indicator pointing cranially in the sixth or seventh right intercostal space just anterior to the right mid-axillary line (Figure 4).</li>
		<li>Adjust the depth so that the IVC appears in the middle third of the screen and the liver tissue is visible deeper than the IVC (Video 3).</li>
		<li>For setting the axis, fan the ultrasound beam anteriorly or posteriorly until the IVC is visualized as a rectangular, intrahepatic structure spanning from cranial to caudal on the screen (Video 3).</li>
		<li>Decrease the gain until the blood in the IVC is either completely black or just a few specks of grey are visible (Video 3). Click on Acquire.</li>
	</ol>
	</li>
	<li>Obtain the right lateral IVC short-axis (RL IVC SAX) view.
	<ol>
		<li>Continue positioning the patient supine with the legs flat and the right arm moved away from the patient&#39;s side, either overhead or outstretched laterally, so as to allow access to the right flank.</li>
		<li>Continue positioning the probe in the position used for obtaining the RL IVC LAX view (see step 4.4), center the view on the IVC, and rotate the ultrasound probe 90&#176; clockwise, without translating the probe, such that the probe&#39;s indicator faces anteriorly at the end of the rotation (Figure 5).</li>
		<li>Adjust the depth so that the IVC appears in the middle third of the screen and the liver tissue, aorta, and spine are all visible deeper than the IVC (Video 4).</li>
		<li>For setting the axis, fan the ultrasound beam cranially or caudally until the IVC and abdominal aorta are visible in the short-axis view as rounded structures (Video 4).</li>
		<li>Decrease the gain until the blood in the IVC is either completely black or just a few specks of grey are visible (Video 4). Click on Acquire.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Hashim, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+utility+of+point+of+care+ultrasonography+(POCUS).">The utility of point of care ultrasonography (POCUS).</a> Annals of Medicine and Surgery. 71, 102982 (2021).</li><li>Finnerty, N. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inferior+vena+cava+measurement+with+ultrasound:+What+is+the+best+view+and+best+mode.">Inferior vena cava measurement with ultrasound: What is the best view and best mode.</a> The Western Journal of Emergency Medicine. 18 (3), 496-501 (2017).</li><li>Aslan, Y., Arslan, G., Saracoglu, K. T., Eler Cevik, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+ultrasonographic+measurement+of+vena+cava+inferior+diameter+on+the+prediction+of+post-spinal+hypotension+in+geriatric+patients+undergoing+spinal+anaesthesia.">The effect of ultrasonographic measurement of vena cava inferior diameter on the prediction of post-spinal hypotension in geriatric patients undergoing spinal anaesthesia.</a> International Journal of Clinical Practice. 75 (10), 14622 (2021).</li><li>Vander Mullen, J., Wise, R., Vermeulen, G., Moonen, P. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Usefulness+of+ultrasonographic+measurement+of+the+diameter+of+the+inferior+vena+cava+to+predict+responsiveness+to+intravascular+fluid+administration+in+patients+with+cancer.">Usefulness of ultrasonographic measurement of the diameter of the inferior vena cava to predict responsiveness to intravascular fluid administration in patients with cancer.</a> Proceedings. 29 (4), 374-377 (2016).</li><li>Via, G., Tavazzi, G., Price, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ten+situations+where+inferior+vena+cava+ultrasound+may+fail+to+accurately+predict+fluid+responsiveness:+A+physiologically+based+point+of+view.">Ten situations where inferior vena cava ultrasound may fail to accurately predict fluid responsiveness: A physiologically based point of view.</a> Intensive Care Medicine. 42 (7), 1164-1167 (2016).</li><li>Lee, C. W., Kory, P. D., Arntfield, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+fluid+resuscitation+protocol+using+inferior+vena+cava+and+lung+ultrasound.">Development of a fluid resuscitation protocol using inferior vena cava and lung ultrasound.</a> Journal of Critical Care. 31 (1), 96-100 (2016).</li><li>Ruge, M., Marhefka, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IVC+measurement+for+the+noninvasive+evaluation+of+central+venous+pressure.">IVC measurement for the noninvasive evaluation of central venous pressure.</a> Journal of Echocardiography. 20 (3), 133-143 (2022).</li><li>Privratsky, J. R., Schroder, V. T., Hashmi, N., Bronshteyn, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Initial+evaluation+for+low-pressure+cardiac+tamponade+using+focused+cardiac+ultrasound.">Initial evaluation for low-pressure cardiac tamponade using focused cardiac ultrasound.</a> A&amp;A Practice. 11 (12), 356-358 (2018).</li><li>Rudski, L. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guidelines+for+the+echocardiographic+assessment+of+the+right+heart+in+adults:+a+report+from+the+American+Society+of+Echocardiography+endorsed+by+the+European+Association+of+Echocardiography,+a+registered+branch+of+the+European+Society+of+Cardiology,+and+the+Canadian+Society+of+Echocardiography.">Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography.</a> Journal of the American Society of Echocardiography. 23 (7), 685-713 (2010).</li><li>Blehar, D. J., Resop, D., Chin, B., Dayno, M., Gaspari, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inferior+vena+cava+displacement+during+respirophasic+ultrasound+imaging.">Inferior vena cava displacement during respirophasic ultrasound imaging.</a> Critical Ultrasound Journal. 4 (1), 18 (2012).</li><li>Kisslo, J., vonRamm, O. T., Thurstone, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+imaging+using+a+phased+array+ultrasound+system.+II.+Clinical+technique+and+application.">Cardiac imaging using a phased array ultrasound system. II. Clinical technique and application.</a> Circulation. 53 (2), 262-267 (1976).</li><li>vonRamm, O. T., Thurstone, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+imaging+using+a+phased+array+ultrasound+system.+I.+System+design.">Cardiac imaging using a phased array ultrasound system. I. System design.</a> Circulation. 53 (2), 258-262 (1976).</li><li>Via, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=International+evidence-based+recommendations+for+focused+cardiac+ultrasound.">International evidence-based recommendations for focused cardiac ultrasound.</a> Journal of the American Society of Echocardiography. 27 (7), 1-33 (2014).</li><li>Bhardwaj, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combination+of+inferior+vena+cava+diameter,+hepatic+venous+flow,+and+portal+vein+pulsatility+index:+Venous+excess+ultrasound+score+(VEXUS+score)+in+predicting+acute+kidney+injury+in+patients+with+cardiorenal+syndrome:+A+prospective+cohort+study.">Combination of inferior vena cava diameter, hepatic venous flow, and portal vein pulsatility index: Venous excess ultrasound score (VEXUS score) in predicting acute kidney injury in patients with cardiorenal syndrome: A prospective cohort study.</a> Indian Journal of Critical Care Medicine. 24 (9), 783-789 (2020).</li><li>Klein, A. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=American+Society+of+Echocardiography+clinical+recommendations+for+multimodality+cardiovascular+imaging+of+patients+with+pericardial+disease:+Endorsed+by+the+Society+for+Cardiovascular+Magnetic+Resonance+and+Society+of+Cardiovascular+Computed+Tomography.">American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: Endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography.</a> Journal of the American Society of Echocardiography. 26 (9), 965-1012 (2013).</li><li>Au, A. 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The authors have nothing to disclose.

Even when properly imaged, information garnered from the IVC should not be the sole data point used for guiding treatment. The exact same IVC size and respirophasic changes can be seen in both normal states and in pathologic conditions. Therefore, the clinical context is critically important for guiding how to interpret the IVC data. Further, when using ultrasound to assess a patient&#39;s intravascular volume status, the published literature is mixed as to what thresholds of IVC size and respirophasic change accurately ...

Over the last several decades, the accessibility of point-of-care ultrasound (POCUS) has increased dramatically. Providers across medical disciplines can now integrate POCUS into their bedside exams and more readily identify important contributors to patients&#39; conditions1. For example, in acute care settings, one of the most important areas of focus is the assessment and management of volume status2. Inadequate fluid resuscitation can result in tissue hypoperfusion, end-organ dysfunction, and severe acid-base abnormalities. However, overzealous fluid administration is associated with worsened mortality3. The determination of volume status has primarily been accomplished using the combination&#160;of physical exam findings and dynamic hemodynamic measures, including pulse pressure variation, central venous pressure, and/or fluid challenges via either passive leg-raise testing or intravenous fluid boluses4. With the growing availability of POCUS devices, some providers are seeking to use ultrasound imaging to supplement these measures5. The sonographic assessment of the anterior-to-posterior dimension of the IVC and the respirophasic change in that dimension can assist in the assessment of right atrial pressure and, possibly, intravascular volume status6,7,8,9.
Notably, however, the relationship between IVC parameters (i.e., size and respirophasic change) and volume responsiveness is distorted in many common situations, including but not limited to, the following: (1) passively ventilated patients receiving either high positive end-expiratory pressure (PEEP) or low tidal volumes; (2) spontaneously breathing patients making either small or large respiratory effort; (3) lung hyperinflation; (4) conditions impairing venous return (e.g., right ventricular dysfunction, tension pneumothorax, cardiac tamponade, etc.); and (5) increased abdominal compart pressure10.
While the utility of IVC sonography as a standalone measure for assessing the intravascular volume status is debated5,10,11,12, there is no debate about the fact that its use as a diagnostic tool requires imaging in standardized ways and the ability to utilize alternative views when a single vantage point proves to be inadequate2. Toward this end, this manuscript defines the four sonographic views of the IVC, illustrates common sonographic pitfalls and how to avoid them, and provides examples of both typical and extreme IVC sonographic states. There are four views in which the IVC can be adequately visualized by transabdominal sonography: anterior short-axis, anterior long-axis, right lateral long-axis, and right lateral short-axis. The protocol below describes a standardized method of image acquisition.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Edge 1 ultrasound machine</td>
			<td>SonoSite</td>
			<td>n/a</td>
			<td>Used to obtain all adequate and inadequate images/clips</td>
		</tr>
	</tbody>
</table>

image acquisition method for the sonographic assessment of the inferior vena cava

Over the past several decades, clinicians have incorporated several applications of diagnostic point-of-care ultrasound (POCUS) into medical decision-making. Among the applications of POCUS, imaging the inferior vena cava (IVC) is practiced by a wide variety of specialties, such as nephrology, emergency medicine, internal medicine, critical care, anesthesiology, pulmonology, and cardiology. Although each specialty uses IVC data in slightly different ways, most medical specialties, at minimum, attempt to use IVC data to make predictions about intravascular volume status. While the relationship between IVC sonographic data and intravascular volume status is complex and highly context-dependent, all clinicians should collect the sonographic data in standardized ways to ensure repeatability. This paper describes standardized IVC image acquisition including patient positioning, transducer selection, probe placement, image optimization, and the pitfalls and limitations of IVC sonographic imaging.&#160;This paper also describes the commonly performed anterior IVC long-axis view and three other views of the IVC that can each provide helpful diagnostic information when the anterior long-axis view is difficult to obtain or interpret.

Adequate exam 
There is no single caliber or respirophasic behavior of the IVC that can be considered universally normal in all circumstances. For instance, the IVC seen in Videos 1-4 and Figure 3 was imaged in a healthy, hydrated male experiencing no acute illness. However, notably, this patient&#39;s &#34;normal&#34; IVC has a relatively large AP diameter, &#62;2 cm in the ANT IVC LAX view, and shows minimal respiroph...

Watch this Scientific Journal Video about Image Acquisition Method for the Sonographic Assessment of the Inferior Vena Cava at JoVE.com

Image Acquisition Method for the Sonographic Assessment of the Inferior Vena Cava

Point-of-care ultrasound evaluation of the inferior vena cava (IVC) is commonly utilized to identify, among other things, the volume status. Imaging should be performed systematically to ensure repeatability. This manuscript reviews the methods and pitfalls of sonographic IVC examination.

Over the past several decades, clinicians have incorporated several applications of diagnostic point-of-care ultrasound (POCUS) into medical ...

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JoVE Journal

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3.2K Views.  Duke University School of Medicine. Point-of-care ultrasound evaluation of the inferior vena cava (IVC) is commonly utilized to identify, among other things, the volume status. Imaging should be performed systematically to ensure repeatability. This manuscript reviews the methods and pitfalls of sonographic IVC examination.

Video: Image Acquisition Method for the Sonographic Assessment of the Inferior Vena Cava

Electrolytic Inferior Vena Cava Model (EIM) of Venous Thrombosis

Animal models serve a vital role in deep venous thrombosis (DVT) research in order to study thrombus formation, thrombus resolution and to test potential therapeutic compounds (1). New compounds to be utilized in the treatment and prevention of DVT are currently being developed. The delivery of potential therapeutic antagonist compounds to an affected thrombosed vein has been problematic. In the context of therapeutic applications, a model that uses partial stasis and consistently generates thrombi within a major vein has been recently established. The Electrolytic Inferior vena cava Model (EIM) is mouse model of DVT that permits thrombus formation in the presence of continuous blood flow. This model allows therapeutic agents to be in contact with the thrombus in a dynamic fashion, and is more sensitive than other models of DVT (1). In addition, this thrombosis model closely simulates clinical situations of thrombus formation and is ideal to study venous endothelial cell activation, leukocyte migration, venous thrombogenesis, and to test therapeutic applications (1). The EIM model is technically simple, easily reproducible, creates consistent thrombi sizes and allows for a large sample (i.e. thrombus and vein wall) which is required for analytical purposes.

Electrolytic Inferior Vena Cava Model EIM of Venous Thrombosis

The electrolytic induction of endothelial activation to the internal surface of the Inferior Vena Cava results in venous type thrombus formation due to endothelial activation and partial blood stasis, two components of Virchow's triad.

Animal models serve a vital role in deep venous thrombosis (DVT) research in order to study thrombus formation, thrombus resolution and to test potential ...

Mouse Complete Stasis Model of Inferior Vena Cava Thrombosis

Venous thromboembolism (VTE) includes both deep vein thrombosis (DVT) and pulmonary embolism (PE). In the United States (U.S.), the high morbidity and mortality rates make VTE a serious health concern 1-2. After heart disease and stroke, VTE is the third most common vascular disease 3. In the U.S. alone, there is an estimated 900,000 people affected each year, with 300,000 deaths occurring annually 3. A reliable in vivo animal model to study the mechanisms of this disease is necessary.
The advantages of using the mouse complete stasis model of inferior vena cava thrombosis are several. The mouse model allows for the administration of very small volumes of limited availability test agents, reducing costs dramatically. Most promising is the potential for mice with gene knockouts that allow specific inflammatory and coagulation factor functions to be delineated. Current molecular assays allow for the quantitation of vein wall, thrombus, whole blood, and plasma for assays. However, a major concern involving this model is the operative size constraints and the friability of the vessels. Also, due to the small IVC sample weight (mean 0.005 grams) it is necessary to increase animal numbers for accurate statistical analysis for tissue, thrombus, and blood assays such as real-time polymerase chain reaction (RT-PCR), western blot, enzyme-linked immunosorbent (ELISA), zymography, vein wall and thrombus cellular analysis, and whole blood and plasma assays 4-8.
The major disadvantage with the stasis model is that the lack of blood flow inhibits the maximal effect of administered systemic therapeutic agents on the thrombus and vein wall.

The mouse complete stasis model of inferior vena cava thrombosis yields quantifiable amounts of vein wall tissue and thrombus. It has proven useful for evaluating interactions between the vein wall and the occlusive thrombus and in assessing the progression from acute to chronic inflammation.

Venous thromboembolism (VTE) includes both deep vein thrombosis (DVT) and pulmonary embolism (PE).  In the United States (U.S.), the high morbidity and ...

Implantation of Inferior Vena Cava Interposition Graft in Mouse Model

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. The long-term clinical results showed excellent patency rates, however, with significant incidence of stenosis. To investigate the cellular and molecular mechanisms of vascular neotissue formation and prevent stenosis development in tissue engineered vascular grafts (TEVGs), we developed a mouse model of the graft with approximately 1 mm internal diameter. First, the TEVGs were assembled from biodegradable tubular scaffolds fabricated from a polyglycolic acid nonwoven felt mesh coated with &#949;-caprolactone and L-lactide copolymer. The scaffolds were then placed in a lyophilizer, vacuumed for 24 hr, and stored in a desiccator until cell seeding. Second, bone marrow was collected from donor mice and mononuclear cells were isolated by density gradient centrifugation. Third, approximately one million cells were seeded on a scaffold and incubated O/N. Finally, the seeded scaffolds were then implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. The implanted grafts demonstrated excellent patency (&#62;90%) without evidence of thromboembolic complications or aneurysmal formation. This murine model will aid us in understanding and quantifying the cellular and molecular mechanisms of neotissue formation in the TEVG.

To improve our knowledge of cellular and molecular neotissue formation, a murine model of the TEVG was recently developed. The grafts were implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. This model achieves similar results to those achieved in our clinical investigation, but over a far shortened time-course.

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. ...

Patch Angioplasty in the Rat Aorta or Inferior Vena Cava

Pericardial patches are commonly used in vascular surgery to close vessels. To facilitate studies of the neointimal hyperplasia that forms on the patch, we developed a rat model of patch angioplasty that can be used in either a vein or an artery, creating a patch venoplasty or a patch arterioplasty, respectively. Technical aspects of this model are discussed. The infra-renal IVC or aorta are dissected and then clamped proximally and distally. A 3 mm venotomy or arteriotomy is performed in the infrarenal inferior vena cava or aorta of 6 to 8 week-old Wistar rats. A bovine pericardial patch (3 mm x 1.5 mm x 0.6 mm) is then used to close the site using a 10-0 nylon suture. Compared to arterial patches, venous patches show increased neointimal thickness on postoperative day 7. This novel model of pericardial patch angioplasty can be used to examine neointimal hyperplasia on vascular biomaterials, as well as to compare the differences between the arterial and venous environments.

We have established a model of pericardial patch angioplasty that can be used in either small-diameter veins or arteries. This model can be used to compare venous and arterial neointimal hyperplasia formation.

Pericardial patches are commonly used in vascular surgery to close vessels. To facilitate studies of the neointimal hyperplasia that forms on the patch, ...

A Rat Model of Orthotopic Liver Transplantation Using a Novel Magnetic Anastomosis Technique for Suprahepatic Vena Cava Reconstruction

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep learning curve. The introduction of the cuff technique for anastomosis of the portal vein (PV) and infrahepatic vena cava (IHVC) has significantly simplified the transplant procedure in rats. However, due to the short anterior wall of the recipients' suprahepatic vena cava (SHVC), the cuff technique is very difficult to use for the reconstruction of the SHVC. Most researchers in this field still use the hand-suture technique for SHVC reconstruction, which makes it the bottleneck step in rat orthotopic liver transplantation. The magnetic anastomosis technique (i.e., magnamosis) is a method of connecting two vessels using the attractive force between two magnets. Our recent study has shown that the magnetic anastomosis technique is superior to the hand-suture technique for SHVC reconstruction in rats. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using the novel magnetic anastomosis technique. In this model, the reconstruction of the PV and IHVC was performed by the standard cuff technique, while the reconstruction of the bile duct (BD) was performed by a stent technique. The hepatic re-arterialization was not performed. The magnetic anastomosis technique made SHVC reconstruction much easier and significantly shortened the anphepatic phase. After a reasonable learning curve, even researchers without advanced microsurgical skills can produce reliable and reproducible results using this rat model of OLT.

The reconstruction of the suprahepatic vena cava (SHVC) remains a difficult step in rat orthotopic liver transplantation. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using a novel magnetic anastomosis technique.

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep ...

'Boden Food Plate': Novel Interactive Web-based Method for the Assessment of Dietary Intake

Different methods can be used in research to assess dietary intake, many of which are still paper-based. Written estimated food diaries are often utilized in clinical trials, despite being a burden for both study participants and researchers. This method requires participant literacy, it is time consuming, labor intensive, and can easily lead to under-reporting. With advancements in technology, there is a growing interest in electronic diaries that automate the dietary assessment process. These are focused on improving accuracy, reducing both time and cost and providing users with a visual and more enjoyable experience. The methodology presented here aimed to validate the &#39;Boden Food Plate&#39;, a novel web-based platform for self-recording of food and drink items, compared to a traditional estimated food diary. The application was also rated on a satisfaction scale by study participants using a paper-based questionnaire. Sixty-seven participants completed the dietary measures on both the three-day electronic and paper food diaries. For the analysis, only dietary data completed at both study time points (baseline and week six) was utilized. Despite small mean differences between dietary data collection methods, Bland Altman analysis showed fairly wide 95% limits of agreement between the electronic platform and the written estimated food diary and there were few cases which did not fall within the 95% confidence intervals. Overall, participants found the electronic food diary to be more fun than the paper method and as easy to use as hard copy diaries. The new platform has potential as a self-recording tool for the collection of dietary data, particularly when utilized in clinical trial settings. However, further validation studies are needed to improve the validity of this novel electronic dietary data collection tool.

&#039;Boden Food Plate&#039;: Novel Interactive Web-based Method for the Assessment of Dietary Intake

The &#39;Boden Food Plate&#39; is an electronic food diary designed to be an interactive and fun method to collect dietary intake using visual depictions. The purpose of this study was to validate the web-based application against a traditional three-day estimated food diary method.

Different methods can be used in research to assess dietary intake, many of which are still paper-based. Written estimated food diaries are often utilized ...

Troubleshooting FoCUS Image Acquisition: Patient Positioning, Transducer Manipulation, and Image Optimization

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography to add real-time information to patient care. These bedside exams are problem oriented, rapidly and repeatedly performed, and largely qualitative in nature. Competency in FoCUS includes mastery of the stereotactic and psychomotor skills required for transducer manipulation and image acquisition. Competency also requires the ability to optimize the setup, troubleshoot image acquisition, and understand the sonographic limitations because of complex clinical environments and patient pathology. This article presents concepts for successful, high-quality two-dimensional (B-mode) image acquisition in FoCUS.
Concepts of high-quality image acquisition can be applied to all established sonographic windows of the FoCUS exam: the parasternal long-axis (PLAX), parasternal short-axis (PSAX), apical four chamber (A4C), subcostal fourchamber (SC4C), and the inferior vena cava (IVC). The apical five-chamber (A5C) and subcostal short-axis (SCSA) views are mentioned, but are not discussed in-depth. A pragmatic figure illustrating the movements of the phased array transducer is also provided to serve as a cognitive aid during FoCUS image acquisition.

Here, we present a protocol to allow providers to perform focused cardiac ultrasound (FoCUS) in the clinical environment. We describe methods of transducer manipulation, review common pitfalls of transducer movements, and suggest tips to optimize phased array transducer use.

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography to add real-time information to patient care. These ...

A Modified Sonographic Algorithm for Image Acquisition in Life-Threatening Emergencies in the Critically Ill Newborn

The use of routine point-of-care ultrasound (POCUS) is increasing in neonatal intensive care units (NICUs), with several centers advocating for 24 h equipment availability. In 2018, the sonographic algorithm for life-threatening emergencies (SAFE) protocol was published, which allows the assessment of neonates with sudden decompensation to identify abnormal contractility, tamponade, pneumothorax, and pleural effusion. In the study unit (with a consulting neonatal hemodynamics and POCUS service), the algorithm was adapted by including consolidated core steps to support at-risk newborns, aiding clinicians in managing cardiac arrest, and adding views to verify correct intubation. This paper presents a protocol that can be applied in the NICU and the delivery room (DR) in relation to three scenarios: cardiac arrest, hemodynamic deterioration, or respiratory decompensation. 
This protocol can be performed with a state-of-the-art ultrasound machine or an affordable handheld device; the image acquisition protocol is carefully detailed. This method was designed to be learned as a general competence to obtain the timely diagnosis of life-threatening scenarios; the method aims to save time but does not represent a substitute for comprehensive and standardized hemodynamic and radiological analyses by a multidisciplinary team, which might not universally be on call but needs to be involved in the process. From January 2019 to July 2022, in our center, 1,045 hemodynamic consultation/POCUS consults were performed with 25 patients requiring the modified SAFE protocol (2.3%), and a total of 19 procedures were performed. In five cases, trained fellows on call resolved life-threatening situations. Clinical examples are provided that show the importance of including this technique in the care of critical newborns.

Here, we present a protocol that can be applied in the neonatal intensive care unit and the delivery room in relation to three scenarios: cardiac arrest, hemodynamic deterioration, or respiratory decompensation. This protocol can be performed with a state-of-the-art ultrasound machine or an affordable handheld device; an image acquisition protocol is carefully detailed.

The use of routine point-of-care ultrasound (POCUS) is increasing in neonatal intensive care units (NICUs), with several centers advocating for 24 h ...

Focused Assessment with Sonography for Trauma (FAST) Exam: Image Acquisition

Over the past twenty years, the Focused Assessment with Sonography for Trauma (FAST) exam has transformed the care of patients presenting with a combination of trauma (blunt or penetrating) and hypotension. In these hemodynamically unstable trauma patients, the FAST exam permits rapid and noninvasive screening for free pericardial or peritoneal fluid, the latter of which implicates intra-abdominal injury as a likely contributor to the hypotension and justifies emergent abdominal surgical exploration. Further, the abdominal portion of the FAST exam can also be used outside of the trauma setting to screen for free peritoneal fluid in patients who become hemodynamically unstable in any context, including after procedures that may inadvertently injure abdominal organs. These "non-trauma" situations of hemodynamic instability are often triaged by providers from specialties other than emergency medicine or trauma surgery who are not familiar with the FAST exam. Therefore, there is a need to promulgate knowledge about the FAST exam to all clinicians caring for critically ill patients. Toward this end, this article describes FAST exam image acquisition: patient positioning, transducer selection, image optimization, and exam limitations. Since the free fluid is likely to be found in specific anatomic locations that are unique for each canonical FAST exam view, this work centers on the unique image acquisition considerations for each window: subcostal, right upper quadrant, left upper quadrant, and pelvis.

Focused Assessment with Sonography for Trauma FAST Exam: Image Acquisition

The Focused Assessment with Sonography for Trauma (FAST) exam is a diagnostic point-of-care ultrasound examination used to screen for the presence of free fluid in the pericardium and peritoneum. Indications, techniques, and pitfalls of the procedure are discussed in this article.

Over the past twenty years, the Focused Assessment with Sonography for Trauma (FAST) exam has transformed the care of patients presenting with a ...

Rodent Venoplasty Balloon Model for Deep Vein Treatment Studies

Rodent Inferior Vena Cava Venoplasty Balloon Model

Balloon venoplasty is a commonly used clinical technique to treat deep vein stenosis and occlusion as a consequence of trauma, congenital anatomic abnormalities, acute deep vein thrombosis (DVT), or stenting. Chronic deep venous obstruction is histopathologically characterized by thrombosis, fibrosis, or both. Currently, no direct treatment is available to target these pathological processes. Therefore, a reliable in vivo animal model to test novel interventions is necessary. The rodent survival inferior vena cava (IVC) venoplasty balloon model (VBM) allows the study of balloon venoplasty in non-thrombotic and post-thrombotic conditions across multiple time points. The local and systemic effect of coated and uncoated venoplasty balloons can be quantified via tissue, thrombus, and blood assays such as real-time polymerase chain reaction (RT-PCR), western blot, enzyme-linked immunosorbent assay (ELISA), zymography, vein wall and thrombus cellular analysis, whole blood and plasma assays, and histological analysis. The VBM is reproducible, replicates surgical human interventions, can identify local vein wall-thrombi protein changes, and allows multiple analyses from the same sample, decreasing the number of animals required per group.

Author Spotlight: Utilizing Venoplasty Balloon Model in Rodents to Simulate Surgical Interventions for Deep Veins

The protocol presents a survival rodent model to test venoplasty balloon (VB) interventions in non-thrombotic, thrombotic, and post-thrombotic deep veins.