The authors wish to acknowledge Dr. Paul Zamudio, a specialist in Nephrology and Critical Care, for his contributions to this manuscript.

1. Assess Extravascular Compartment Before Diuresis: Chest Ultrasound
<ol>
	<li>Use a low-frequency, phased array probe.</li>
	<li>Select the appropriate machine setting (abdomen or lung) with the screen marker operator-left.</li>
	<li>Adjust the depth to 8-12 cm.</li>
	<li>Place the patient in supine or semi-recumbent position and expose the anterior chest. Place the transducer at a 90&#176; angle to the patient&#39;s anterior chest with the probe marker facing cephalad.
	<ol>
		<li>Perform this protocol at the midclavicular line in two locations on each side of the chest for a total of four locations: in the 2nd-3rd or the 3rd-4th intercostal space, and in the 4th-5th or 5th-6th intercostal space.</li>
		<li>Visualize B-lines, if present. 
		NOTE: B lines are echogenic artifacts with a narrow origin on the pleural line, and they move synchronously with respiratory movements (Figure 1).</li>
	</ol>
	</li>
	<li>Count the number of B-lines in each scan plane to quantify the extent of pulmonary edema. 
	NOTE: Up to one B-line is normal; two to three B-lines represent mild pulmonary edema, whereas 4 or more B-lines represent moderate to severe edema; a whiteout pattern with no A-lines represents very severe pulmonary edema (Figure 2).</li>
</ol>
2. Assess Intravascular Compartment Before Diuresis: IVC Ultrasound
<ol>
	<li>Use a low frequency, phased array probe.</li>
	<li>Select the cardiac machine setting with the screen marker operator-right and adjust the depth to 12-21 cm for optimal image resolution.</li>
	<li>Place the patient in a supine position and expose the anterior chest. Place the transducer at a 90&#176; angle to the patient&#39;s sub-xiphoid region with the probe marker facing cephalad.
	<ol>
		<li>Perform this protocol with the transducer located just right of the midline, tilted slightly right-lateral and cephalad.</li>
		<li>By scanning right-to-left, visualize both the IVC and the aorta.</li>
		<li>Note that the objective is to visualize the cavo-atrial junction, diaphragm, liver, hepatic vein, and IVC in its longitudinal plane. The aorta is visualized by angulating the scan plane medially (Figure 3).</li>
	</ol>
	</li>
	<li>Once the IVC and the cavo-atrial junction have been identified, set the ultrasound to M-Mode to measure the anterior-posterior diameter of the IVC.
	<ol>
		<li>Using the touch pad, select the M-mode beam that corresponds to a near-orthogonal section, 2-4 cm distal to the cavo-atrial junction just beyond the visible hepatic vein.</li>
		<li>Select the M-mode button a second time, and freeze the screen after the M-mode reading is complete through at least 1 respiratory cycle.</li>
		<li>Use machine calipers for all measurements, measuring the vessel from internal edge to internal edge.</li>
	</ol>
	</li>
	<li>Measure D-max and D-min during a normal respiratory cycle.</li>
</ol>
3. Set Fluid Management Goals Based on Gradation of Pulmonary Edema and Diameter of IVC
<ol>
	<li>Assess the lung ultrasound to determine the need for diuresis (Figure 2).</li>
	<li>Assess the IVC ultrasound to determine the patient&#39;s ability to withstand diuresis (Figure 3).</li>
</ol>
4. Reassess Extravascular and Intravascular Compartments Throughout Diuretic Therapy.
<ol>
	<li>Repeat the protocol as outlined above every 6 hours to evaluate the progress of diuretic therapy and to guide fluid management goals.</li>
</ol>

<ol>
	<li>Zoccali, C., 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=Pulmonary+congestion+predicts+cardiac+events+and+mortality+in+ESRD.">Pulmonary congestion predicts cardiac events and mortality in ESRD.</a> Journal of the Amerian Society of Nephrology. 24, 639-646 (2013).</li><li>Vitturi, N., 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=Lung+ultrasound+during+hemodialysis,+the+role+in+the+assessment+of+volume+status.">Lung ultrasound during hemodialysis, the role in the assessment of volume status.</a> International Urology and Nephrology. 46, 169-174 (2014).</li><li>Noble, V. E., 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=Ultrasound+assessment+for+extravascular+lung+water+in+patients+undergoing+hemodialysis.+Time+course+for+resolution.">Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis. Time course for resolution.</a> Chest. 135, 1433-1439 (2009).</li><li>Lang, R. 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=Recommendations+for+Cardiac+Chamber+Quantification+by+Echocardiography+in+Adults:+An+Update+from+the+American+Society+of+Echocardiography+and+the+European+Association+of+Cardiovascular+Imaging.">Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.</a> Journal of the American Society of Echocardiography. 28, 1-39 (2015).</li><li>Barbier, C., 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=Respiratory+changes+in+inferior+vena+cava+diameter+are+helpful+in+predicting+fluid+responsiveness+in+ventilated+septic+patients.">Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients.</a> Intensive Care Medicine. 30, 1740-1746 (2004).</li><li>Feissel, 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=The+respiratory+variation+in+inferior+vena+cava+diameter+as+a+guide+to+fluid+therapy.">The respiratory variation in inferior vena cava diameter as a guide to fluid therapy.</a> Intensive Care Medicine. 30, 1834-1837 (2004).</li><li>Lichtenstein, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lung+ultrasound+in+the+critically+ill.">Lung ultrasound in the critically ill.</a> Annals of Intensive Care. 4, 1 (2014).</li><li>Lichtenstein, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BLUE-Protocol+and+FALLS-Protocol:+Two+Applications+of+Lung+Ultrasound+in+the+Critically+Ill.">BLUE-Protocol and FALLS-Protocol: Two Applications of Lung Ultrasound in the Critically Ill.</a> Chest. 147, 1659-1670 (2015).</li><li>Moore, C. L., Copel, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Point-of-care+ultrasonography.">Point-of-care ultrasonography.</a> New England Journal of Medicine. 364, 749-757 (2011).</li><li>Lichtenstein, D., 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=A-lines+and+B-lines:+lung+ultrasound+as+a+bedside+tool+for+predicting+pulmonary+artery+occlusion+pressure+in+the+critically+ill.">A-lines and B-lines: lung ultrasound as a bedside tool for predicting pulmonary artery occlusion pressure in the critically ill.</a> Chest. 136, (2009).</li><li>Trezzi, 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=Lung+ultrasonography+for+the+assessment+of+rapid+extravascular+water+variation,+evidence+from+hemodialysis+patients.">Lung ultrasonography for the assessment of rapid extravascular water variation, evidence from hemodialysis patients.</a> Internal and Emergency Medicine. 8, 409-415 (2013).</li><li>Lyon, M., Blaivas, M., Brannam, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonographic+measurement+of+the+inferior+vena+cava+as+a+marker+of+blood+loss.">Sonographic measurement of the inferior vena cava as a marker of blood loss.</a> American Journal of Emergency Medicine. 23, 45-50 (2005).</li><li>Katzarski, K. S., 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=A+critical+evaluation+of+ultrasound+measurement+of+inferior+vena+cava+diameter+in+assessing+dry+weight+in+normotensive+and+hypertensive+hemodialysis+patients.">A critical evaluation of ultrasound measurement of inferior vena cava diameter in assessing dry weight in normotensive and hypertensive hemodialysis patients.</a> American Journal of Kidney Disease. 30, 459-465 (1997).</li><li>Goyfman, 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=Combined+aquaretic+and+diuretic+therapy+in+acute+heart+failure.">Combined aquaretic and diuretic therapy in acute heart failure.</a> International Journal of Nephrology and Renovascular Disease. 10, 129-134 (2017).</li></ol>

The authors have nothing to disclose.

Many studies have demonstrated that bedside US is a reliable diagnostic tool that can be used to guide the management of various disease states such as shock and dyspnea5. The correlation of B-lines with extravascular lung water has good sensitivity and specificity in evaluating for pulmonary edema, and studies have shown that lung US can reliably detect even modest variations in extravascular lung water2,10. Similarly, studies have shown that IVC diameter, as measured by US techniques, is a reliable indicator of intravascular volume loss12,13. As it represents intravascular volume status, IVC diameter determines whether a patient can withstand aggressive diuresis. Taken together, chest and IVC US techniques can be used to determine the level of diuresis needed to resolve pulmonary edema, assess the patient's ability to withstand diuresis, and monitor the progress of fluid removal therapy. 
Utilization of the Reverse-FALLS protocol allows the clinician to perform an initial evaluation of a patient's intravascular and extravascular volume status, while repetition of the protocol at six-hour intervals provides an objective measurement of treatment progress and allows for augmentation of diuretic therapy as needed. It is important to note that 6 hour intervals are necessary to allow diuretic therapy to reach its maximum effect and to provide adequate time for equilibration of intravascular and extravascular volumes. If IVC caliber is small and collapsible but B-lines persist on lung US, it may be necessary to delay diuretic therapy until the patient's fluid compartments equilibrate further. Clinicians must be cautious to avoid depleting intravascular volume in an attempt to reduce extravascular fluid. Failure to do so may lead to hypotension and a decrease in cardiac output, which could have grave consequences. These measurements must also be considered with the patient's clinical picture, as well as laboratory measurements that provide insight into other disease processes at play, such as serum electrolytes or serum albumin levels. 
If IVC US reveals a large and noncompliant vessel, however, then an aggressive approach to fluid removal may be necessary. The approach to diuretic therapy is largely dependent on individual patient factors, as preexisting hemodynamics and comorbidities such as diuretic naivety or chronicity, or preexisting Chronic Kidney Disease may alter the effects of diuretic medications. Standardized therapy with furosemide (IV 10-40 mg/h or boluses) may be initiated and subsequently titrated based on chest and IVC US in combination with urine output. The overall goals of diuretic therapy for each degree of volume overload are defined in Table 114. Further studies are indicated to determine the extent of benefit imparted upon patients by this protocol, and to determine precise goals for diuretic therapy.
Ultrasound provides a non-invasive, reliable method of monitoring a patient's volume status and subsequently augmenting their fluid removal therapy by allowing for real-time evaluation of lung parenchyma and IVC caliber. The current clinically-based methods used to guide this treatment are imprecise. The Reverse- FALLS protocol, named because it is a guide for the removal of fluid rather than a guide for fluid administration as seen in the FALLS protocol, is proposed as a more precise guide for the management of pulmonary edema. Implementation of the lung and IVC ultrasound techniques described in the Reverse-FALLS protocol into standard practices will achieve a level of safe and beneficial diuresis for volume overloaded patients.

Fluid retention is the most common modifiable risk factor for mortality and cardiovascular events in volume overloaded patients1. Fluid retention leads to poorly controlled hypertension, cardiac dysfunction and pulmonary edema, and has been associated with excess mortality in this population. The clinical estimation of a patient's volume status by combining the patient's symptoms, blood pressure, and weight changes represent a clinical assessment that is prone to imprecision2. This article proposes a protocol that utilizes bedside ultrasound (US) techniques to guide the effective management of pulmonary edema. Chest and inferior vena cava (IVC) US form the cornerstone of this proposed clinical protocol for fluid removal. Both Chest and IVC US have a long track record in the literature for a spectrum of applications including the management of acute respiratory failure, end-stage renal disease (ESRD), and circulatory shock. 
Chest US has been shown to provide objective data for the assessment of pulmonary edema in ESRD patients, and accurately reflects the decreasing severity of pulmonary edema as dialysis goes on3. Similarly, US of the inferior vena cava (IVC) has long been utilized for various clinical applications. IVC US is recommend as a routine component of transthoracic echocardiographic examination and serves several purposes, including for the estimation of right atrial pressure (RAP) that is a mark of volume status and pre- load to the heart4. Several studies have elucidated a correlation between IVC caliber and fluid responsivity in shock states5,6. Also notable in the management of shock states, chest ultrasound has been used to detect the onset of new pulmonary edema during fluid resuscitation in circulatory shock, commonly by way of a bedside US application referred to as the Fluid Administration Limited by Lung Sonography (FALLS) protocol7,8. The protocol proposed here, named the Reverse-FALLS protocol, combines well-documented features of chest and IVC ultrasound for the safe and effective management of pulmonary edema. 
Portable, or bedside, US is an imaging modality that offers immediate and reliable data that reduces exposure to radiation, eliminates the need for patient transport, and reduces resource utilization. Due to its availability and the essential absence of associated adverse effects, bedside US can be repeated to monitor and tailor diuretic therapy. Finally, bedside US is easy for clinicians to perform and interpret in real-time9. 
Chest US is a widely-accepted technique that detects specific artifact patterns that represent various pleural and parenchymal pathologies. For instance, "A-lines" are horizontal hyperechoic (bright) reverberation artifacts of the pleural surface and they indicate normal parenchyma that is free of fluid. Alternatively, "B-lines" are hyperechoic vertical artifacts that begin at the inferior aspect of the pleural line and extend to the end of the screen, moving synchronously with respiration. The presence of B-lines in the setting of suspected volume overload indicates extravascular lung water. These B-lines characteristically dissipate during diuresis in a manner that corresponds to volume removal leading to the re-emergence of the dry A-line artifact pattern3. Studies indicate that these US findings are closely associated with elevated pulmonary filling pressures, as assessed by invasive methods10. 
US may also be used to measure the IVC vessel diameter and collapsibility index, which is the percentage of diameter reduction during spontaneous breathing. Several studies have shown a correlation between IVC measurements and volume changes during diuresis, demonstrating the feasibility and applicability of this tool for patients with pulmonary edema11. 
Here, we propose a sample US protocol, the Reverse-FALLS protocol, which integrates both lung and IVC US to guide fluid removal therapy in patients with pulmonary edema.

<table><tbody><tr><td>Portable Ultrasound machine&amp;nbsp;</td><td>Shown in video: FUGIFILM/Sonosite</td><td>Shown in video:&amp;nbsp; M- Turbo</td><td>Any portable ultrasound machine with the following capabilities&lt;br/&gt; &amp;bull;&amp;nbsp; B- Mode&lt;br/&gt; &amp;bull;&amp;nbsp; M- Mode&lt;br/&gt; &amp;bull;&amp;nbsp; Caliper measurement tool</td></tr><tr><td>Transducer</td><td>Shown in video: FUGIFILM/Sonosite</td><td>Shown in video:&amp;nbsp; P21</td><td>Any ultrasound transducer probe with the following capabilities:&lt;br/&gt; &amp;bull;&amp;nbsp; Phased Array&lt;br/&gt; &amp;bull;&amp;nbsp; Low frequency (1-5MHz)</td></tr></tbody></table>

bedside ultrasound for guiding fluid removal in patients with pulmonary edema: the reverse-falls protocol

Fluid retention is the most common risk factor for mortality and cardiovascular complications in patients with volume-overloaded disease states. The extent of diuresis or fluid removal is frequently determined by physical examination which is subject to inaccuracies.
Bedside ultrasound (US) is a portable tool that brings real-time diagnostic imaging to the patient's bedside. This versatile modality makes it possible for the clinician to investigate patients' extravascular and intravascular volume states. The extravascular volume, particularly in the case of pulmonary edema, can be quantitatively assessed by US of the anterior chest. Intravascular volume is estimated by visualizing the inferior vena cava (IVC) caliber. Taken together, the degree of extravascular lung water and the IVC caliber provide objective data that can guide the clinician to determine the level of diuresis needed to effectively yet safely treat pulmonary edema. 
The objective of this article is threefold: 1) to summarize the findings of previous studies on the efficacy of portable US to guide fluid management, 2) to describe a proposed ultrasound protocol to help guide fluid management, and 3) to elucidate techniques that address the measurement of intravascular and extravascular volumes using portable US.

Lung ultrasound estimates the amount of fluid in the extravascular compartment by visualizing A-line or B-line artifacts, as illustrated in Figure 1. The quantity of B-lines on lung ultrasound helps determine the amount of fluid removal required as illustrated in Figure 2. A mixed A-line and B-line pattern, or an A-line predominant pattern suggests lung parenchyma that is relatively free from extra fluid. Mild diuresis may be necessary for complete resolution of extravascular lung water. A B-line predominant pattern suggests the presence excess extravascular lung water. Moderate to aggressive fluid removal therapy may be necessary for complete resolution with level of diuresis based on the number of B-lines present.
IVC ultrasound estimates the amount of fluid in the intravascular compartment by measuring vessel diameter and observing the degree of collapsibility during the respiratory cycle, as illustrated in Figure 3. A maximum diameter (Dmax) of &#60;1.0 may predict hemodynamic compromise. Do not employ aggressive diuresis in this setting as it may induce hypotension in patients with intravascular volume depletion and may potentially cause early discontinuation of diuretic therapy. Alternatively, a large (minimum diameter [Dmin] &#62;2.1 cm), noncompliant IVC with little respiratory variation indicates a volume overloaded state. In combination with a predominant B-line pattern, an aggressive approach to diuretic therapy should be initiated.
The combination of lung and IVC ultrasound provides objective data for assessing the patient&#39;s overall fluid status. Taken together, lung and IVC US techniques can be applied, as proposed in the Reverse-FALLS protocol, to determine the need for diuresis and predict whether the patient can tolerate fluid removal, as illustrated in Figure 4.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57631/57631fig1.jpg" /> 
Figure 1. The extravascular compartment: assessment of lung parenchyma. With the patient in supine or semi-recumbent position, use a phased array, low-frequency probe placed on the anterior chest with probe marker facing cephalad. Select the appropriate machine setting (abdomen or lung) with the screen marker operator-left, and adjust the depth to 8-12 cm. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57631/57631fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57631/57631fig2.jpg" /> 
Figure 2. Gradation of pulmonary edema: setting volume goals. The number of B-lines corresponds to the degree of pulmonary edema: up to 1 B-line is normal, 2-3 B-lines represent mild pulmonary edema, and 4 or more B-lines represent moderate to severe pulmonary edema. A whiteout pattern with no A-lines suggests very severe pulmonary edema. The degree of pulmonary edema will guide the level of diuresis necessary for resolution of volume overloaded state.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57631/57631fig3v2.jpg" /> 
Figure 3.The intravascular compartment: assessment of the IVC. With the patient in a supine or semi-recumbent position, use a phased array, low-frequency probe placed on the anterior chest, just right lateral to the midline with probe marker facing cephalad. Select the cardiac machine setting, with the screen marker operator-right. Adjust the depth to 12-21 cm for optimal image resolution.&#160;
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57631/57631fig4.jpg" /> 
Figure 4. Summary of protocol: utilizing chest and IVC ultrasound to guide fluid management.&#160;
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Level of Diuresis Needed</td>
			<td>Net Negative Fluid Balance per 24 hours</td>
		</tr>
		<tr>
			<td>Mild</td>
			<td>0.5-1.0 liters</td>
		</tr>
		<tr>
			<td>Moderate</td>
			<td>1.0-5.0 liters</td>
		</tr>
		<tr>
			<td>Aggressive</td>
			<td>Great than 3.0-5.0 liters</td>
		</tr>
		<tr>
			<td colspan="2">*As determined by lung and IVC ultrasound via the Reverse=FALLS protocol</td>
		</tr>
	</tbody>
</table>
Table 1. Goals of Diuretic Therapy Defined

Watch this Scientific Journal Video about Bedside Ultrasound for Guiding Fluid Removal in Patients with Pulmonary Edema: The Reverse-FALLS Protocol at JoVE.com

Bedside Ultrasound for Guiding Fluid Removal in Patients with Pulmonary Edema: The Reverse-FALLS Protocol

We describe an imaging protocol that enables the clinician to visualize, in real-time, the patient&#39;s intravascular and extravascular space volumes and set diuresis and fluid removal parameters accordingly for the safe and efficient treatment of pulmonary edema.

Fluid retention is the most common risk factor for mortality and cardiovascular complications in patients with volume-overloaded disease states. The ...

bedside-ultrasound-for-guiding-fluid-removal-patients-with-pulmonary

Nanyang Technological University

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11.1K Views.  Stony Brook University School of Medicine. We describe an imaging protocol that enables the clinician to visualize, in real-time, the patient's intravascular and extravascular space volumes and set diuresis and fluid removal parameters accordingly for the safe and efficient treatment of pulmonary edema.

Video: Bedside Ultrasound for Guiding Fluid Removal in Patients with Pulmonary Edema: The Reverse-FALLS Protocol

Protocol and Guidelines for Point-of-Care Lung Ultrasound in Diagnosing Neonatal Pulmonary Diseases Based on International Expert Consensus

Ultrasound is a safe bedside imaging tool that obviates the use of ionizing radiation diagnostic procedures. Due to its convenience, the lung ultrasound has received increasing attention from neonatal physicians. Nevertheless, clear reference standards and guideline limits are needed for accurate application of this diagnostic modality. This document aims to summarize expert opinions and to provide precise guidance to help facilitate the use of the lung ultrasound in the diagnosis of neonatal lung diseases.

Lung ultrasound is a noninvasive and valuable tool for bedside evaluation of neonatal lung diseases. However, a relative lack of reference standards, protocols and guidelines may limit its application. Here, we aim to develop a standardized neonatal lung ultrasound diagnostic protocol to be used in clinical decision-making.

Ultrasound is a safe bedside imaging tool that obviates the use of ionizing radiation diagnostic procedures. Due to its convenience, the lung ultrasound ...

Ultrasonographic Assessment During Cardiopulmonary Resuscitation

The US-CAB (Ultrasound, Circulation/Airway/Breathing) protocol integrates several sonographic techniques into a structured assessment of the circulation, airway, and breathing status of a patient during cardiopulmonary resuscitation (CPR) in an advanced life support-compliant manner. US-C provides a subxiphoid view of the heart, to look for potentially reversible causes of disease, such as pericardial effusion, pulmonary embolism, hypovolemia, and acute coronary thrombosis. Sonographic cardiac activity during CPR not only helps differentiate pseudo-pulseless electrical activity (PEA) from true PEA but also represents a higher chance of the return of spontaneous circulation (ROSC) and survival. Evaluation of the inferior vena cava (IVC) shows the fluid status of the patient and indicates the best methods to use for fluid resuscitation. If aortic dissection is suspected, a subxiphoid view of the aorta is suggested for identifying an intimal flap. Once intubation is done, tracheal ultrasound (US-A) at the suprasternal notch helps differentiate endotracheal intubation (one air-mucosal interface with one comet-tail) from esophageal intubation (double tract sign). Immediately following US-A, bilateral lung US (US-B) should be done to confirm proper bilateral ventilation using the lung sliding sign. In addition, US-C can be serially followed to see the dynamic changes in the cardiac chambers and IVC, or any cardiac contraction suggestive of ROSC. US-B can also detect coexisting lung or pleural pathologies without interfering with the performance of CPR. The main concern when implementing this method is maintaining high-quality CPR without delays in chest compressions when performing US-CAB. Rigorous training and continued practice are key to minimize any interruptions during resuscitation.

Here, we present a US-CAB (Ultrasound, Circulation/Airway/Breathing) protocol for use during cardiopulmonary resuscitation (CPR). US-C evaluates the subxiphoid view of the heart and inferior vena cava. After intubation, tracheal US (US-A) and lung US (US-B) help confirm endotracheal intubation and proper ventilation.

The US-CAB (Ultrasound, Circulation/Airway/Breathing) protocol integrates several sonographic techniques into a structured assessment of the circulation, ...

Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure and death in critically ill patients, and there is an urgent need to find effective therapies. Preclinical studies have shown that inhaled halogenated agents may have beneficial effects in animal models of ARDS. The development of new devices to administer halogenated agents using modern intensive care unit (ICU) ventilators has significantly simplified the dispensing of halogenated agents to ICU patients. Because previous experimental and clinical research suggested potential benefits of halogenated volatiles, such as sevoflurane or isoflurane, for lung alveolar epithelial injury and inflammation, two pathophysiologic landmarks of diffuse alveolar damage during ARDS, we designed an animal model to understand the mechanisms of the effects of halogenated agents on lung injury and repair. After general anesthesia, tracheal intubation, and the initiation of mechanical ventilation, ARDS was induced in piglets via the intratracheal instillation of hydrochloric acid. Then, the piglets were sedated with inhaled sevoflurane or isoflurane using an ICU-type device, and the animals were ventilated with lung-protective mechanical ventilation during a 4 h period. During the study period, blood and alveolar samples were collected to evaluate arterial oxygenation, the permeability of the alveolar-capillary membrane, alveolar fluid clearance, and lung inflammation. Mechanical ventilation parameters were also collected throughout the experiment. Although this model induced a marked decrease in arterial oxygenation with altered alveolar-capillary permeability, it is reproducible and is characterized by a rapid onset, good stability over time, and no fatal complications.
We have developed a piglet model of acid aspiration that reproduces most of the physiological, biological, and pathological features of clinical ARDS, and it will be helpful to further our understanding of the potential lung-protective effects of halogenated agents delivered through devices used for inhaled ICU sedation.

We describe a model of hydrochloric acid-induced acute respiratory distress syndrome (ARDS) in piglets receiving sedation with halogenated agents, isoflurane and sevoflurane, through a device used for inhaled intensive care sedation. This model can be used to investigate the biological mechanisms of halogenated agents on lung injury and repair.

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure and death in critically ill patients, and there is an urgent ...

Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge

A preload challenge (PC) is a clinical maneuver that, first, increases the cardiac filling (i.e., preload) and, second, calculates the change in cardiac output. Fundamentally, a PC is a bedside approach for testing the Frank-Starling-Sarnoff (i.e., "cardiac function") curve. Normally, this curve has a steep slope such that a small change in the cardiac preload generates a large change in the stroke volume (SV) or cardiac output. However, in various disease states, the slope of this relationship flattens such that increasing the volume into the heart leads to little rise in the SV. In this pathological scenario, additional cardiac preload (e.g., intravenous fluid) is unlikely to be physiologically effective and could lead to harm if organ congestion evolves. Therefore, inferring both the cardiac preload and output is clinically useful as it may guide intravenous (IV) fluid resuscitation. Accordingly, the goal of this protocol is to describe a method for contemporaneously tracking the surrogates of cardiac preload and output using a novel, wireless, wearable ultrasound during a well-validated preload challenge.

The Frank-Starling-Sarnoff curve is clinically important and describes the relationship between cardiac preload and output. This report illustrates a novel method of simultaneous jugular venous and carotid arterial Doppler velocimetry as transient surrogates of cardiac preload and output, respectively; this approach is enabled by wireless, wearable Doppler ultrasound.

A preload challenge (PC) is a clinical maneuver that, first, increases the cardiac filling (i.e., preload) and, second, calculates the change in cardiac ...

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.

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 ...

Point-of-Care Lung Ultrasound in Adults: Image Acquisition

Consultative ultrasound performed by radiologists has traditionally not been used for imaging the lungs, as the lungs&#39; air-filled nature normally prevents direct visualization of the lung parenchyma. When showing the lung parenchyma, ultrasound typically generates a number of non-anatomic artifacts. However, over the past several decades, these artifacts have been studied by diagnostic point-of-care ultrasound (POCUS) practitioners, who have identified findings that have value in narrowing the differential diagnoses of cardiopulmonary dysfunction. For instance, in patients presenting with dyspnea, lung POCUS is superior to chest radiography (CXR) for the diagnosis of pneumothorax, pulmonary edema, lung consolidations, and pleural effusions. Despite its known diagnostic value, the utilization of lung POCUS in clinical medicine remains variable, in part because training in this modality across hospitals remains inconsistent. To address this educational gap, this narrative review describes lung POCUS image acquisition in adults, including patient positioning, transducer selection, probe placement, acquisition sequence, and image optimization.

Point-of-care ultrasound (POCUS) of the lungs provides quick answers in rapidly changing clinical scenarios. We present an efficient and informative protocol for image acquisition for use in acute care settings.

Consultative ultrasound performed by radiologists has traditionally not been used for imaging the lungs, as the lungs&#39; air-filled nature normally ...

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 ...

POCUS Protocol for IVC Assessment in Management of Heart Failure

Workflow and Framework for Collecting and Implementing Point-of-Care Ultrasound Data in the Management of Heart Failure Patients

Management and prevention of acute decompensated heart failure remain highly prevalent and challenging medical conditions. Incorporation of Point-of-Care Ultrasound (POCUS) as an adjunctive tool for assessing volume status and treatment response has shown significant promise. POCUS can be used for imaging internal anatomic structures serially and capturing these images for comparison and measurement over time. This protocol describes a scalable and standardized methodology for the serial assessment of the inferior vena cava (IVC). The methodology includes serial image collection, measurement, and presentation in the electronic medical record. A workflow for POCUS-acquired images of the IVC was created to capture the images and measure the diameter in a discrete data field for direct comparison over time and in response to clinical management. The protocol also includes the assessment of the presence or absence of pleural effusion as discrete data in the standardized workflow. By integrating POCUS into heart failure management, clinicians can improve patient outcomes through more precise and timely adjustments in treatment.

Author Spotlight: Workflow for Integrating POCUS Data into EHR for Managing Heart Failure Patients

This protocol presents a scalable workflow for the use of point-of-care ultrasound in the management of hospitalized and outpatient heart failure patients.

Management and prevention of acute decompensated heart failure remain highly prevalent and challenging medical conditions. Incorporation of Point-of-Care ...

A Porcine Model of Acute Autologous Pulmonary Embolism

Acute pulmonary embolism (PE) is a potentially life-threatening condition that causes abrupt obstruction of the pulmonary arteries, leading to acute right heart failure. Novel diagnostic methods and catheter-directed therapies are being developed rapidly, and there is an obvious need for a realistic PE animal model that can be used for pathophysiological evaluation and preclinical testing.
This protocol introduces a porcine model employing large autologous pulmonary emboli. Instrumentations are performed with minimally invasive techniques, creating a close-chest model that enables the investigation of various treatment options with high reproducibility. Three hours after drawing blood to create autologous emboli ex vivo, the induction of PE caused an immediate increase in the mean pulmonary arterial pressure (17&#160;&#177; 3 mmHg to 33&#160;&#177; 6 mmHg, p &#60; 0.0001) and heart rate (50&#160;&#177; 9 beats&#183;min-1 to 63&#160;&#177; 6 beats&#183;min-1,&#160;p &#60; 0.0003) accompanied by a decreased cardiac output (5.0&#160;&#177; 0.8 L/min to 4.5&#160;&#177; 0.9 L/min, p &#60; 0.037) compared to baseline. The CT pulmonary angiography revealed multiple emboli, and the pulmonary obstruction percentage was increased compared to baseline (0% [0-0] to 57.1% [38.8-63.3], p &#60; 0.0001). In the acute phase, the phenotype is comparable to intermediate-risk PE.
The model represents a realistic and well-characterized phenotype of intermediate-risk PE and creates an opportunity to test novel diagnostic methods, interventional and pharmaceutical treatments, and hands-on training for healthcare workers in interventional procedures.

This study presents a porcine model of pulmonary embolism (PE) using large autologous emboli that replicate acute intermediate-risk PE. The model is well-suited for the evaluation of both pathophysiology and treatment responses.

Acute pulmonary embolism (PE) is a potentially life-threatening condition that causes abrupt obstruction of the pulmonary arteries, leading to acute right ...

Point-of-Care Ultrasound for Peripheral Veno-Arterial Extracorporeal Membrane Oxygenation Without Left Ventricular Venting

Over the past several decades, veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has become a critical tool in the management of patients with severe cardiogenic shock and cardiopulmonary failure. Due to the inherent instability of these patients, their transport away from intensive care units is fraught with risk. As a result, bedside diagnostic tools are essential for their daily care. One such tool is point-of-care ultrasound (POCUS) of the heart, which can non-invasively assess several parameters: left ventricular (LV) performance (size, systolic function, stroke volume, aortic valve opening), right ventricular (RV) performance (size, systolic function), and the presence of intracardiac thrombus. Additionally, POCUS can assist in evaluating readiness for V-A ECMO weaning and eventual decannulation. Despite its potential, the use of POCUS in the context of V-A ECMO remains inconsistent due to variability in provider training. This study aims to address this gap by detailing POCUS image acquisition in V-A ECMO, particularly in the absence of LV venting. It covers key aspects such as patient positioning, transducer selection, probe placement, acquisition sequence, and image optimization.

This protocol outlines the use of point-of-care ultrasound (POCUS) to monitor patients on peripheral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) without left ventricular venting. It evaluates left ventricular distension, intracardiac or aortic root thrombus, and identifies useful cardiac POCUS parameters for weaning from V-A ECMO.

Over the past several decades, veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has become a critical tool in the management of patients with ...