The authors have no acknowledgments.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the Duke University Health System institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The protocol was performed using inputs from the following publications3,10. Images were performed on the authors themselves for normal images and as part of routine educational ultrasound scans done for teaching purposes for positive images, with preceding verbal consent as per institutional standards. The patients were selected based on the following criteria: inclusion criteria: any patient with lower extremity pain, swelling, or other clinical reason to suspect DVT; exclusion criteria: patients with a lower extremity amputation who may be missing the popliteal or distal femoral views.
1. Transducer selection
<ol>
	<li>Select the high-frequency linear transducer (5-13 MHz) for the DVT scan to ensure a high-resolution image of the veins. 
	&#8203;NOTE: In obese patients or, occasionally, for the popliteal vein, DVT scanning with a low-frequency curvilinear (2-5 MHz) transducer is necessary to have adequate penetration and depth. However, patients challenging enough to require a low-frequency transducer generally fall outside the scope of point-of-care ultrasound training and usually warrant a comprehensive radiology ultrasound.</li>
</ol>
2. Machine settings
<ol>
	<li>Setting the depth, gain, and focus
	<ol>
		<li>Set the depth so that the target vessels appear in the middle 1/3 of the ultrasound screen by pressing the up or down depth button (between 3-6 cm).</li>
		<li>Set the gain so that the vessels contain a few spots of grey but are otherwise black by pressing the right or left gain buttons (MIS between 0.6-0.8, TIS 0.1).</li>
		<li>If the machine has the capability, aim the focus beam at or slightly below the level of the target vessels by clicking the box on the screen and moving it while holding down the button, and then release.</li>
	</ol>
	</li>
	<li>Set the machine mode. Click on B-Mode, which is a 2-dimensional (2D) greyscale ultrasound exam. Use B-mode to obtain both the non-compressed and compressed images. 
	NOTE: If the B-mode images are ambiguous, providers trained in color and spectral Doppler can consider adding these techniques, but they are not classically included in lower extremity POCUS DVT protocols.</li>
	<li>For optimal scanning ergonomics, place the machine with the ultrasound screen in direct line of sight with the ultrasound probe.</li>
</ol>
3. Patient position
<ol>
	<li>Before scanning, expose the patient&#39;s entire leg from the groin to the knee.</li>
	<li>Place the patient in the supine position as this is the ideal view for DVT examination of the common femoral and femoral veins. Place the patient in the frog-leg position (external rotation at the hip with knees slightly bent) to enable better visualization and scanning of the distal veins. 
	&#8203;NOTE: The popliteal veins can also be assessed with either a frog-leg position or with slight flexion of the knee. Although lateral decubitus and prone positioning might improve visualization (particularly for patients with a higher body mass index), they may not be feasible in all situations (e.g., in critically ill patients or intra-operatively).</li>
</ol>
4. B-mode scanning
<ol>
	<li>Groin and thigh: Apply gel to the patient&#39;s skin in a linear path that traces out the expected path of the ultrasound transducer to increase the efficiency of motion for performing the examination of this part.</li>
	<li>Knee: Apply gel to the transducer itself, as a generous application of gel will facilitate the scanning efficiency.</li>
	<li>Transducer orientation: Place the transducer in a transverse position with the orientation marker directed toward the patient&#39;s right side to ensure that images captured during scanning correspond to the anatomical direction of the structures.</li>
	<li>Place the probe perpendicular to the path of the vein to visualize the vein in a short-axis view. Center the venous structure on the screen. Add long-axis imaging in ambiguous cases by rotating the probe 90&#176; so that the marker points toward the patient&#39;s head.</li>
</ol>
5. Scanning and compression technique
<ol>
	<li>Compression sequence: Begin scanning immediately caudal to the inguinal crease, progress distally sequentially with downward compression, and then release at each point as shown in Figure 13,10.
	<ol>
		<li>Compress such that the entire vein collapses, with the anterior wall touching the posterior wall, while the artery remains pulsatile. Do not apply resting surface pressure between each compression as it can obscure the visualization of the veins. The vein should collapse fully when enough pressure is applied with the transducer to indent an adjacent artery.</li>
	</ol>
	</li>
	<li>Click Save Clip and compress and then release at the common femoral vein (CFV) and femoral artery (FA) just below the inguinal ligament.</li>
	<li>Slide the probe distally about 1 cm and record the same compression and release technique at the CFV and FA at the intake of the great saphenous vein (GSV).</li>
	<li>Click Save Clip, then compress, and release the probe at the CFV at the bifurcation of the FA into the superficial femoral artery (SFA) and deep femoral artery (DFA). Between the SFA and DFA, there will typically be a lateral perforator vein draining from lateral-to-medial into the CFV. Ensure that both the lateral perforator vein and GSV are compressible. 
	NOTE: Though these are superficial veins, clots in these locations have the potential to embolize, resulting in the same life-threatening complications as caused by DVTs.</li>
	<li>Click Save Clip, then compress, and release the probe at the CFV at the bifurcation of the CFV into the femoral vein (FV) and deep femoral vein (DFV).</li>
	<li>Click Save Clip, then compress, and release the probe at the CFV at the popliteal vein behind the knee.</li>
	<li>Once points 1-5 (as in Figure 1) are all fully compressible, scan the FV along the thigh from proximal to distal until the vein disappears in the adductor canal. During this scanning process, attempt to compress the vein approximately every 1-2 cm.</li>
</ol>

<ol>
	<li>Beckman, M. 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=Venous+thromboembolism:+A+public+health+concern.">Venous thromboembolism: A public health concern.</a> American Journal of Preventive Medicine. 38, 495-501 (2010).</li><li>Kearon, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+history+of+venous+thromboembolism.">Natural history of venous thromboembolism.</a> Circulation. 107 (23), 22-30 (2003).</li><li>Schafer, J. M., Stickles, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonoguide:+Ultrasound+guide+for+emergency+physicians.">Sonoguide: Ultrasound guide for emergency physicians.</a> American College of Emergency Physicians. , (2020).</li><li>Pomero, F., 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=Accuracy+of+emergency+physician-performed+ultrasonography+in+the+diagnosis+of+deep-vein+thrombosis:+A+systematic+review+and+meta-analysis.">Accuracy of emergency physician-performed ultrasonography in the diagnosis of deep-vein thrombosis: A systematic review and meta-analysis.</a> Thrombosis and Haemostasis. 109 (1), 137-145 (2013).</li><li>Theodoro, 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=Real-time+B-mode+ultrasound+in+the+ED+saves+time+in+the+diagnosis+of+deep+vein+thrombosis+(DVT).">Real-time B-mode ultrasound in the ED saves time in the diagnosis of deep vein thrombosis (DVT).</a> American Journal of Emergency Medicine. 22 (3), 197-200 (2004).</li><li>Burnside, P. R., Brown, M. D., Kline, 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=Systematic+review+of+emergency+physician-performed+ultrasonography+for+lower-extremity+deep+vein+thrombosis.">Systematic review of emergency physician-performed ultrasonography for lower-extremity deep vein thrombosis.</a> Academic Emergency Medicine. 15 (6), 493-498 (2008).</li><li>Adhikari, 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=Isolated+deep+venous+thrombosis:+Implications+for+2-point+compression+ultrasonography+of+the+lower+extremity.">Isolated deep venous thrombosis: Implications for 2-point compression ultrasonography of the lower extremity.</a> Annals of Emergency Medicine. 66 (3), 262-266 (2015).</li><li>Cogo, 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=Distribution+of+thrombosis+in+patients+with+symptomatic+deep+vein+thrombosis.+Implications+for+simplifying+the+diagnostic+process+with+compression+ultrasound.">Distribution of thrombosis in patients with symptomatic deep vein thrombosis. Implications for simplifying the diagnostic process with compression ultrasound.</a> Archives of Internal Medicine. 153 (24), 2777-2780 (1993).</li><li>Badgett, D. K., 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=Duplex+venous+imaging:+Role+for+a+comprehensive+lower+extremity+examination.">Duplex venous imaging: Role for a comprehensive lower extremity examination.</a> Annals of Vascular Surgery. 14 (1), 73-76 (2000).</li><li>Kory, P. 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=Accuracy+of+ultrasonography+performed+by+critical+care+physicians+for+the+diagnosis+of+DVT.">Accuracy of ultrasonography performed by critical care physicians for the diagnosis of DVT.</a> Chest. 139 (3), 538-542 (2011).</li><li>Bates, S. 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=Diagnosis+of+DVT:+Antithrombotic+therapy+and+prevention+of+thrombosis,+9th+ed:+American+College+of+Chest+Physicians+Evidence-Based+Clinical+Practice+Guidelines.">Diagnosis of DVT: Antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.</a> Chest. 141 (2), 3512 (2012).</li><li>Wolf, S. J., 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+College+of+Emergency+Physicians+Clinical+Policies+Subcommittee+(Writing+Committee)+on+Thromboembolic+Disease.+Clinical+policy:+Critical+issues+in+the+evaluation+and+management+of+adult+patients+presenting+to+the+emergency+department+with+suspected+acute+venous+thromboembolic+disease.">American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Thromboembolic Disease. Clinical policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected acute venous thromboembolic disease.</a> Annals of Emergency Medicine. 71 (5), 59-109 (2018).</li><li>Elliott, C. G., Goldhaber, S. Z., Jensen, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delays+in+diagnosis+of+deep+vein+thrombosis+and+pulmonary+embolism.">Delays in diagnosis of deep vein thrombosis and pulmonary embolism.</a> Chest. 128 (5), 3372-3376 (2005).</li><li>Musil, D., Kovacik, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delay+between+clinical+presentation+and+treatment+of+deep+venous+thrombosis+in+the+lower+limbs+and+regression+of+thrombosis.">Delay between clinical presentation and treatment of deep venous thrombosis in the lower limbs and regression of thrombosis.</a> Phlebology. 37 (2), 120-124 (2022).</li><li>Laursen, C. B., 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=Focused+sonography+of+the+heart,+lungs,+and+deep+veins+identifies+missed+life-threatening+conditions+in+admitted+patients+with+acute+respiratory+symptoms.">Focused sonography of the heart, lungs, and deep veins identifies missed life-threatening conditions in admitted patients with acute respiratory symptoms.</a> Chest. 144 (6), 1868-1875 (2013).</li><li>Barosse-Antle, M. E., Patel, K. H., Kramer, J. A., Baston, C. M. <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+ultrasound+for+bedside+diagnosis+of+lower+extremity+DVT.">Point-of-care ultrasound for bedside diagnosis of lower extremity DVT.</a> Chest. 160 (5), 1853-1863 (2021).</li><li>Frankel, H. 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=Guidelines+for+the+appropriate+use+of+bedside+general+and+cardiac+ultrasonography+in+the+evaluation+of+critically+ill+patients-Part+I:+General+ultrasonography.">Guidelines for the appropriate use of bedside general and cardiac ultrasonography in the evaluation of critically ill patients-Part I: General ultrasonography.</a> Critical Care Medicine. 43 (11), 2479-2502 (2015).</li><li>Bernardi, E., Camporese, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+of+deep-vein+thrombosis.">Diagnosis of deep-vein thrombosis.</a> Thrombosis Research. 163, 201-206 (2018).</li><li>Caronia, J., 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=Resident+performed+two-point+compression+ultrasound+is+inadequate+for+diagnosis+of+deep+vein+thrombosis+in+the+critically+ill.">Resident performed two-point compression ultrasound is inadequate for diagnosis of deep vein thrombosis in the critically ill.</a> Journal of Thrombosis and Thrombolysis. 37 (3), 298-302 (2014).</li></ol>

Robert Jones is an educational material writer for&#160;www.emsono.com. All the other authors have nothing to disclose.

Venous thromboembolism is a common disease, affecting approximately 300,000-600,000 people in the United States annually, with serious complications including pulmonary embolism. Mortality rates in these patients range from 10%-30%2,3,4. Studies have consistently found significant delays in the diagnosis of DVT, with one prospective study of 1,152 patients across 70 medical centers identifying a delay of greater than 1 week in 2...

Deep venous thrombosis (DVT) is the formation of a thrombus in the deep peripheral veins of the extremities. It is a common and important finding, affecting about 300,000-600,000 people in the United States annually1. The propagation of DVT into a pulmonary embolism can occur in 10%-50% of patients and can be deadly, with a mortality rate of 10%-30%, which is higher than the in-hospital mortality for myocardial infarction1,2,3. The risk factors for thrombus formation include hypercoagulable states from genetic factors (family history of DVT, factor V Leiden, protein C or S deficiency), acquired factors (older age, malignancy, obesity, antiphospholipid antibodies, and others), and situational factors (pregnancy, oral contraceptives, recent surgery, travel, trauma, or prolonged immobilization, including from hospitalizations)1.
Early diagnosis of DVT in critically ill patients can expedite patient care and potentially prevent life-threatening complications such as pulmonary embolism, pulmonary infarct, and cardiac involvement1,2,3. A systematic review by Pomero et al. showed a pooled prevalence of 23.1% for DVT in critically ill patients4. Screening for lower extremity DVT has traditionally been performed by radiology ultrasound technicians conducting comprehensive whole-leg duplex exams including both grayscale compression ultrasound and color/spectral Doppler. However, several smaller or community clinical sites lack the direct availability of a sonographer during certain times of the day, such as on nights or weekends, thus creating a delay in patient care5. More recently, acute care providers have devised methods of screening for proximal lower extremity DVTs using point-of-care ultrasound (POCUS)-focused imaging protocols, which demonstrate similarly high sensitivity and specificity in critically ill patients3,4,6. Proximal lower extremity DVTs are defined as DVTs occurring anywhere in the groin, thigh, or knee within the femoral or popliteal venous system. Falling outside of this category are DVTs in the following locations: calf veins (where DVTs are of uncertain clinical significance) and pelvic veins (i.e., the common, external, and internal iliac veins), which are only detectable indirectly using the color and spectral Doppler portion of consultative lower extremity venous ultrasound exams2,3.
Understanding the typical anatomic distribution of DVTs makes performing these bedside exams rapid and easy. First, 70%-99% of proximal lower extremity DVTs involve the femoral or popliteal regions7,8,9. Second, grayscale compression ultrasound is a simple and accurate method for evaluating DVTs; when enough pressure is applied to indent an adjacent artery, normal veins should collapse fully, whereas veins harboring a DVT will not. Combining these principles, the two-zone or three-zone lower extremity DVT POCUS examinations center on compression ultrasound of veins in the inguinal, thigh, and popliteal areas. These techniques have been clinically validated in prior intensive care and emergency medicine studies, demonstrating high sensitivity (96.1%, with a 95% confidence interval (CI) of 90.6%-98.5%) and specificity (96.8%, with a 95% CI of 94.6%-98.1%), with high overall diagnostic accuracy (95%)3,4,6. However, in the experience of the authors, the DVT POCUS exam remains grossly underutilized in the care of critically ill patients, possibly because clinicians are not familiar with the image acquisition sequence. This narrative review with associated visual aids describes an image acquisition protocol for performing a POCUS exam to screen for proximal lower extremity DVTs to assist providers in proper expedited image acquisition during clinical care.

<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 normal images/clips</td>
		</tr>
		<tr>
			<td>SPARQ ultrasound machine</td>
			<td>Philips</td>
			<td>n/a</td>
			<td>Used to obtain abnormal images/clips</td>
		</tr>
	</tbody>
</table>

point-of-care ultrasound screening for proximal lower extremity deep venous thrombosis

Acute lower extremity deep venous thrombosis (DVT) is a serious vascular disorder that requires accurate and early diagnosis to prevent life-threatening sequelae. While whole leg compression ultrasound with color and spectral Doppler is commonly performed in radiology and vascular labs, point-of-care ultrasound (POCUS) is becoming more common in the acute care setting. Providers appropriately trained in focused POCUS can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. This paper describes a simplified yet validated approach to POCUS by describing a three-zone protocol for lower extremity DVT POCUS image acquisition. The protocol explains the steps in obtaining vascular images at six compression points in the lower extremity. Beginning at the level of the proximal thigh and moving distally to the popliteal space, the protocol guides the user through each of the compression points in a stepwise manner: from the common femoral vein to the femoral and deep femoral vein bifurcation, and, finally, to the popliteal vein. Further, a visual aid is provided that may assist providers during real-time image acquisition. The goal in presenting this protocol is to help make proximal lower extremity DVT exams more accessible and efficient for POCUS users at the patient&#39;s bedside.

We describe the interpretation of proximal lower extremity DVT POCUS in patients with an initial suspected DVT.
The attached Figure 2 demonstrates negative POCUS ultrasound images for DVT in the left and right lower extremities, with multi-point compression from the proximal to distal veins as demonstrated in Figure 1 (from thigh to knee). In a negative DVT study, the veins are completely collapsible, with the anterior wall touching t...

Watch this Scientific Journal Video about Point-Of-Care Ultrasound Screening for Proximal Lower Extremity Deep Venous Thrombosis at JoVE.com

Point-Of-Care Ultrasound Screening for Proximal Lower Extremity Deep Venous Thrombosis

Traditionally, lower extremity deep venous thrombosis (DVT) is diagnosed by radiology-performed venous duplex ultrasound. Providers appropriately trained in focused point-of-care ultrasound (POCUS) can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. We describe the scanning technique for focused POCUS DVT lower extremity examination.

Acute lower extremity deep venous thrombosis (DVT) is a serious vascular disorder that requires accurate and early diagnosis to prevent life-threatening ...

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11.8K Views.  Duke University School of Medicine. Traditionally, lower extremity deep venous thrombosis (DVT) is diagnosed by radiology-performed venous duplex ultrasound. Providers appropriately trained in focused point-of-care ultrasound (POCUS) can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. We describe the scanning technique for focused POCUS DVT lower extremity examination.

Video: Point-Of-Care Ultrasound Screening for Proximal Lower Extremity Deep Venous Thrombosis

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 ...

Point-of-Care Ultrasound: A Review of Ultrasound Parameters for Predicting Difficult Airways

Airway management remains a crucial part of perioperative care. The conventional approach to assessing potentially difficult airways emphasizes the LEMON method, which looks for and evaluates the Mallampati classification, signs of obstruction, and neck mobility. Clinical findings help predict a higher likelihood of difficult tracheal intubation, but no clinical result reliably excludes difficult intubation. Ultrasound as an adjunct to clinical examination can provide the clinician with a dynamic anatomical airway assessment, which is impossible with clinical examination alone. In the hands of anesthesiologists, ultrasound is becoming more popular in the perioperative period. This method is particularly applicable for identifying proper endotracheal tube positioning in specific patient populations, such as those who are morbidly obese and patients with head and neck cancer or trauma. The focus is on identifying the normal anatomy, correctly positioning the endotracheal tube, and refining the parameters that predict difficult intubation. Several ultrasound measurements are clinical indicators of difficult direct laryngoscopy in the literature. A meta-analysis revealed that the distance from the skin to the epiglottis (DSE) is most associated with a difficult laryngoscopy. An ultrasound of the airway could be applied in routine practice as an adjunct to the clinical examination. A full stomach, rapid sequence intubation, gross visual anatomical abnormalities, and restricted neck flexibility prevent using ultrasound to assess the airway. The airway evaluation is performed with a linear array transducer of 12-4 MHz, with the patient in the supine position, with no pillow, and with the head and neck in a neutral position. The central axis of the neck is where the ultrasound parameters are measured. These image acquisitions guide the standard ultrasound examination of the airway.

A point-of-care ultrasound (POCUS) is a simple, non-invasive, and portable tool that enables dynamic airway assessment. Several studies have attempted to determine the role of ultrasound parameters as an adjunct to clinical examination in predicting difficult laryngoscopies.

Airway management remains a crucial part of perioperative care. The conventional approach to assessing potentially difficult airways emphasizes the LEMON ...

Optic Nerve Sheath Point of Care Ultrasound: Image Acquisition

The goal of this protocol is to develop a standardized method for acquiring images of the optic nerve sheath and measuring the optic nerve sheath diameter (ONSD). Diagnostic ultrasound of the ONSD to detect intracranial hypertension has traditionally faced many problems because of methodologic discrepancies. Due to inconsistencies in the measuring techniques, the potential for ONSD to become a non-invasive bedside monitoring tool for ICP has been hampered. However, establishing a transparent, consistent methodology for measuring the ONSD would support its use as a valid and reliable method of identifying intracranial hypertension. This is important as it has both high sensitivity and specificity in acute care settings. This narrative review describes ONSD POCUS image acquisition, including patient positioning, transducer selection, probe placement, the acquisition sequence, and image optimization. Further, visual aids are provided to assist in real-time during image acquisition. This method should be considered for patients for whom there are concerns regarding intracranial hypertension but who do not have an intracranial monitor in place.

Point-of-care ultrasound (POCUS) of the optic nerve sheath diameter (ONSD) has been shown to be useful in identifying patients with increased intracranial pressure (ICP). However, the non-standardized technique for this POCUS has hampered its use. We present a standardized image acquisition protocol for use in the acute care setting.

The goal of this protocol is to develop a standardized method for acquiring images of the optic nerve sheath and measuring the optic nerve sheath diameter ...

Imaging the Abdominal Aorta with Point-of-Care Ultrasound

An Approach to Point-Of-Care Ultrasound Evaluation of the Abdominal Aorta

Disorders of the abdominal aorta, including aneurysms and dissection, have potentially high rates of morbidity and mortality. While computed tomography (CT) is the current gold standard to image the abdominal aorta, the process of obtaining a CT may be time-consuming, requires the use of intravenous contrast dye, and involves exposure to ionizing radiation. Point-of-care Ultrasound (POCUS) can be performed at the bedside and has excellent sensitivity and specificity for the diagnosis of abdominal aortic aneurysm and excellent specificity for the diagnosis of abdominal aortic dissection. Additionally, POCUS is non-invasive, cost-effective, lacks ionizing radiation, requires no intravenous contrast dye, and can be performed without taking the patient from a critical care area. Screening for abdominal aortic aneurysm (AAA) can be done in primary care settings as well. 
This article will review the approach to POCUS of the abdominal aorta to evaluate such critical pathology. In this paper, we will review the sonographic anatomy of the abdominal aorta as well as the choice of the ultrasound probe, description of POCUS image acquisition, and some pearls and pitfalls of using POCUS to aid in the diagnosis of potentially life-threatening abdominal aortic pathology.

Author Spotlight: Using Point-of-Care Ultrasound for Comprehensive Evaluation of the Abdominal Aorta

This protocol reviews the steps to image the abdominal aorta with point-of-care ultrasound. We discuss image acquisition, troubleshooting imaging pitfalls and artifacts, and the recognition of life-threatening abdominal aortic pathology.

Disorders of the abdominal aorta, including aneurysms and dissection, have potentially high rates of morbidity and mortality. While computed tomography ...

Gastric Ultrasound Technique for Mitigating Peri-Procedural Aspiration Risk

Gastric Point of Care Ultrasound in Adults: Image Acquisition and Interpretation

Over the past two decades, diagnostic point-of-care ultrasound (POCUS) has emerged as a rapid and non-invasive bedside tool for addressing clinical inquiries related to gastric content. One emerging concern pertains to patients about to undergo sedation and/or endotracheal intubation: the elevated risk of aspiration from the patient&#39;s stomach contents. Aspiration of gastric contents into the lungs poses a serious and potentially life-threatening complication. This occurs more frequently when the stomach is considered &#34;full&#34; and can be affected by the techniques employed for airway management, making it potentially preventable. To mitigate the risk of peri-procedural aspiration, two distinct medical specialties (anesthesiology and critical care medicine) have independently developed techniques to utilize ultrasonography for identifying patients requiring &#34;full stomach&#34; precautions. Due to these separate specialties, the work of each group remains relatively unfamiliar outside its respective field. This article presents descriptions of both techniques for gastric ultrasound. Furthermore, it explains how these approaches can complement each other when one of them falls short. Regarding image acquisition, the article covers the following topics: indications and contraindications, selection of the appropriate probe, patient positioning, and troubleshooting. The article also delves into image interpretation, complete with example images. Additionally, it demonstrates how one of the two techniques can be employed to estimate gastric fluid volume. Lastly, the article briefly discusses medical decision-making based on the findings of this examination.

Author Spotlight: Point-of-Care Ultrasound for Gastric Content Assessment and Risk Stratification in Perioperative Care 

This protocol introduces two methods for image acquisition in gastric ultrasonography. Additionally, tips are provided for interpreting this information to assist in medical decision-making.

Over the past two decades, diagnostic point-of-care ultrasound (POCUS) has emerged as a rapid and non-invasive bedside tool for addressing clinical ...

Ultrasound in Evaluating Diaphragm Dysfunction and Monitoring Treatment

Measuring Diaphragm Thickness and Function Using Point-of-Care Ultrasound

The diaphragm is the main component of the respiratory muscle pump. Diaphragm dysfunction can cause dyspnea and exercise intolerance, and predisposes affected individuals to respiratory failure. In mechanically ventilated patients, the diaphragm is susceptible to atrophy and dysfunction through disuse and other mechanisms. This contributes to failure to wean and poor long-term clinical outcomes. Point-of-care ultrasound provides a valid and reproducible method for evaluating diaphragm thickness and contractile activity (thickening fraction during inspiration) that can be readily employed by clinicians and researchers alike. This article presents best practices for measuring diaphragm thickness and quantifying diaphragm thickening during tidal breathing or maximal inspiration. Once mastered, this technique can be used to diagnose and prognosticate diaphragm dysfunction, and guide and monitor response to treatment over time in both healthy individuals and acute or chronically ill patients.

Author Spotlight: Unraveling the Impact of Mechanical Ventilation on Diaphragm Function and Patient Outcomes 

Diaphragm thickness and function can be assessed in healthy individuals and critically ill patients using point-of-care ultrasound. This technique offers an accurate, reproducible, feasible, and well-tolerated method for evaluating diaphragm structure and function.

The diaphragm is the main component of the respiratory muscle pump. Diaphragm dysfunction can cause dyspnea and exercise intolerance, and predisposes ...

Probe Selection and Machine Presets for Point-of-Care Ultrasound of the Abdominal Aorta

Advancing Bedside Care: A Multidisciplinary Guide to Kidney-Genitourinary POCUS

Point-of-Care Kidney and Genitourinary Ultrasound in Adults: Image Acquisition

A range of conditions involving the kidneys and urinary bladder can cause organ-threatening complications that are preventable if diagnosed promptly with diagnostic imaging. Common imaging modalities include either computed tomography or diagnostic ultrasound. Traditionally, ultrasound of the kidney-genitourinary system has required consultative teams consisting of a sonographer performing image acquisition and a radiologist performing image interpretation. However, diagnostic point-of-care ultrasound (POCUS) has recently emerged as a useful tool to troubleshoot acute kidney injury at the bedside. Studies have shown that non-radiologists can be trained to perform diagnostic POCUS of the kidneys and bladder with high accuracy for a set number of important conditions. Currently, diagnostic POCUS of the kidney-genitourinary system remains underused in actual clinical practice. This is likely because image acquisition for this organ system is unfamiliar to most clinicians in specialties that encounter acute kidney injury, including primary care, emergency medicine, intensive care, anesthesiology, nephrology, and urology. To address this multi-specialty educational gap, this narrative review was developed by a multi-disciplinary group to provide a specialty-agnostic framework for kidney-genitourinary POCUS image acquisition: indications/contraindications, patient positioning, transducer selection, acquisition sequence, and exam limitations. Finally, we describe foundational concepts in kidney-genitourinary ultrasound image interpretation, including key abnormal findings that every bedside clinician performing this modality should know.

Author Spotlight: Developing a Bedside Protocol for Kidney and Genitourinary Ultrasonography

Point-of-care ultrasound (POCUS) of the renal and genitourinary (renal-GU) system can help to screen for certain causes of kidney dysfunction. However, despite its clinical utility, renal-GU POCUS remains underutilized due to a lack of training among clinicians. To address this gap, this article describes renal-GU image acquisition and interpretation.

A range of conditions involving the kidneys and urinary bladder can cause organ-threatening complications that are preventable if diagnosed promptly with ...

Standardizing PoC TCCD Ultrasound Protocols for Critical Care in Adults

Point of Care Transcranial Color-Coded Duplex Ultrasound of the Middle Cerebral Artery

In the assessment and management of many clinical problems, point-of-care (PoC) ultrasound is an emerging bedside tool. Transcranial color-coded duplex (TCCD) ultrasound can be valuable in multiple situations, including for patients who are unconscious or have an equivocal neurologic examination, as it helps rule in specific intracranial pathologies. Despite the known diagnostic value of transcranial ultrasound, its use in critical care medicine remains variable. This variability is partly due to inconsistent training across hospitals, stemming from a lack of standardized education and training. Additionally, the brain has often been overlooked in many critical care protocols, such as RUSH (Rapid Ultrasound for Shock and Hypotension) and FAST (Focused Assessment with Sonography in Trauma) exams. To address these gaps, this article proposes a protocol for PoC TCCD image acquisition in adults, detailing indications, limitations, transducer selection, placement, sequence acquisition, and image optimization. Furthermore, the use of PoC TCCD is discussed as a means of screening for three conditions: vasospasm, raised intracranial pressure, and progression of cerebral circulatory arrest.

Transcranial ultrasound is an essential tool for monitoring patients with various neurological conditions. Although it is commonly used in a protocolized fashion in consultative studies, the brain has been overlooked in many protocols utilizing point-of-care ultrasound (PoCUS). This study proposes a PoCUS image acquisition protocol.

In the assessment and management of many clinical problems, point-of-care (PoC) ultrasound is an emerging bedside tool. Transcranial color-coded duplex ...