Thank you to Dr. Fintan Hughes for assisting with photography.

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. Informed consent was obtained from all participants. Supplemental File 1 contains the most important still images from each video.
1. Phase 1: Qualitative assessment of diaphragmatic excursion (Visual screening for gross hemidiaphragmatic dysfunction)
<ol>
	<li>Machine setup and patient positioning
	<ol>
		<li>Probe selection: Select a low-frequency (&#8804; 5 MHz) transducer (curvilinear or sector array [aka &#34;phased-array&#34;]19.</li>
		<li>Apply ultrasound coupling gel to the probe.</li>
		<li>Instrument settings: Select abdominal preset.</li>
		<li>Position the patient in the semirecumbent position.</li>
	</ol>
	</li>
	<li>Scanning technique
	<ol>
		<li>Right hemidiaphragm assessment
		<ol>
			<li>Place the probe on the right flank, 5-7th intercostal space, mid-axillary line with the beam aligned with the coronal plane of the body and probe indicator pointing cranially (Figure 1 and Figure 2A).</li>
			<li>Adjust the probe positioning (slide, fan, rock as needed) until the view is centered on the diaphragm with the following structures also visible: sub-diaphragmatic organ (liver or spleen), diaphragm, spine, and supra-diaphragmatic space (i.e., pleural space)19 (Figure 2B,C).</li>
			<li>Ask the patient to take a slow vital capacity breath in and a slow breath out.</li>
			<li>Click Acquire (or equivalent) to capture a short clip during patient respiration.</li>
			<li>Visually assess diaphragmatic excursion as one of the following: Grossly intact (Video 1 and Video 2), Grossly absent (Video 3 and Video 4), or Indeterminate (Video 5 and Video 6).</li>
			<li>If indeterminate or further quantification is needed, proceed to section 2 (Phase 2) of the protocol.</li>
		</ol>
		</li>
		<li>Left hemidiaphragm assessment: repeat steps 1.2.1.1-1.2.1.6 on the patient&#39;s left side.</li>
	</ol>
	</li>
</ol>
2. Phase 2: Quantitative assessment of ZOA excursion
<ol>
	<li>Machine setup and patient positioning
	<ol>
		<li>Probe selection: Select a high-frequency (&#62;10-13 MHz) linear transducer.</li>
		<li>Apply ultrasound coupling gel to the probe.
		<ol>
			<li>Instrument settings: Select musculoskeletal (MSK) preset if available. If MSK preset is not available, select any preset and use the same preset for all high-frequency diaphragmatic scanning.</li>
		</ol>
		</li>
		<li>Position the patient in the semirecumbent position (repeat step 1.1.4).</li>
	</ol>
	</li>
	<li>Scanning technique
	<ol>
		<li>Right hemidiaphragm assessment
		<ol>
			<li>Place the probe at the mid-axillary line at the level of the eighth or ninth intercostal spaces, with the probe indicator pointing cephalad towards the patient&#39;s head (Figure 3 and Figure 4A).</li>
			<li>Angle the beam perpendicular to the chest wall and center the axis so that the rib interspace is centered in the screen with the cranial and caudal ribs visible on the edges of the screen (Figure 4B).</li>
			<li>Set the depth such that the pleural line or diaphragm is visible in the middle third of the screen. 
			NOTE: Typically, this means a depth of 3-5 cm but can be greater if there is additional subcutaneous tissue.</li>
			<li>Set the gain such that the diaphragm/pleural line are visibly distinct from surrounding structures.</li>
			<li>Identify the pleural line on the screen.</li>
			<li>Measure the end-inspiratory location of the ZOA.
			<ol>
				<li>Give the patient the following instructions: &#34;Breathe in fully and then hold your breath in for 4 s. If you cannot tolerate 4 s, then please hold your breath for any amount of time you&#39;re comfortable.&#34;</li>
				<li>During the patient&#39;s breath hold, follow the pleural line caudally until the location is reached where the pleural line is visible in only a portion of the rib interspace, and the remaining interspace contains the diaphragm at a similar depth as the pleural line (Video 7 and Video 8). 
				NOTE: This rib interspace simultaneously containing pleura and diaphragm has been termed the Zone of Apposition (ZOA).</li>
				<li>Adjust the probe positioning (slide, fan, rock as needed) until the view is centered on the ZOA with the following structures also visible: the subcutaneous tissue above and a rib on either size of the screen (Figure 4C).</li>
				<li>Using a non-permanent skin marker, draw a line on the patient that is perpendicular to the ultrasound transducer&#39;s long axis and bisects the probe to mark the interspace where the ZOA was found (Figure 5A).&#160;The marking should be aligned with the ZOA, at the transition between the pleura and diaphragm (Figure 4B,C).</li>
				<li>Ask the patient to exhale and then &#34;breathe normally&#34; (aka tidal breathing).</li>
				<li>If unsure that one has identified the ZOA, repeat steps 2.2.1.6.1-2.2.1.6.3 and examine the presumed diaphragm in this view to see its changes during the respiratory cycle. 
				NOTE: The true diaphragm should thicken during inspiration and decrease in thickness during expiration.</li>
				<li>Repeat the measurement once (i.e., steps 2.2.1.6.1-2.2.1.6.5).</li>
				<li>Take the average of the two measurements and use this for the final value of the end-inspiratory location of the ZOA (Figure 5B).</li>
			</ol>
			</li>
			<li>Measure the end-expiatory location of the ZOA.
			<ol>
				<li>Give the patient the following instructions: &#34;Breathe in fully, then breathe out all the way, and then hold your breath out for 4 s. If you cannot tolerate 4 s, then please hold your breath for any amount of time you&#39;re comfortable.&#34;</li>
				<li>Slide the probe cranially to find the end-expiratory location of the ZOA.</li>
				<li>Repeat steps 2.2.1.6.3-2.2.1.6.4.</li>
				<li>Ask the patient to &#34;breathe normally.&#34;</li>
				<li>Repeat the measurement once (i.e., steps 2.2.1.7.1-2.2.1.7.4).</li>
				<li>Take the average of the two measurements and use this for the final value of the end-expiratory location of the ZOA.</li>
			</ol>
			</li>
			<li>Measurement of ZOA excursion
			<ol>
				<li>Measure the distance between both the averaged end-inspiratory and averaged end-expiratory skin markings in cm with a ruler. The distance between the two external skin marking represents maximal diaphragmatic excursion (Figure 5C).</li>
			</ol>
			</li>
		</ol>
		</li>
		<li>Left&#160;hemidiaphragm assessment
		<ol>
			<li>Repeat all the sub-steps contained within step 2.2.1 on the left chest.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Bronshteyn, Y. S., Blitz, J., Hashmi, N., Krishnan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Logistics+of+perioperative+diagnostic+point-of-care+ultrasound:+Nomenclature,+scope+of+practice,+training,+credentialing/privileging,+and+billing.">Logistics of perioperative diagnostic point-of-care ultrasound: Nomenclature, scope of practice, training, credentialing/privileging, and billing.</a> Int Anesthesiol Clin. 60 (3), 1-7 (2022).</li><li>Osman Elew, A. N. E., Abd Alrahman, A. A. H., El Khayat, H. M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diaphragmatic+ultrasound:+Review+article.">Diaphragmatic ultrasound: Review article.</a> The Egyptian Journal of Hospital Medicine. 87 (1), 1006-1009 (2022).</li><li>Boussuges, A., Rives, S., Finance, J., Bregeon, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+diaphragmatic+function+by+ultrasonography:+Current+approach+and+perspectives.">Assessment of diaphragmatic function by ultrasonography: Current approach and perspectives.</a> World J Clin Cases. 8 (12), 2408-2424 (2020).</li><li>Volpicelli, 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+point-of-care+lung+ultrasound.">International evidence-based recommendations for point-of-care lung ultrasound.</a> Intensive Care Med. 38 (4), 577-591 (2012).</li><li>Saad, 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=Ultrasonographic+assessment+of+diaphragmatic+function+and+its+clinical+application+in+the+management+of+patients+with+acute+respiratory+failure.">Ultrasonographic assessment of diaphragmatic function and its clinical application in the management of patients with acute respiratory failure.</a> Diagnostics (Basel). 13 (3), 411 (2023).</li><li>Santana, P. V., Cardenas, L. Z., Albuquerque, A. L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diaphragm+ultrasound+in+critically+ill+patients+on+mechanical+ventilation-evolving+concepts.">Diaphragm ultrasound in critically ill patients on mechanical ventilation-evolving concepts.</a> Diagnostics (Basel). 13 (6), 1116 (2023).</li><li>Petrof, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diaphragm+weakness+in+the+critically+ill:+Basic+mechanisms+reveal+therapeutic+opportunities.">Diaphragm weakness in the critically ill: Basic mechanisms reveal therapeutic opportunities.</a> Chest. 154 (6), 1395-1403 (2018).</li><li>Chu, S. 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=Point-of-care+application+of+diaphragmatic+ultrasonography+in+the+emergency+department+for+the+prediction+of+development+of+respiratory+failure+in+community-acquired+pneumonia:+A+pilot+study.">Point-of-care application of diaphragmatic ultrasonography in the emergency department for the prediction of development of respiratory failure in community-acquired pneumonia: A pilot study.</a> Front Med. 9, 960847 (2022).</li><li>Suttapanit, K., Wongkrasunt, S., Savatmongkorngul, S., Supatanakij, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonographic+evaluation+of+the+diaphragm+in+critically+ill+patients+to+predict+invasive+mechanical+ventilation.">Ultrasonographic evaluation of the diaphragm in critically ill patients to predict invasive mechanical ventilation.</a> J Intensive Care. 11 (1), 40 (2023).</li><li>Vivier, 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=Diaphragm+ultrasonography+to+estimate+the+work+of+breathing+during+non-invasive+ventilation.">Diaphragm ultrasonography to estimate the work of breathing during non-invasive ventilation.</a> Intensive Care Med. 38 (5), 796-803 (2012).</li><li>Eduardo Garrido-Aguirre, S. a. N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diaphragmatic+ultrasonography,+a+novel+approach+in+critical+care.">Diaphragmatic ultrasonography, a novel approach in critical care.</a> Ultrasound Q. 36, 54-58 (2020).</li><li>Sferrazza Papa, G. 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=A+review+of+the+ultrasound+assessment+of+diaphragmatic+function+in+clinical+practice.">A review of the ultrasound assessment of diaphragmatic function in clinical practice.</a> Respiration. 91 (5), 403-411 (2016).</li><li>Santana, P. V., Cardenas, L. Z., Albuquerque, A. L. P., Carvalho, C. R. R., Caruso, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diaphragmatic+ultrasound:+A+review+of+its+methodological+aspects+and+clinical+uses.">Diaphragmatic ultrasound: A review of its methodological aspects and clinical uses.</a> J Bras Pneumol. 46 (6), e20200064 (2020).</li><li>Qian, Z., Yang, M., Li, L., Chen, Y. <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+of+diaphragmatic+dysfunction+as+a+predictor+of+weaning+outcome+from+mechanical+ventilation:+A+systematic+review+and+meta-analysis.">Ultrasound assessment of diaphragmatic dysfunction as a predictor of weaning outcome from mechanical ventilation: A systematic review and meta-analysis.</a> BMJ Open. 8 (9), e021189 (2018).</li><li>Kharma, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dysfunction+of+the+diaphragm:+Imaging+as+a+diagnostic+tool.">Dysfunction of the diaphragm: Imaging as a diagnostic tool.</a> Curr Opin Pulm Med. 19 (4), 394-398 (2013).</li><li>Tsui, J. J., Tsui, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+systematic+abc+approach+to+diaphragmatic+evaluation+(abcde).">A novel systematic abc approach to diaphragmatic evaluation (abcde).</a> Can J Anaesth. 63 (5), 636-637 (2016).</li><li>Da Conceicao, 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=Validation+of+a+novel+point-of-care+ultrasound+method+to+assess+diaphragmatic+excursion.">Validation of a novel point-of-care ultrasound method to assess diaphragmatic excursion.</a> Reg Anesth Pain Med. 49 (11), 800-804 (2023).</li><li>Haaksma, M. 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=EXpert+consensus+on+diaphragm+ultrasonography+in+the+critically+ill+(EXODUS):+A+delphi+consensus+statement+on+the+measurement+of+diaphragm+ultrasound-derived+parameters+in+a+critical+care+setting.">EXpert consensus on diaphragm ultrasonography in the critically ill (EXODUS): A delphi consensus statement on the measurement of diaphragm ultrasound-derived parameters in a critical care setting.</a> Crit Care. 26 (1), 99 (2022).</li><li>El-Boghdadly, K., Goffi, A., Chan, V. <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+diaphragmatic+ultrasound+made+easy.">Point of care diaphragmatic ultrasound made easy.</a> Can J Anaesth. 64 (3), 327-328 (2017).</li><li>Kim, D. H., 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=Superior+trunk+block:+A+phrenic-sparing+alternative+to+the+interscalene+block:+A+randomized+controlled+trial.">Superior trunk block: A phrenic-sparing alternative to the interscalene block: A randomized controlled trial.</a> Anesthesiology. 131 (3), 521-533 (2019).</li><li>Bellissimo, C. A., Morris, I. S., Wong, J., Goligher, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+diaphragm+thickness+and+function+using+point-of-care+ultrasound.">Measuring diaphragm thickness and function using point-of-care ultrasound.</a> J Vis Exp. 201, e65431 (2023).</li><li>Goligher, E. 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=Measuring+diaphragm+thickness+with+ultrasound+in+mechanically+ventilated+patients:+feasibility,+reproducibility+and+validity.">Measuring diaphragm thickness with ultrasound in mechanically ventilated patients: feasibility, reproducibility and validity.</a> Intensive Care Med. 41 (4), 642-649 (2015).</li><li>Pereira, R. O. 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=Point-of-care+lung+ultrasound+in+adults:+Image+acquisition.">Point-of-care lung ultrasound in adults: Image acquisition.</a> J Vis Exp. (193), e64722 (2023).</li></ol>

We have no relevant disclosures or conflicts of interest.

POCUS offers clear advantages for diaphragmatic assessment, including portability, non-invasiveness and real-time imaging capabilities. These strengths can be taken advantage of with this feasible and accessible protocol and can be applied in a variety of clinical settings. This protocol begins with a qualitative assessment of diaphragmatic excursion to answer the question of whether gross hemi-diaphragmatic dysfunction is present. If the answer is unclear or if more specific information is needed, the second step of the...

Diagnostic ultrasound can be separated into two divisions: consultative and point-of-care. Consultative ultrasound incorporates an exam performed by a distinct specialist team, whereas POCUS is both performed and interpreted by the clinician caring for the patient in real time1.
Over the past few decades, diagnostic POCUS has emerged as a transformative tool in modern medicine, with applications rapidly expanding across specialties. These POCUS applications are driven by ultrasound&#39;s noninvasive nature, portability, and real-time imaging capabilities. Further, within diagnostic POCUS, the applications that have achieved the highest uptake in clinical medicine tend to have both reasonably high accuracy compared to a gold standard and high interobserver reliability2,3. For instance, POCUS of the lung is well established to narrow the differential diagnosis of respiratory insufficiency and has clear evidence-based guidelines supporting its standardized use4. However, while POCUS of the lung is well established, there remains an unmet need to develop a reproducible sonographic assessment of the diaphragm.
Such a non-invasive diaphragmatic assessment protocol would benefit multiple specialties and clinical situations, including but not limited to, critical care, pulmonology, perioperative care (including both general-purpose anesthesia and subspecialty regional anesthesia contexts), and neurology. In the intensive care unit, diaphragmatic dysfunction is a common concern, often arising from multiple underlying pathologies such as neuromuscular diseases, critical illness myopathy, trauma, and malnutrition5. Critically ill patients are often at high risk for both impaired contraction of the diaphragm and under-recognition of this phenomenon6. Further, diagnosing diaphragmatic dysfunction early is important, as not only can it assist in ventilation management strategies, but also dysfunction may be an early indicator of infection and sepsis7,8. In addition, prolonged intubation can lead to significant morbidity, mortality, and increased healthcare expenses2. In these scenarios, a noninvasive, portable protocol for diaphragmic assessment could be useful to assess the appropriateness for weaning from mechanical ventilation, evaluate work of breathing, and predict the probability of extubation success versus failure6,8,9,10,11.
Within regional anesthesia, diaphragmatic POCUS could have value in screening for diaphragmatic paresis related to transient phrenic nerve dysfunction from brachial plexus blocks. Although tolerated well by healthy patients, phrenic nerve palsies can lead to respiratory distress in patients with limited pulmonary reserve. Furthermore, in the perioperative arena, POCUS of the diaphragm can serve as a diagnostic tool for patients in the preoperative, intraoperative, and postoperative settings. For example, diaphragmatic POCUS could be used to detect phrenic nerve damage arising from a wide range of procedures, including but not limited to, coronary artery bypass grafting with internal mammary artery harvesting, atrial fibrillation ablation, and cervical or thoracic surgeries3,12.
Finally, within the specialty of neurology, POCUS could facilitate the assessment of diaphragmatic function in neurologic diseases such as Myasthenia gravis, Duchene&#39;s muscular dystrophy, amyotrophic lateral sclerosis, and cerebrovascular accidents13.
Accurate assessment of the diaphragm is essential due to its vital role in reparatory function. Oxygenation and ventilation depend on the generation of negative intrathoracic pressure created&#160;by the diaphragm, a dome-shaped muscle separating the abdomen and thorax that is composed of several muscular and tendinous membranes14,15. The diaphragm has at least two major components that can be distinguished on ultrasound: the dome of the diaphragm (DoD) and the zone of apposition (ZOA). The DoD is the central tendinous portion that exhibits a hyperechoic and curved appearance on ultrasound. The ZOA is the lateral portion of the diaphragm that attaches to the rib cage and consists of muscular fibers that run parallel and proximal to the inner surface of the chest wall3,15. The ZOA is thin (usually &#60;1 cm in thickness), but it increases in thickness during inspiration as the diaphragm contracts. At the ZOA, the diaphragm has a characteristic appearance on ultrasound with three layers, including an anechoic muscular layer that is bounded externally by the superficial hyperechoic parietal pleural and internally by the deep hyperechoic peritoneum3,13.
Several noninvasive sonographic protocols have been proposed for diaphragmatic assessment, involving both qualitative and quantitative approaches. Qualitative visual assessment, the simplest approach, entails the evaluation of diaphragmatic motion bilaterally, during either tidal or vital capacity breathing, using two-dimensional ultrasound, also known as Brightness mode (B-mode). In contrast, quantitative protocols typically begin with B-mode and add one-dimensional ultrasound -- also known as Motion Mode (M-mode) -- to measure one of two things: the excursion of the dome of diaphragm (DoD) and/or Diaphragmatic thickening2,3,5,13. Measurement of DoD excursion is performed with a low-frequency transducer with the ultrasound beam directed through the posterior third of the hemidiaphragm at a perpendicular angle. M-mode is then utilized to measure excursion during vital capacity breathing.
Alternatively, the measurement of diaphragmatic thickening employs a high-frequency linear transducer in two steps. First, the high-frequency transducer is placed along the patient&#39;s flank overlying the diaphragm with B-mode to identify the zone of apposition (ZOA)3.&#160;Second, estimation of diaphragmatic thickening is performed using M-mode by measuring diaphragmatic thickness (in millimeters) from the visceral to parietal pleura and calculating the change in thickness by the following equation2,3,5,13:
Change in thickness = (Thickness at end inspiration - Thickness at end expiration) / Thickness at end expiration
However, quantitative methods (DoD excursion and diaphragmatic thickening) suffer from poor interoperator reliability. Interoperator reliability is low for the measurement of DoD excursion for several reasons. First, providers have difficulty finding a consistent angle of visualization of the excursion of the dome of the diaphragm3. Second, assessing on the left side is frequently challenging due to the small acoustic window through the spleen2,16. For example, studies have cited that identification of left-sided diaphragmatic excursion is not possible in up to 65-79% of cases17. Third, intraabdominal contents and patient positioning can influence the range of diaphragm excursion2.
Similarly, the measurement of diaphragmatic thickening has low interoperator reliability for at least two reasons. First, the natural thinness of the diaphragm causes millimeter errors in measurement to be consequential. Second, the diaphragm&#39;s variability in thickness across rib interspaces and by the patient&#39;s laterality&#160;further causes measurement dispersion2,3,17. In acknowledgment of these many limitations, in 2022, an expert consensus on diaphragm ultrasonography in critically ill patients concluded that current methods were not standardized and that many required a skilled sonographer18. They noted there was no agreement on cutoff values for diaphragm dysfunction based on thickening fraction and that measurement of thickening fraction is a difficult skill with a steep learning curve13,18. Furthermore, the use of multiple different sonographic protocols in literature has added to inherent challenges by making the comparison of studies difficult, leading to heterogeneity in research19.
To address these issues, this manuscript reviews the available literature on diaphragmatic POCUS and identifies an image acquisition technique that is both simple to perform and has been shown to have high interoperator reliability. This feasible yet effective protocol begins with a qualitative evaluation of diaphragmatic excursion, followed by a recently validated quantitative assessment of excursion of the cranial-most point of the ZOA17,19.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Medical Ruler</td>
			<td>MediChoice</td>
			<td>NA</td>
			<td>We used Medichoice as that is what is readily available at our institution and it comes with the skin marker, however any medical ruler will work. The majority of skin markers come with a type of ruler or measurement system, but if not a separate ruler can be used.</td>
		</tr>
		<tr>
			<td>Skin Marker</td>
			<td>MediChoice</td>
			<td>NA</td>
			<td>We again used Medichoice as that is what is readily available at our institution and it comes with the ruler, however any standard skin marker will work.</td>
		</tr>
		<tr>
			<td>Ultrasound Gel</td>
			<td>Aquasonic</td>
			<td>NA</td>
			<td>Any standard gel will work. Sterile packs are not necessary but can be used on a case-by-case basis at the providers discretion.</td>
		</tr>
		<tr>
			<td>Ultrasound Machine&#160;</td>
			<td>Samsung and GE</td>
			<td>NA</td>
			<td>Any standard portable ultrasound machine will suffice.</td>
		</tr>
	</tbody>
</table>

diaphragmatic ultrasound in adults: image acquisition and interpretation

Diaphragm dysfunction is a widely recognized concern across numerous medical specialties and clinical settings. Timely and accurate assessment of the diaphragm is vital not only in critically ill patients, where it has a role in weaning from mechanical ventilation&#160;and respiratory outcomes, but also in the perioperative arena as a diagnostic tool to detect phrenic nerve function. Diaphragmatic assessment has traditionally utilized fluoroscopy and nerve studies that are time-consuming, costly, and non-portable. Point-of-care ultrasound (POCUS) overcomes these barriers and can be used as a tool for non-invasive screening of diaphragm function. However, POCUS for diaphragmatic dysfunction currently suffers from several issues such as a lack of consensus guidelines, a multiplicity of protocols, and poor interoperator reliability among existing protocols, most notably with the assessment of dome of diaphragm excursion and diaphragmatic thickening. To address these issues, this manuscript reviews the available literature on diaphragmatic POCUS and identifies an image acquisition technique that is both simple to perform and has high interoperator reliability. This technique first describes a qualitative evaluation of diaphragm excursion, followed by a quantitative assessment of the excursion of the zone of apposition. The technique is described stepwise along with all the following: patient positioning, transducer selection, probe placement, image optimization, and interpretation.

This diaphragmatic ultrasound protocol begins with the qualitative assessment of each hemithorax during a vital capacity breath to sort each hemidiaphragm into one of three categories: grossly intact excursion, grossly impaired excursion, or indeterminate. Examples of grossly normal vital capacity excursion of the right and left hemidiaphragms are shown in Video 1 and Video 2, respectively. Examples of grossly impaired vital capacity excursion of the right and left hemidiaphragms are sho...

Point-of-care ultrasound (POCUS) is an essential technique for screening for diaphragmatic dysfunction due to its portability, non-invasiveness, and real-time imaging capabilities. Although current diaphragmatic POCUS protocols exist, they suffer from poor interoperator reliability and lack consensus guidelines. Here we describe a technique that is reproducible and simple to perform.

Diaphragmatic Ultrasound in Adults: Image Acquisition and Interpretation

Diaphragm dysfunction is a widely recognized concern across numerous medical specialties and clinical settings. Timely and accurate assessment of the ...

diaphragmatic-ultrasound-adults-image-acquisition

Research

JoVE Journal

Medicine

285 Views.  University of Pittsburgh Medical Center. Point-of-care ultrasound (POCUS) is an essential technique for screening for diaphragmatic dysfunction due to its portability, non-invasiveness, and real-time imaging capabilities. Although current diaphragmatic POCUS protocols exist, they suffer from poor interoperator reliability and lack consensus guidelines. Here we describe a technique that is reproducible and simple to perform.

Video: Diaphragmatic Ultrasound in Adults: Image Acquisition and Interpretation

Collecting Saliva and Measuring Salivary Cortisol and Alpha-amylase in Frail Community Residing Older Adults via Family Caregivers

Salivary measures have emerged in bio-behavioral research that are easy-to-collect, minimally invasive, and relatively inexpensive biologic markers of stress. This article we present the steps for collection and analysis of two salivary assays in research with frail, community residing older adults-salivary cortisol and salivary alpha amylase. The field of salivary bioscience is rapidly advancing and the purpose of this presentation is to provide an update on the developments for investigators interested in integrating these measures into research on aging. Strategies are presented for instructing family caregivers in collecting saliva in the home, and for conducting laboratory analyses of salivary analytes that have demonstrated feasibility, high compliance, and yield quality specimens. The protocol for sample collection includes: (1) consistent use of collection materials; (2) standardized methods that promote adherence and minimize subject burden; and (3) procedures for controlling certain confounding agents. We also provide strategies for laboratory analyses include: (1) saliva handling and processing; (2) salivary cortisol and salivary alpha amylase assay procedures; and (3) analytic considerations.

We demonstrate: (1) procedures for collection of salivary samples in cognitive impaired older adults by family caregivers in the home setting, (2) procedures for measuring stress activity via salivary cortisol and alpha amylase, and (3) representative profiles. Protocols that allow researchers to study stress-linked processes advance our understanding of biological sensitivity and susceptibility.

Salivary measures have emerged in bio-behavioral research  that are easy-to-collect, minimally invasive, and relatively inexpensive  biologic markers of ...

Clinical Assessment of Spatiotemporal Gait Parameters in Patients and Older Adults

Spatial and temporal characteristics of human walking are frequently evaluated to identify possible gait impairments, mainly in orthopedic and neurological patients1-4, but also in healthy older adults5,6. The quantitative gait analysis described in this protocol is performed with a recently-introduced photoelectric system (see&#160;Materials table) which has the potential to be used in the clinic because it is portable, easy to set up (no subject preparation is required before a test), and does not require maintenance and sensor calibration. The photoelectric system consists of series of high-density floor-based photoelectric cells with light-emitting and light-receiving diodes that are placed parallel to each other to create a corridor, and are oriented perpendicular to the line of progression7. The system simply detects interruptions in light signal, for instance due to the presence of feet within the recording area. Temporal gait parameters and 1D spatial coordinates of consecutive steps are subsequently calculated to provide common gait parameters such as step length, single limb support and walking velocity8, whose validity against a criterion instrument has recently been demonstrated7,9. The measurement procedures are very straightforward; a single patient can be tested in less than 5 min&#160;and a comprehensive report can be generated in less than 1&#160;min.

This protocol is used to evaluate spatial and temporal gait variables of neurological/orthopedic patients and older persons by means of a recently-introduced floor-based photocell system.

Spatial and temporal characteristics of human walking are frequently evaluated to identify possible gait impairments, mainly in orthopedic and ...

Knee Arthrocentesis in Adults

Arthrocentesis of the knee is a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. An arthrocentesis can be diagnostic or therapeutic. Synovial fluid may be removed for testing to determine the nature of the knee effusion. If septic arthritis is suspected, urgent arthrocentesis before initiation of antibiotic treatment is indicated. Moreover, arthrocentesis can also aid in diagnosing crystal-induced arthritis such as gout or pseudogout, or non-inflammatory arthritis such as osteoarthritis. Identifying the cause of the knee effusion can guide treatment. Furthermore, removing fluid from a knee can reduce intraarticular pressure to decrease pain and improve range of motion. There is no absolute contraindication to performing this procedure, but in selecting the needle entry site, an area of skin that is infected should be avoided. Therefore, caution should be exercised when a patient presents with suspected cellulitis over the knee joint to avoid the potential risk of causing iatrogenic septic arthritis. A knee that has undergone arthroplasty should be assessed for arthrocentesis by an orthopedic surgeon. Arthrocentesis of the knee is typically performed with the patient supine. The site for needle insertion is marked, and then the skin is disinfected. After a local anesthetic is administered, a needle is inserted along the pathway that was anesthetized. Synovial fluid is aspirated, and then the needle is withdrawn. Pressure is applied until any bleeding stops. The synovial fluid can be analyzed for infection and inflammation but cannot directly confirm a diagnosis of internal derangement or autoimmune causes of arthritis. In addition to the history and physical examination, laboratory findings and imaging can clarify the etiology of a knee effusion.

Here the protocol describes arthrocentesis of the knee, a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. Synovial fluid may be removed for testing to determine the nature of the knee effusion. Arthrocentesis of the knee is typically performed with the patient supine.

Arthrocentesis of the knee is a procedure in which a needle is inserted into the knee joint, and synovial fluid is aspirated. An arthrocentesis can be ...

Drug Treatment by Central Venous Catheter in a Mouse Model of Angiotensin II Induced Abdominal Aortic Aneurysm and Monitoring by 3D Ultrasound

Since pharmaceutical treatment options are lacking in the clinical management of abdominal aortic aneurysm (AAA), animal models, in particular mouse models, are applied to advance the understanding of the disease pathogenesis and to identify potential therapeutic targets. Testing novel drug candidates to block AAA growth in these models generally requires repeated drug administration during the time course of the experiment. Here, we describe a compiled protocol for AAA induction, insertion of an intravenous catheter to facilitate prolonged therapy, and serial AAA monitoring by 3D ultrasound. Aneurysms are induced in apolipoprotein E (ApoE) deficient mice by angiotensin II release over 28 days from osmotic mini-pumps implanted subcutaneously into the mouse back. Subsequently, the surgical procedure for external jugular vein catheterization is conducted to allow for daily intravenous drug treatment or repeated blood sampling via a subcutaneous vascular access button. Despite the two dorsal implants, the monitoring of AAA development is readily facilitated by sequential semi-automated 3D ultrasound analysis, which yields comprehensive information on the expansion of aortic diameter and volume and on aneurysm morphology, as illustrated by experimental examples.

This protocol describes the consecutive implantation of an osmotic pump to induce abdominal aortic aneurysm by angiotensin II release in apolipoprotein E (ApoE) deficient mice and of a vascular access port with a jugular vein catheter for repeated drug treatment. Monitoring of aneurysm development by 3D ultrasound is effectively conducted despite dorsal implants.

Since pharmaceutical treatment options are lacking in the clinical management of abdominal aortic aneurysm (AAA), animal models, in particular mouse ...

Image Acquisition using Portable Sonography for Emergency Airway Management

With its increasing popularity and accessibility, portable ultrasonography has been rapidly adapted not only to improve the perioperative care of patients, but also to address the potential benefits of employing ultrasound in airway management. The benefits of point of care ultrasound (POCUS) include its portability, the speed at which it can be utilized, and its lack of invasiveness or exposure of the patient to radiation of other imaging modalities.
Two primary indications for airway POCUS include confirmation of endotracheal intubation and identification of the cricothyroid membrane in the event a surgical airway is required. In this article, the technique of using ultrasound to confirm endotracheal intubation and the relevant anatomy is described, along with the associated ultrasonographic images. In addition, identification of the anatomy of the cricothyroid membrane and the ultrasonographic acquisition of appropriate images to perform this procedure are reviewed.
Future advances include utilizing airway POCUS to identify patient characteristics that might indicate difficult airway management. Traditional bedside clinical exams have, at best, fair predictive values. The addition of ultrasonographic airway assessment has the potential to improve this predictive accuracy. This article describes the use of POCUS for airway management, and initial evidence suggests that this has improved the diagnostic accuracy of predicting a difficult airway. Given that one of the limitations of airway POCUS is that it requires a skilled sonographer, and image analysis can be operator dependent, this paper will provide recommendations to standardize the technical aspects of airway ultrasonography and promote further research utilizing sonography in airway management. The goal of this protocol is to educate researchers and medical health professionals and to advance the research in the field of airway POCUS.

Point of care ultrasound (POCUS) is increasingly being utilized in airway management. Presented here are some clinical utilities of POCUS, including differentiating endotracheal and esophageal intubation, identification of the cricothyroid membrane in the event a surgical airway is required, and measuring anterior neck soft tissue to predict difficult airway management.

With its increasing popularity and accessibility, portable ultrasonography has been rapidly adapted not only to improve the perioperative care of ...

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 ...

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 ...

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 ...

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 ...