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><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&amp;nbsp;</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

355 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 ...

Diagnostic Ultrasound Imaging of Mouse Diaphragm Function

Function analysis of rodent respiratory skeletal muscles, particularly the diaphragm, is commonly performed by isolating muscle strips using invasive surgical procedures. Although this is an effective method of assessing in vitro diaphragm activity, it involves non-survival surgery. The application of non-invasive ultrasound imaging as an in vivo procedure is beneficial since it not only reduces the number of animals sacrificed, but is also suitable for monitoring disease progression in live mice. Thus, our ultrasound imaging method may likely assist in the development of novel therapies that alleviate muscle injury induced by various respiratory diseases. Particularly, in clinical diagnoses of obstructive lung diseases, ultrasound imaging has the potential to be used in conjunction with other standard tests to detect the early onset of diaphragm muscle fatigue. In the current protocol, we describe how to accurately evaluate diaphragm contractility in a mouse model using a diagnostic ultrasound imaging technique.

Diagnostic ultrasound imaging has proven to be effective in diagnosing various respiratory diseases in human and animal subjects. We demonstrate a comprehensive ultrasound protocol utilized by Dr. Zuo's lab to analyze diaphragm kinetics specifically in mouse models. This is also a non-invasive research technique which can provide quantitative information on mouse respiratory muscle function.

Function analysis of rodent respiratory skeletal muscles, particularly the diaphragm, is commonly performed by isolating muscle strips using invasive ...

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 ...

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 ...

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 ...

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 ...

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 ...