None. No funding was received for this project.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
NOTE: The exams can be performed with either a low frequency curvilinear (2-5 MHz) or medium to high frequency linear probe (6-12 MHz) depending on patient body habitus, probe availability, and provider preference. For the figures and scans, a curvilinear probe (C35xp, SonoSite M-Turbo) was utilized.
1. Technique for quadriceps scanning
<ol>
	<li>Quadriceps depth measurement
	<ol>
		<li>Patient positioning: Place the patient in a supine position (head of the bed elevated to 30o) with their legs extended.</li>
		<li>Probe selection: Select a low-frequency curvilinear or medium to high-frequency linear probe.</li>
		<li>Mode selection: Set the preset (i.e., exam type) on the scanner to musculoskeletal (MSK) setting.</li>
		<li>Probe placement:
		<ol>
			<li>Place the probe transversely on the anterior thigh at approximately 60% the length from the anterior superior iliac spine (ASIS) to the superior border of the patella (Figure 1).</li>
			<li>With the probe perpendicular to the long axis of the muscles, the quadriceps will appear deep to the subcutaneous tissue and superficial to the femur.</li>
			<li>Use extra contact gel to minimize underlying soft tissue distortion.</li>
		</ol>
		</li>
		<li>Image optimization:
		<ol>
			<li>To prevent the overestimation of the muscle thickness due to superficial edema, apply firm pressure to the ultrasound probe without inflicting pain25.</li>
			<li>If any difficulty identifying the rectus femoris is encountered, ask the patient to contract their thigh muscles or extend their knee. The rectus femoris, being superficial and crossing the hip joint, will show a different movement pattern compared to the deeper vastus muscles (Supplementary Video 1).</li>
		</ol>
		</li>
		<li>Measurement of quadriceps muscle thickness
		<ol>
			<li>Activate the Caliper function of the ultrasound machine by pressing Measure on the ultrasound machine.</li>
			<li>Use the cursor to measure the anterior-to-posterior distance between (1) the deep border of the vastus intermedius (just superficial to the cortex of the femur) and (2) the most superficial fascia of the rectus femoris (Figure 2). 
			NOTE: If there is any difficulty identifying the structures mentioned in 1.1.6.2, the steps mentioned in the Video 1 supplement can be repeated before activating the caliper function. The quadriceps muscle thickness is the sum of the muscle thickness of the rectus femoris and vastus intermedius (Figure 3).</li>
		</ol>
		</li>
		<li>Image acquisition: click on Acquire to save a video clip of this sonographic view.</li>
		<li>Repeat measurement (steps 1.1.6-1.1.7) three times and average values to minimize variability.</li>
	</ol>
	</li>
</ol>
2. Technique for rectus femoris scanning
<ol>
	<li>Rectus femoris cross-sectional area (CSA) measurement
	<ol>
		<li>Patient positioning: follow step 1.1.1.</li>
		<li>Probe selection: follow step 1.1.2.</li>
		<li>Mode selection: follow step 1.1.3.</li>
		<li>Probe placement: follow step 1.1.4.</li>
		<li>Image optimization:
		<ol>
			<li>Adjust the depth using the vertical ruler on the right side of the displayed scan. Adjust the gain using the horizontal slide bar at the bottom of the touch control panel so that the rectus femoris muscle is centered in the ultrasound frame with clear visualization of its boundaries and the underlying femur.</li>
			<li>Identify the rectus femoris muscle as a hypoechoic structure within the anterior thigh compartment, with a central echogenic line representing the intramuscular tendon.</li>
			<li>Activate the caliper function on the ultrasound machine and trace around the periphery of the rectus femoris muscle carefully to define its cross-sectional area. The ultrasound machine will calculate and display the CSA based on the tracing.</li>
		</ol>
		</li>
		<li>Image acquisition: follow step 1.1.6.</li>
		<li>Repeat measurement three times and average values to minimize variability.</li>
	</ol>
	</li>
	<li>Rectus Femoris Circumference Measurement
	<ol>
		<li>Patient positioning: follow step 1.1.1.</li>
		<li>Probe selection: follow step 1.1.2.</li>
		<li>Mode selection: follow step 1.1.3.</li>
		<li>Probe placement: follow step 1.1.4</li>
		<li>Image optimization:
		<ol>
			<li>Adjust the depth using the vertical ruler on the right side of the displayed scan. Adjust the gain using the horizontal slide bar at the bottom of the touch control panel so that the rectus femoris muscle is centered in the ultrasound frame with clear visualization of its boundaries and the underlying femur.</li>
			<li>Identify the rectus femoris muscle as a hypoechoic structure within the anterior thigh compartment, with a central echogenic line representing the intramuscular tendon.</li>
			<li>Activate the caliper function on the ultrasound machine and trace around the periphery of the rectus femoris muscle carefully to define its cross-sectional area. The ultrasound machine will calculate and display the circumference based on the tracing (Figure 4).</li>
		</ol>
		</li>
		<li>Image acquisition: follow step 1.1.6.</li>
		<li>Repeat measurement three times and average values to minimize variability.</li>
	</ol>
	</li>
</ol>

Ultrasound Protocol for Perioperative Frailty Assessment

<ol><li>Etzioni, D. A., Liu, J. H., O'Connell, J. B., Maggard, M. A., Ko, C. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Elderly+patients+in+surgical+workloads%3A+A+population-based+analysis%5BTitle%5D)+AND+%22Am+Surg%22%5BJournal%5D)">Elderly patients in surgical workloads: A population-based analysis.</a> Am Surg. 69 (11), 961-965 (2003).</li>
<li>Rohrmann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epidemiology+of+frailty+in+older+people%5BTitle%5D)+AND+%22Adv+Exp+Med+Biol%22%5BJournal%5D)">Epidemiology of frailty in older people.</a> Adv Exp Med Biol. 1216, 21-27 (2020).</li>
<li>Clegg, A., Young, J., Iliffe, S., Rikkert, M. O., Rockwood, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+in+elderly+people%5BTitle%5D)+AND+%22Lancet%22%5BJournal%5D)">Frailty in elderly people.</a> Lancet. 381 (9868), 752-762 (2013).</li>
<li>Torpy, J. M., Lynm, C., Glass, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+in+older+adults%5BTitle%5D)+AND+%22JAMA%22%5BJournal%5D)">Frailty in older adults.</a> JAMA. 296 (18), 2280(2006).</li>
<li>Arya, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+increases+the+risk+of+30-day+mortality%2C+morbidity%2C+and+failure+to+rescue+after+elective+abdominal+aortic+aneurysm+repair+independent+of+age+and+comorbidities%5BTitle%5D)+AND+%22J+Vasc+Surg%22%5BJournal%5D)">Frailty increases the risk of 30-day mortality, morbidity, and failure to rescue after elective abdominal aortic aneurysm repair independent of age and comorbidities.</a> J Vasc Surg. 61 (2), 324-331 (2015).</li>
<li>Engelhardt, K. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+screening+and+a+frailty+pathway+decrease+length+of+stay%2C+loss+of+independence%2C+and+30-day+readmission+rates+in+frail+geriatric+trauma+and+emergency+general+surgery+patients%5BTitle%5D)+AND+%22J+Trauma+Acute+Care+Surg%22%5BJournal%5D)">Frailty screening and a frailty pathway decrease length of stay, loss of independence, and 30-day readmission rates in frail geriatric trauma and emergency general surgery patients.</a> J Trauma Acute Care Surg. 85 (1), 167-173 (2018).</li>
<li>Gans, E. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+and+treatment+decisions+in+older+patients+with+vulvar+cancer%3A+A+single-center+cohort+study%5BTitle%5D)+AND+%22J+Geriatr+Oncol%22%5BJournal%5D)">Frailty and treatment decisions in older patients with vulvar cancer: A single-center cohort study.</a> J Geriatr Oncol. 14 (2), 101442(2023).</li>
<li>Carlstrom, L. P., Helal, A., Perry, A., Lakomkin, N., Graffeo, C. S., Clarke, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Too+frail+is+to+fail%3A+Frailty+portends+poor+outcomes+in+the+elderly+with+type+II+odontoid+fractures+independent+of+management+strategy%5BTitle%5D)+AND+%22J+Clin+Neurosci%22%5BJournal%5D)">Too frail is to fail: Frailty portends poor outcomes in the elderly with type II odontoid fractures independent of management strategy.</a> J Clin Neurosci. 93, 48-53 (2021).</li>
<li>Ho, V. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Health+status%2C+frailty%2C+and+multimorbidity+in+patients+with+emergency+general+surgery+conditions%5BTitle%5D)+AND+%22Surgery%22%5BJournal%5D)">Health status, frailty, and multimorbidity in patients with emergency general surgery conditions.</a> Surgery. 172 (1), 446-452 (2022).</li>
<li>Modrall, J. G., Tsai, S., Ramanan, B., Rosero, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+as+a+predictor+of+mortality+for+fenestrated+EVAR+and+open+surgical+repair+of+aortic+aneurysms+involving+visceral+vessels%5BTitle%5D)+AND+%22Ann+Vasc+Surg%22%5BJournal%5D)">Frailty as a predictor of mortality for fenestrated EVAR and open surgical repair of aortic aneurysms involving visceral vessels.</a> Ann Vasc Surg. 80, 29-36 (2022).</li>
<li>Lee, A. C. H., Lee, S. M., Ferguson, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+is+associated+with+adverse+postoperative+outcomes+after+lung+cancer+resection%5BTitle%5D)+AND+%22JTO+Clin+Res+Rep%22%5BJournal%5D)">Frailty is associated with adverse postoperative outcomes after lung cancer resection.</a> JTO Clin Res Rep. 3 (11), 100414(2022).</li>
<li>Mah, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+five-factor+modified+frailty+index+predicts+adverse+postoperative+and+chemotherapy+outcomes+in+gynecologic+oncology%5BTitle%5D)+AND+%22Gynecol+Oncol%22%5BJournal%5D)">The five-factor modified frailty index predicts adverse postoperative and chemotherapy outcomes in gynecologic oncology.</a> Gynecol Oncol. 166 (1), 154-161 (2022).</li>
<li>Ogawa, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Impact+of+frailty+on+postoperative+dysphagia+in+patients+undergoing+elective+cardiovascular+surgery%5BTitle%5D)+AND+%22JACC+Asia%22%5BJournal%5D)">Impact of frailty on postoperative dysphagia in patients undergoing elective cardiovascular surgery.</a> JACC Asia. 2 (1), 104-113 (2022).</li>
<li>Huq, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+in+patients+undergoing+surgery+for+brain+tumors%3A+A+systematic+review+of+the+literature%5BTitle%5D)+AND+%22World+Neurosurg%22%5BJournal%5D)">Frailty in patients undergoing surgery for brain tumors: A systematic review of the literature.</a> World Neurosurg. 166, 268-278 (2022).</li>
<li>Owodunni, O. P., Mostales, J. C., Qin, C. X., Gabre-Kidan, A., Magnuson, T., Gearhart, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preoperative+frailty+assessment%2C+operative+severity+score%2C+and+early+postoperative+loss+of+independence+in+surgical+patients+age+65+years+or+older%5BTitle%5D)+AND+%22J+Am+Coll+Surg%22%5BJournal%5D)">Preoperative frailty assessment, operative severity score, and early postoperative loss of independence in surgical patients age 65 years or older.</a> J Am Coll Surg. 232 (4), 387-395 (2021).</li>
<li>DeAngelo, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Impact+of+frailty+on+risk+of+long-term+functional+decline+following+vascular+surgery%5BTitle%5D)+AND+%22J+Vasc+Surg%22%5BJournal%5D)">Impact of frailty on risk of long-term functional decline following vascular surgery.</a> J Vasc Surg. 77 (2), 515-522 (2023).</li>
<li>Rothenberg, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Association+of+frailty+and+postoperative+complications+with+unplanned+readmissions+after+elective+outpatient+surgery%5BTitle%5D)+AND+%22JAMA+Netw+Open%22%5BJournal%5D)">Association of frailty and postoperative complications with unplanned readmissions after elective outpatient surgery.</a> JAMA Netw Open. 2 (5), e194330(2019).</li>
<li>Sastry, R. A., Pertsch, N. J., Tang, O., Shao, B., Toms, S. A., Weil, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+and+outcomes+after+craniotomy+for+brain+tumor%5BTitle%5D)+AND+%22J+Clin+Neurosci%22%5BJournal%5D)">Frailty and outcomes after craniotomy for brain tumor.</a> J Clin Neurosci. 81, 95-100 (2020).</li>
<li>Shinall, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Association+of+preoperative+patient+frailty+and+operative+stress+with+postoperative+mortality%5BTitle%5D)+AND+%22JAMA+Surg%22%5BJournal%5D)">Association of preoperative patient frailty and operative stress with postoperative mortality.</a> JAMA Surg. 155 (1), e194620(2020).</li>
<li>Kennedy, C. A., Shipway, D., Barry, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+and+emergency+abdominal+surgery%3A+A+systematic+review+and+meta-analysis%5BTitle%5D)+AND+%22Surgeon%22%5BJournal%5D)">Frailty and emergency abdominal surgery: A systematic review and meta-analysis.</a> Surgeon. 20 (6), e307-e314 (2022).</li>
<li>Fried, L. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frailty+in+older+adults%3A+Evidence+for+a+phenotype%5BTitle%5D)+AND+%22J+Gerontol+A+Biol+Sci+Med+Sci%22%5BJournal%5D)">Frailty in older adults: Evidence for a phenotype.</a> J Gerontol A Biol Sci Med Sci. 56 (3), M146-M157 (2001).</li>
<li>Knoedler, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Impact+of+sarcopenia+on+outcomes+in+surgical+patients%3A+A+systematic+review+and+meta-analysis%5BTitle%5D)+AND+%22Int+J+Surg%22%5BJournal%5D)">Impact of sarcopenia on outcomes in surgical patients: A systematic review and meta-analysis.</a> Int J Surg. 109 (12), 4238-4262 (2023).</li>
<li>Canales, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preoperative+point-of-care+ultrasound+to+identify+frailty+and+predict+postoperative+outcomes%3A+A+diagnostic+accuracy+study%5BTitle%5D)+AND+%22Anesthesiology%22%5BJournal%5D)">Preoperative point-of-care ultrasound to identify frailty and predict postoperative outcomes: A diagnostic accuracy study.</a> Anesthesiology. 136 (2), 268-278 (2022).</li>
<li>Pasta, G., Nanni, G., Molini, L., Bianchi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sonography+of+the+quadriceps+muscle%3A+Examination+technique%2C+normal+anatomy%2C+and+traumatic+lesions%5BTitle%5D)+AND+%22J+Ultrasound%22%5BJournal%5D)">Sonography of the quadriceps muscle: Examination technique, normal anatomy, and traumatic lesions.</a> J Ultrasound. 13 (2), 76-84 (2010).</li>
<li>Pardo, E., El Behi, H., Boizeau, P., Verdonk, F., Alberti, C., Lescot, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Reliability+of+ultrasound+measurements+of+quadriceps+muscle+thickness+in+critically+ill+patients%5BTitle%5D)+AND+%22BMC+Anesthesiol%22%5BJournal%5D)">Reliability of ultrasound measurements of quadriceps muscle thickness in critically ill patients.</a> BMC Anesthesiol. 18 (1), 205(2018).</li>
<li>Nijholt, W., Scafoglieri, A., Jager-Wittenaar, H., Hobbelen, J. S. M., Van Der Schans, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+reliability+and+validity+of+ultrasound+to+quantify+muscles+in+older+adults%3A+a+systematic+review%5BTitle%5D)+AND+%22J+Cachexia+Sarcopenia+Muscle%22%5BJournal%5D)">The reliability and validity of ultrasound to quantify muscles in older adults: a systematic review.</a> J Cachexia Sarcopenia Muscle. 8 (5), 702-712 (2017).</li>
<li>Hogenbirk, R. N. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thickness+of+biceps+and+quadriceps+femoris+muscle+measured+using+point-of-care+ultrasound+as+a+representation+of+total+skeletal+muscle+mass%5BTitle%5D)+AND+%22J+Clin+Med%22%5BJournal%5D)">Thickness of biceps and quadriceps femoris muscle measured using point-of-care ultrasound as a representation of total skeletal muscle mass.</a> J Clin Med. 11 (22), 6606(2022).</li>
<li>Lambell, K. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparison+of+ultrasound-derived+muscle+thickness+with+computed+tomography+muscle+cross-sectional+area+on+admission+to+the+intensive+care+unit%3A+A+pilot+cross-sectional+study%5BTitle%5D)+AND+%22JPEN+J+Parenter+Enteral+Nutr%22%5BJournal%5D)">Comparison of ultrasound-derived muscle thickness with computed tomography muscle cross-sectional area on admission to the intensive care unit: A pilot cross-sectional study.</a> JPEN J Parenter Enteral Nutr. 45 (1), 136-145 (2021).</li>
<li>Zhao, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Evaluation+of+appendicular+muscle+mass+in+sarcopenia+in+older+adults+using+ultrasonography%3A+A+systematic+review+and+meta-analysis%5BTitle%5D)+AND+%22Gerontology%22%5BJournal%5D)">Evaluation of appendicular muscle mass in sarcopenia in older adults using ultrasonography: A systematic review and meta-analysis.</a> Gerontology. 68 (10), 1174-1198 (2022).</li>
<li>Ghaffarian, A. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Prognostic+implications+of+diagnosing+frailty+and+sarcopenia+in+vascular+surgery+practice%5BTitle%5D)+AND+%22J+Vasc+Surg%22%5BJournal%5D)">Prognostic implications of diagnosing frailty and sarcopenia in vascular surgery practice.</a> J Vasc Surg. 70 (3), 892-900 (2019).</li>
<li>Martin, F. C., Ranhoff, A. H. Frailty and Sarcopenia. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aMartin%2C+FC+%22Orthogeriatrics%3A+The+Management+of+Older+Patients+with+Fragility+Fractures%22">Orthogeriatrics: The Management of Older Patients with Fragility Fractures</a>. , Springer. Cham. (2021).</li>
<li>Davies, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Differential+association+of+frailty+and+sarcopenia+with+mortality+and+disability%3A+Insight+supporting+clinical+subtypes+of+frailty%5BTitle%5D)+AND+%22J+Am+Med+Dir+Assoc%22%5BJournal%5D)">Differential association of frailty and sarcopenia with mortality and disability: Insight supporting clinical subtypes of frailty.</a> J Am Med Dir Assoc. 23 (10), 1712-1716 (2022).</li>
<li>Ben-Menachem, E., Ashes, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Point-of-care+ultrasound+frailty+assessments%5BTitle%5D)+AND+%22Comment.+Anesthesiology%22%5BJournal%5D)">Point-of-care ultrasound frailty assessments.</a> Comment. Anesthesiology. 137 (3), 373-374 (2022).</li>
<li>Ijaz, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Interventions+for+frailty+among+older+adults+with+cardiovascular+disease%5BTitle%5D)+AND+%22J+Am+Collo+Cardiol%22%5BJournal%5D)">Interventions for frailty among older adults with cardiovascular disease.</a> J Am Collo Cardiol. 79 (5), 482-503 (2022).</li>
<li>Thompson, C., Dodds, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+ageing+syndromes+of+sarcopenia+and+frailty%5BTitle%5D)+AND+%22Medicine%22%5BJournal%5D)">The ageing syndromes of sarcopenia and frailty.</a> Medicine. 49 (1), 6-9 (2021).</li>
</ol>

None of the authors have any conflicts of interest to disclose.

Previous studies have indicated that POCUS can be used to estimate muscle thickness, including the quadriceps muscle, with accuracy comparable to CT scans26,27,28. Sonographic measurement of quadriceps muscle thickness has been correlated with frailty and can be used to predict certain postoperative outcomes23. In addition, this method is helpful in situations where other methods of diagnosing frailty may be impractical, such as in the preoperative setting or in cases where the patient or provider is unable to participate in a lengthy examination.
A recent systematic review and meta-analysis conducted on the evaluation of appendicular muscle mass in sarcopenia in older adults using ultrasonography assessed ultrasonography&#39;s reliability and validity in assessing muscle mass in the elderly, particularly through the measurement of the thickness and cross-sectional area of rectus femoris or gastrocnemius muscles. The review found that these sonographic parameters accurately diagnosed sarcopenia, offering a non-invasive and effective tool for clinical assessment in geriatric populations29.
There are limitations to using POCUS to estimate preoperative frailty and predict postoperative outcomes. While sarcopenia and frailty are closely linked, sarcopenia alone may not be as predictive of postoperative mortality compared to a diagnosis of frailty30,31,32. This test utilizes muscle thickness to predict frailty-related outcomes, identifying only one part of the multisystem syndrome of frailty and cannot identify cognitive decline or other physical changes associated with the disorder. While the method described in this manuscript showed clinical utility in at least one clinical study23, muscle loss is known to vary by body shape, gender, and ethnicity33. Moreover, chronic conditions prevalent in different demographic groups can further complicate the applicability of the bedside assessment technique. Factors such as underlying health conditions, medication use, and varying levels of physical activity can influence muscle composition and thus impact the accuracy of the assessment. Therefore, larger-scale studies across different patient populations are needed to confirm the utility of this bedside assessment technique.
Operator error can also contribute to the limitations of this technique. Since there is a learning curve associated with this POCUS technique, strategies to mitigate operator variability to ensure accuracy and reliability must be established, such as standardizing training protocols, ongoing quality assurance measures, and proficiency assessments. These steps can enhance the reproducibility and validity of POCUS-based frailty assessments in diverse clinical settings.
To enhance the validation of POCUS in predicting long-term outcomes and its integration into clinical medicine, future research avenues should prioritize longitudinal studies assessing the correlation between sonographic measurements of muscle thickness and patient outcomes over extended periods. Such investigations would not only validate the efficacy of POCUS in identifying frailty but also elucidate its predictive power for postoperative morbidity and mortality in diverse patient populations. Additionally, studies focusing on the integration of POCUS into existing clinical protocols are crucial to establishing standardized guidelines for its implementation across different healthcare settings. Moreover, efforts should be directed toward refining operator training protocols and quality assurance measures to minimize variability and ensure the reliability of POCUS-based frailty assessments.
As the population of patients undergoing surgery continues to age, the identification of frailty becomes increasingly important to anticipate postoperative needs and guide operative planning. This paper supports further validation of the utility of POCUS to measure quadriceps depth as an alternative to time-consuming or costly evaluations for frailty. Ultimately, while there are no drug treatments for frailty, non-pharmacological interventions, such as addressing poor nutrition and cognitive disorders, may be able to improve future surgical outcomes in affected patients34,35.

As the average life expectancy rises globally, an increasing number of surgeries are performed on patients over the age of 651. Frailty is more common in these patients compared with their younger counterparts and represents a state of physiological vulnerability to stressors, including surgery2,3,4. Frailty in the preoperative setting has been linked with a higher risk for postoperative adverse events across many surgical subspecialties5,6,7,8,9,10,11,12,13, including longer hospital length of stay10,14, loss of independence15,16, readmission rates17,18, increased costs14, and mortality10,18,19,20. Therefore, it is of utmost importance for the perioperative healthcare team to consider a patient&#39;s frailty during preoperative decision-making.
The most commonly used method to diagnose frailty includes the Fried frailty phenotype, which comprises five factors including exhaustion, weakness (measured by grip strength), slow walking pace, weight loss, and low physical activity levels21. However, this scale was designed primarily for outpatient services and may be too time-consuming in the perioperative setting. In addition, it requires patient cooperation and is impractical in a patient with altered mental status. Moreover, CT scans are used to assess muscle mass for sarcopenia diagnosis, which can aid in frailty assessment. However, while effective, CT scans present practical challenges in resource allocation and expose patients to ionizing radiation, especially in the perioperative period.22&#160;Therefore, there is a need for bedside test that can quickly and accurately identify preoperative patients with diminished muscle mass, thus flagging those at higher surgical risk.
Recently, Canales et al. reported on a method for screening for frailty in the preoperative setting using point-of-care ultrasound23. They found that quadriceps muscle thickness accurately predicted frailty and was an independent predictor of postoperative discharge to a skilled nursing facility and delirium. The quadriceps muscle is located on the anterior thigh and is composed of four muscle bellies: the rectus femoris, the vastus medialis, vastus lateralis, and the vastus intermedius24. Using point-of-care ultrasound for frailty screening in the preoperative setting offers advantages over the Fried frailty assessment and CT imaging. Point-of-care ultrasound provides objective measures of physiologic parameters, such as muscle mass and quality, in real-time, allowing for immediate and non-invasive evaluation. This approach is more practical, efficient, and adaptable to patients who may not be able to undergo traditional assessment, enhancing perioperative risk stratification and improving outcomes23.
This paper will detail how to obtain the point-of-care ultrasound measurements of the quadriceps (including probe selection, patient positioning, and troubleshooting) and discuss the implications of this measurement in the perioperative setting.

<table><tbody><tr><td>High Frequency Ultrasound Probe (HFL38xp)</td><td>SonoSite (FujiFilm)</td><td>P16038</td><td></td></tr><tr><td>Low Frequency Ultrasound Probe (C35xp)</td><td>SonoSite (FujiFilm)</td><td>P19617</td><td></td></tr><tr><td>SonoSite X-porte Ultrasound</td><td>SonoSite (FujiFilm)</td><td>P19220</td><td></td></tr><tr><td>Ultrasound Gel</td><td>AquaSonic</td><td>PLI 01-08</td><td></td></tr></tbody></table>

identifying frailty using point-of-care ultrasonography: image acquisition and assessment

Frailty is a significant predictor of a range of adverse outcomes in surgical patients, including increased mechanical ventilation time, longer hospital stays, unplanned readmissions, stroke, delirium, and death. However, accessible tools for screening in clinical settings are limited. Computed tomography of the psoas muscle is the current standard imaging device for measuring frailty, but it is expensive, time-consuming, and exposes the patient to ionizing radiation. Recently, the use of point-of-care ultrasound (POCUS) has emerged as a potential tool to determine the presence of frailty and has been shown to accurately predict frailty and postoperative outcomes. In this article, we will describe the image acquisition of the quadriceps muscles and explain how they can be used to determine frailty and predict postoperative adverse events. We will present information on probe selection, patient positioning, and troubleshooting. Images from a demonstration will be used to present the POCUS technique and example results. The article will culminate in a discussion of the use of these images in medical decision-making and potential limitations.

By implementing this protocol for measuring quadriceps muscle thickness using real-time ultrasound, it is possible to accurately assess frailty indicators. Following the steps outlined in this protocol, we positioned the patient and selected the appropriate ultrasound probe for optimal visualization of the quadriceps muscles.
The key to success in this technique is the precise placement of the probe on the anterior thigh at approximately 60% the length from the ASIS to the superior border of the patella with the probe perpendicular to the long axis of the muscles23 (Figure 1). This allows for clear and distinct images of the quadriceps muscles, facilitating accurate measurements of muscle thickness, CSA, and circumference. The ultrasound images captured during this process (Figure 2) clearly demonstrate the muscle structures, providing a reliable basis for measurement.
It is crucial to note the potential for variability in muscle thickness measurements related to probe pressure. Excessive pressure can compress the muscle, leading to underestimation, while insufficient pressure may not adequately delineate the muscle borders, causing overestimation (Figure 5). Therefore, maintaining consistent probe pressure is essential to ensure the accuracy of the measurements. Consistent probe pressure can be obtained by applying even pressure perpendicular to the skin surface using visual feedback from the ultrasound image to maintain uniform pressure throughout the examination.
In addition to applying appropriate pressure, it is crucial to position the probe in the correct position on the anterior thigh. If the sonographic image reveals the sartorius muscle, the probe is placed too medial on the thigh, and it is necessary to scan more laterally until the entire thickness of the rectus femoris can be visualized (Figure 3D).
Moreover, probe selection can also affect the measurements. A low frequency curvilinear (2-5 MHz) or medium to high frequency linear probe (6-12 MHz) can be used depending on patient body habitus, probe availability, and provider preference. For patients with a larger body habitus25, or for patients with substantial muscle hypertrophy24, it is generally advised to use a lower frequency probe, which has a higher depth penetration but lower resolution24,25. Therefore, if adequate resolution cannot be obtained with a lower frequency probe, switching to a higher frequency probe may be considered to optimize visualization.
While it is recommended to obtain ultrasonographic measurements of both extremities, it is not required, especially in patients who may have malformations or deformities in one lower extremity. This approach helps to minimize unnecessary discomfort for the patient and allows for a more focused evaluation of the affected limb. Furthermore, many published imaging protocols suggest that the patient should be lying supine with their legs fully extended to obtain the image, but the patient may be more comfortable lying with their back or head elevated during the study. If necessary, the patient may also lie in a decubitus position.
To account for variations in muscle mass composition due to gender, body size, and obesity, the raw ultrasound measurements can be indexed by dividing by the body surface area (BSA) and body mass index (BMI) for normalization. This standardization allows for comparison across different individuals with varying body habitus and muscle ratios23.
In our sample subject, the measurements of quadriceps depth and rectus femoris CSA and circumference revealed a muscle thickness consistent with non-frail status according to frailty cutoffs described in Canales et al (men: 20.5 kg (body mass index less than 24), 21.5 kg (body mass index of 24 to 26) and 23 kg (body mass index greater than 26); women: 11.5 kg (body mass index less than 23) and 13 kg (body mass index greater than 23), indicating that the patient was not at a heightened risk for frailty-related complications in the perioperative setting. For contrast, observe the poor muscular integrity in a patient that would classify as frail (Figure 6B). In this sonograph, the scanner will note more heterogeneous echotexture and potentially interrupted fascial planes, suggesting reduced muscle mass and quality.
In summary, this case study illustrates the steps for using point-of-care ultrasound for quadriceps muscle thickness measurement in elderly patients. The technique&#39;s ability to provide real-time, accurate visualization of muscle structures makes it a valuable tool for frailty assessment in the perioperative setting.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66803/66803fig01.jpg" /> 
Figure 1: Anatomical landmarks for quadriceps muscle scanning. With the patient supine on the bed, identify the external landmarks including the anterior superior iliac spine (upper blue arrow), the superior border of the patella (lower blue arrow), and optimal probe placement location (red arrow). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66803/66803fig02.jpg" /> 
Figure 2: Ultrasonographic measurement of muscle anatomy. Once the appropriate cross-sectional image is ascertained (left),&#160;Use the calipers to measure the anterior-to-posterior distance between (1) the deep border of the vastus intermedius (just superficial to the cortex of the femur-green arrow) and (2) the most superficial fascia of the rectus femoris (red arrow). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66803/66803fig03.jpg" /> 
Figure 3: Ultrasonographic assessment of muscle anatomy. (A,B) A cross sectional orientation of subcutaneous tissue (SQ), rectus femoris (RF) muscle, and vastus intermedius (VI) muscle, with the sartorius highlighted in blue. The anterior surface of the femur is highlighted in purple. (C,D) The scans depicts the RF more medially to the SQ and VI muscles, indicating the need to adjust the probe to scan more laterally. Note that Panels C and D are the incorrect location to perform the measurement of the quadriceps muscle. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/66803/66803fig04v2.jpg" /> 
Figure 4:&#160;Ultrasonographic assessment of the Rectus Femoris (RF) muscle. (A) An incomplete visualization of the RF muscle, attributed to a superficial depth setting on the ultrasound device. (B) A complete visualization of the RF muscle, achieved by adjusting the depth setting to a deeper level. (C) The RF muscle with precise dimensions delineated: a cross-sectional area of 1.98 cm2 and a length measurement of 7.08 cm (orange arrow), as demarcated by the sonographic calipers.&#160; <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig04largev2.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/66803/66803fig05v2.jpg" /> 
Figure 5: Variability in ultrasonographic muscle thickness measurements due to probe pressure. (A,B) The panels demonstrate the potential for measurement discrepancies of the rectus femoris, with values ranging from 0.78 cm to 1.00 cm. (C,D) The panels demonstrate the potential for measurement discrepancy of the combined measurement of the entire quadriceps muscle (the sum of the rectus femoris and the vastus intermedius), with values ranging from 1.57 cm to 2.25 cm. Applying excessive pressure can yield erroneously small measurements; applying inadequate pressure can yield erroneously large measurements. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig05largev2.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/66803/66803fig06.jpg" /> 
Figure 6: Ultrasound scans of healthy versus frail individuals. (A) A scan from a healthy individual, characterized by a well-defined muscle with uniform echotexture and clear, continuous fascial planes, indicative of good muscle quality and volume. (B) A scan from an elderly frail individual, where the muscle appears less defined with a more heterogeneous echotexture and potentially interrupted fascial planes, suggests reduced muscle mass and quality, which are common findings associated with frailty. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/66803fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Supplementary Video 1: A different movement pattern of the rectus femoris compared to the deeper vastus muscles. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66803/jove frailty video.zip" target="_blank">Please click here to download this File.</a>

Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Here, we present a protocol to assess frailty in the perioperative setting using point-of-care ultrasound to measure quadriceps thickness. This method offers a practical, non-invasive alternative to traditional assessment methods, potentially enhancing perioperative care by quickly identifying frail patients.

Identifying Frailty Using Point-of-Care Ultrasonography: Image Acquisition and Assessment

Frailty is a significant predictor of a range of adverse outcomes in surgical patients, including increased mechanical ventilation time, longer hospital ...

identifying-frailty-using-point-care-ultrasonography-image

Universidad San Sebastian

Research

JoVE Journal

Medicine

470 Views.  George Washington University. Here, we present a protocol to assess frailty in the perioperative setting using point-of-care ultrasound to measure quadriceps thickness. This method offers a practical, non-invasive alternative to traditional assessment methods, potentially enhancing perioperative care by quickly identifying frail patients.

Video: Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood

There is the need for a clinical assay to determine the extent to which a patient's blood is effectively anticoagulated by the low-molecular-weight-heparin (LMWH), enoxaparin. There are also urgent clinical situations where it would be important if this could be determined rapidly. The present assay is designed to accomplish this. We only assayed human blood samples that were spiked with known concentrations of enoxaparin. The essential feature of the present assay is the quantification of the efficacy of enoxaparin in a patient's blood sample by degrading it to complete inactivity with heparinase. Two blood samples were drawn into Vacutainer tubes (Becton-Dickenson; Franklin Lakes, NJ) that were spiked with enoxaparin; one sample was digested with heparinase for 5 min at 37 &deg;C, the other sample represented the patient's baseline anticoagulated status. The percent shortening of clotting time in the heparinase-treated sample, as compared to the baseline state, yielded the anticoagulant contribution of enoxaparin. We used the portable, battery operated Hemochron 801 apparatus for measurements of clotting times (International Technidyne Corp., Edison, NJ). The apparatus has 2 thermostatically controlled (37 &deg;C) assay tube wells. We conducted the assays in two types of assay cartridges that are available from the manufacturer of the instrument. One cartridge was modified to increase its sensitivity. We removed the kaolin from the FTK-ACT cartridge by extensive rinsing with distilled water, leaving only the glass surface of the tube, and perhaps the detection magnet, as activators. We called this our minimally activated assay (MAA). The use of a minimally activated assay has been studied by us and others. 2-4 The second cartridge that was studied was an activated partial thromboplastin time (aPTT) assay (A104). This was used as supplied from the manufacturer. The thermostated wells of the instrument were used for both the heparinase digestion and coagulation assays. The assay can be completed within 10 min. The MAA assay showed robust changes in clotting time after heparinase digestion of enoxaparin over a typical clinical concentration range. At 0.2 anti-Xa I.U. of enoxaparin per ml of blood sample, heparinase digestion caused an average decrease of 9.8% (20.4 sec) in clotting time; at 1.0 I.U. per ml of enoxaparin there was a 41.4% decrease (148.8 sec). This report only presents the experimental application of the assay; its value in a clinical setting must still be established.

Demonstration of a rapid quantitative assay of the inhibition of blood coagulation by the low-molecular-weight-heparin, enoxaparin. The contribution of enoxaparin is assessed by removing its influence through digestion with heparinase. A fuller description of the assay is detailed in our published paper.1 The assay still requires clinical confirmation.

There is the need for a clinical assay to determine the extent to which a patient's blood is effectively anticoagulated by the ...

Measuring Frailty in HIV-infected Individuals. Identification of Frail Patients is the First Step to Amelioration and Reversal of Frailty

A simple, validated protocol consisting of a battery of tests is available to identify elderly patients with frailty syndrome. This syndrome of decreased reserve and resistance to stressors increases in incidence with increasing age. In the elderly, frailty may pursue a step-wise loss of function from non-frail to pre-frail to frail. We studied frailty in HIV-infected patients and found that ~20% are frail using the Fried phenotype using stringent criteria developed for the elderly1,2. In HIV infection the syndrome occurs at a younger age.
HIV patients were checked for 1) unintentional weight loss; 2) slowness as determined by walking speed; 3) weakness as measured by a grip dynamometer; 4) exhaustion by responses to a depression scale; and 5) low physical activity was determined by assessing kilocalories expended in a week's time. Pre-frailty was present with any two of five criteria and frailty was present if any three of the five criteria were abnormal.
The tests take approximately 10-15 min to complete and they can be performed by medical assistants during routine clinic visits. Test results are scored by referring to standard tables. Understanding which of the five components contribute to frailty in an individual patient can allow the clinician to address relevant underlying problems, many of which are not evident in routine HIV clinic visits.

Frailty syndrome is commonly seen in the aged and reflects multi-system physiological change. However, with reduced functional reserve and resilience frailty is also known to be common in the HIV infected population. This study outlined an easily administered screening test to identify HIV patients with frailty. When significant components of frailty are identified, clinicians will be able to focus on amelioration of the problem and promote reversion to the pre-frail state.

A simple, validated protocol consisting of a battery of tests is available to identify elderly patients with frailty syndrome. This syndrome of decreased ...

Ultrasonic Assessment of Myocardial Microstructure

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. Ultrasonic assessments of cardiac tissue can include analyses of backscatter signal intensity within a given region of interest. Previously established techniques have relied predominantly on the integrated or mean value of backscatter signal intensities, which may be susceptible to variability from aliased data from low frame rates and time delays for algorithms based on cyclic variation. Herein, we describe an ultrasound-based imaging algorithm that extends from previous methods, can be applied to a single image frame&#160;and accounts for the full distribution of signal intensity values derived from a given myocardial sample. When applied to representative mouse and human imaging data, the algorithm distinguishes between subjects with and without exposure to chronic afterload resistance. The algorithm offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Echocardiography is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. We describe an ultrasound-based imaging algorithm that offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and ...

Cortical Bone Assessment Using the Ultrasonic BDAT Device

Cortical Bone Assessment Using Ultrasonic Guided Waves: A Reproducibility Study in a Healthy Population

Fragility fractures are still a worldwide health burden in the context of population aging. In particular, the global number of hip fractures is expected to double between 2020 and 2050. Therefore, it is essential to detect patients at risk of fragility fracture at the population scale. The current golden standard is dual X-ray absorptiometry (DXA), providing the areal bone mineral density (aBMD). Ultrasonic devices, usually more portable and cheaper than X-ray devices, represent interesting DXA alternatives as screening tools. However, operator dependency is usually recognized as their main drawback. In this study, the measurement protocol of the bi-directional axial transmission (BDAT) ultrasonic device is presented in detail. The dedicated ultrasonic probe is placed at the one-third distal radius of the non-dominant forearm using conventional coupling gel. The guided interface provides in quasi-real time (about 2 Hz) four parameters of interest: velocities of the first arriving signal (vFAS) and the A0 mode (vA0),&#160;cortical thickness (Ct.Th) and porosity (Ct.Po), as well as four quality parameters. The operator moves the probe slowly at the measurement site, carefully observing the feedback provided by the interface until finding a stable position and starting a series of 10 acquisitions. When at least four consistent series are obtained, the measurement ends, and an automatic report is generated. The measurement usually takes about 5 min to complete. To determine the robustness of this protocol, a reproducibility study was conducted among 3 operators (one expert and two novices) and 14 healthy participants (6 women, 8 men, 21-53 years old). The intraclass correlation coefficients (ICC) were found good for vA0 (0.76), Ct.Po (0.80) or excellent for Ct.Th (0.87) and vFAS (0.91). The standard deviations were found to be less than 10% of the total ranges in clinical practice.

Here, we present the measurement protocol of the bi-directional axial transmission (BDAT) ultrasonic device in detail and test it in a reproducibility study, considering 14 healthy participants and 3 operators. Reliability, measured with the intraclass correlation coefficients (ICC), was good to excellent for four parameters of interest.

Fragility fractures are still a worldwide health burden in the context of population aging. In particular, the global number of hip fractures is expected ...

Bioengineering

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 ...

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 ...

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

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

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

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

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

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

POCUS Protocol for IVC Assessment in Management of Heart Failure

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

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

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

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

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

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.

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.

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