SonoStudy: Emergency docs detect small bowel obstruction by US – as good as radiologists #FOAMed

In a recent article in the European Journal of Emergency medicine, the authors showed that emergency physicians are just as good as radiologists in detecting small bowel obstruction by bedside US. Now, it’s not hard to do, nor is it hard to see it. First off, use your abdominal low frequency probe, and evaluate the abdomen in different quadrants. Normally, the bowel appears as a single circular hypoechoic layer (muscle layer) surrounding hyperechoic bowel contents of gas and food particles. The normal thickness of this layer during the contraction stage of peristalsis is 2-3 mm. The hypoechoic normal wall becomes thinner during peristalsis when the bowel is relaxed.

In small bowel obstruction- looking for dilated fluid filled loops of bowel with hyperechoic (bright) spots within it that may have back and forth peristalsis and a thicker intestinal wall (decreased persitalsis is a late finding) – color doppler gives info about blood flow in the walls of the intestine – and you may even see a transition point. Timothy Jang and team studied ultrasound compared to Xray for SBO and found that ultrasound is better, like WAYYYY better (higher sensitivity and specificity) – hmmm, interesting – Some things to consider: fluid-filled loops (good for US), but air-filled loops may not be so good. Ileus and SBO may appear similarly, so consider thinking of causes of ileus as well (gallstone ileus, etc), and a thickened wall may just be colitis, but that along with dilated loops and back and forth persitalsis with a transition point seen – more likely SBO.

This is what it would look like (and there are more clips to view – thanks to SonoCloud)

The abstract of the study follows:

“Objective: Our objective was to study the accuracy of emergency medicine [(EM) bedside ultrasonography (BUS)] and radiology residents performed ultrasonography (RUS) in patients with suspected mechanical small bowel obstruction (SBO).

Methods: After a 6-h training program, from January to June 2009, four EM residents used BUS to prospectively evaluate the patients presenting to the emergency department with suspected SBO. Then, patients underwent RUS. Outcome was determined by surgical findings if they were operated upon or self-reported the condition upon telephone follow-up at 1-month. BUS and RUS results were compared with χ2 testing.

Results: Of the 174 enrolled patients, 90 patients were BUS-positive. Of these, surgical findings agreed with the BUS findings in 84 patients. In 78 cases, BUS was negative, and 76 of these patients had benign clinical courses. Six patients were excluded from the study. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for BUS were 97.7, 92.7, 93.3, 97.4, and 13.4%, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value for RUS were 88.4, 100, 100, and 89.1%, respectively. The diagnostic accuracy of BUS and RUS were not statistically different from each other (κ=0.81). The presence of dilated small bowel loops (>25 mm in jejunum or >15 mm in ileum) was the most sensitive (94%) and specific (94%) sonographic finding for SBO.

Conclusion: Abdominal sonography for the diagnosis of SBO is a new application of BUS in the emergency department. EM residents can diagnose SBO using BUS with a high-degree of accuracy, comparable with that of radiology residents.”

To read the UltrasoundPodcast guys speak on the subject, click here>

To see them do it, see below:

SonoLectures: Free lecture on Ultrasound in the Critically Ill -by Dr. Cliff Rice (& other free lectures)

Got an email from ACEP and thought it was too good not to share: Hear Dr. Cliff Rice, an ultrasound extraordinaire and emergency physician speak about bedside ultrasound and its use in critical care medicine. At the end of this post are even more lectures that are free. As you will hear, he states “Think about how you would use it in some of our sickest patients that come to the emergency department….. where the differential diagnosis is quite broad, and the treatment for shock might be detrimental if we are wrong.”

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As ACEP states in the email: “Practicing emergency physicians need to be able to utilize ultrasound effectively in the evaluation of the critically ill patient. In this free audio recording from the 2012 ACEP Scientific Assembly, Dr. Rice highlights the use of ultrasound to perform a FAST scan, to dynamically monitor and measure the IVC in the setting of hypovolemic shock, and to detect pericardial effusion and perform ultrasound guided pericardiocentesis [in 45 minutes]. This [lecture] explains where you should start scanning, narrows your differential and guides your resuscitation.”

Other free lectures for your viewing/hearing pleasure on bedside ultrasound:

Dr. Chris Fox’s comprehensive emergency ultrasound lectures in iTunes

Dr. Phil Perera comprehensive emergency ultrasound lectures on Sound-Bytes

AIUM UltrasoundFirst lecture series on various ultrasound topics

UltrasoundPodcast with a variety of lectures on bedside ultrasound

UltrasoundVIllage website on a variety of ultrasound topics

Vanderbilt’s excellent lectures library on bedside ultrasound

SonoCase from EPMonthly: 19 yr old with food poisoning? hmm….by B. Pregerson and T. Wu

Merry Christmas everyone! For your reading pleasure this week, Id thought we would discuss a case whose topic is near and dear to my heart. In the most recent issue of EPMonthly, there is a great case and interesting “internal” discussion made quite humorously public by Drs. Pregerson and T. Wu of a young healthy male with right lower quadrant abdominal pain after eating at a “Roach Coach”…. which just so happen to have the best breakfast burritos, but I digress… The case discussion involves how the history and physical may help, how labs may (or may not) help and how an ultrasound can be of use to make you and your surgical colleagues feel better in taking the patient to the OR. There was a recent post on SonoSpot about ultrasound in appendicitis sharing data from a study about the CT findings when US “equivocal” cases arise.  When the ultrasound is positive – how great is that?! Quite a few studies recently on the topic and some of the more recent ones can be found here.

The case is followed by an extensive (and great) discussion of the technique, pearls and pitfalls of ultrasound in evaluating the appendix – because we all know there are quite a few. As far as the sensitivity ad specificity go, they state it best:

“Sensitivity & Specificity: Both the sensitivity & specificity of ultrasound for appendicitis are less than that of CT. In pediatrics the values are about 88% and 94% respectively, and in adults about 83% and 93%. (These numbers may vary depending on the experience of the ultrasonographer.) There are studies from Europe and Israel where they have used the “ultrasound first” approach for many, many years that show even better test characteristics. These values are actually not that bad when compared to CT scan whose sensitivity and specificity are around 94% and 95% respectively. Remember, however, that the performance characteristics for ultrasound can be significantly worse in overweight patients or those with overlying bowel gas. In addition, if the appendix is retrocecal or is lying in a difficult anatomical plane, the study will be more challenging.  Unfortunately, you may still have to do a CT scan if your ultrasound is non-diagnostic and your clinical suspicion is moderate to high, but the strategy of ultrasound first would likely decrease CTs by about 50%.”

And in kids…”You should be aware of the most recent recommendation of the American College of Radiology from the “Choosing Wisely” campaign, which states, “Don’t do computed tomography (CT) for the evaluation of suspected appendicitis in children until after ultrasound has been considered as an option.” Although CT is accurate in the evaluation of suspected appendicitis in the pediatric population, ultrasound is nearly as good in experienced hands. Since ultrasound will reduce radiation exposure, ultrasound is the preferred initial consideration for imaging examination in children. If the results of the ultrasound exam are equivocal, it may be followed by CT. This approach is cost-effective, reduces potential radiation risks and has excellent accuracy, with reported sensitivity and specificity of 94 percent.”

To diagnose appendicitis: look for a noncompressible a-peristaltic structure that attaches to the cecum that is larger than 7mm in diameter.

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A great tutorial of ultrasound for the appendix can be found here by the UltrasoundPodcast guys:

SonoStudy and Tutorial: EPSS vs fractional shortening for LV function – is EPSS good enough?

In a recent issue of the Journal of Ultrasound through AIUM, Weekes et al. (and Kendall et al in AM J EM) talk about a hot topic that emergency and critical care physicians hold dear to them – the EPSS , or E-point septal separation – the minimal distance between the anterior mitral valve leaflet and the interventricular septum in the parasternal long view of the cardiac echo during diastole using M-Mode. Now, EPSS is not a part of point of care echo right now (i know, phew!), but there are conversations about whether it should be. The reason is because it is thought that EPSS is a good tool for LV function delineation, possibly better than simple visualization, despite knowing the risks of underestimating ejection fraction due to endocardial output limitations (see below). …Yeah, I know, that’s a lot of words and it took me a year to really understand what the above meant. So, let’s talk about it…especially as it is included in the updated RUSH protocol by Seif, Perera, et al.

EPSS by echo has even been compared to cardiac MRI for LV function recently. And, Dr. Mike Stone and friends did a study last year with regard to EPSS compared to qualitative LV function, stating: “Dyspneic patients with acute decompensated heart failure (ADHF) often present to the emergency department (ED), and emergency physicians (EPs) must act quickly and accurately to evaluate and diagnose patients with ADHF. Traditionally, key components of the patient’s history, physical examination, electrocardiography, and chest radiography are used to diagnose ADHF. However, no single test is highly accurate, and even with the incorporation of B-type natriuretic peptide levels, the diagnosis of ADHF in a dyspneic patient in the ED can be a challenge. Additional modalities that allow prompt and accurate diagnosis of ADHF would be of clinical utility, and estimation of left ventricle ejection fraction (LVEF) using point-of-care ultrasound has been the focus of prior research” showing that EPSS is a good tool compared to qualitative LVEF visualization. EM News folks also highlighted EPSS in a recent entry.

Now, lets talk a bit about the anatomy and physiology about this before we talk about the study. The mitral valve has an anterior leaflet and a posterior leaflet. You can see the mitral valve open and close in the parasternal long view of the heart. the below picture indicates the anterior leaflet:

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Using the Cardiovscular Institute’s diagrams, we can see the functioning of the mitral valve during systole and diastole in relation to the EKG, with every movement /peaks delineated with a letter  ….one of them being “e” (where E of EPSS comes from):

Screen shot 2012-12-14 at 10.46.50 AMScreen shot 2012-12-14 at 10.48.15 AM

…and in relation to the EKG on M-mode on the PSL view (aka motion mode – basically visualizing the motion of objects in time).

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EPSS of >7mm is thought to be an indication of poor LV function. Some use 1cm as the mark to increase their sensitivity for low ejection fraction. So, you can see that it should be a good indicator of LV function.

Fractional shortening (FS), however, is….(LVEDd-LVESd) / LVEDd expressed as a percentage. Placing the M-mode cursor across the LV just beyond the mitral valve leaflets, a tracing is shown whose measurements of the LV chamber diameter in both systole and diastole can illustrate FS, or LV contractility (not ejection fraction as it is not a volume measurement). Normal FS being 30-45%. For a complete description of these terms go here – a great overview by ICU Sonography –  and here – a simpler way to understand the measurements through the Stanford ICU website. The updated RUSH protocol, also explains this well, with images from their most recent publication below:

Hyperdynamic/hypercontractile: FS >45%

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Abnormal: hypocontractile LV: FS<30%

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So, the study was a prospective study, thankfully, and seemed to really want EPSS to be good for LV function, but it looks like it’s not as good as we think:

Abstract: “Objectives Rapid bedside assessment of left ventricular (LV) function can aid in the evaluation of the critically ill patient and guide clinical management. Our primary hypothesis was that mitral valve E-point septal separation measurements would correlate with contemporaneous fractional shortening measurements of LV systolic function when performed by emergency physicians. Our secondary hypothesis was that E-point septal separation as a continuous variable would predict fractional shortening using a linear regression model.

Methods We studied a prospective convenience sample of patients undergoing a sequence of LV systolic function measurements during a 3-month period at a suburban academic emergency department with a census of 114,000 patients. The sample included adult emergency department patients who were determined by the treating emergency physician to have 1 or more clinical indications for bedside LV systolic function assessment. Investigators performed bedside M-mode cardiac sonographic measurements of fractional shortening and E-point septal separation using the parasternal long-axis window. The sequence of LV systolic function measurements was randomized.

Results A total of 103 patients were enrolled. The Pearson correlation coefficient for E-point septal separation and fractional shortening measurements was –0.59 (P< .0001). Linear regression analysis performed for E-point septal separation with fractional shortening as the dependent variable yielded an R2 value of 0.35.

Conclusions E-point septal separation and fractional shortening measurements had a moderate negative correlation. E-point septal separation, when used as a continuous variable in a linear regression model, did not reliably predict fractional shortening.”

The limitations of EPSS as discussed in Stone’s paper:

Valvular diseases that restrict anterior mitral leaflet motion ( mitral stenosis, aortic insufficiency) – will exaggerate EPSS.

Asymmetric septal hypertrophy,

Severe left ventricular hypertrophy,

Discrete proximal septal thickening (sigmoid septum) can lead to small
estimates of EPSS.

Failure to obtain a true parasternal long-axis view may result in falsely elevated
EPSS measurements due to a tangential measurement from mitral valve leaflet to septal wall.

….At the end of the day, my opinion -> just visualizing the LV contractility, as long as you have a good PSL and PSS long view, and you’ve seen enough to know normal versus abnormal, is good enough for me!

SonoProcedures: Review of ultrasound-guided procedures, technique, and videos

In the most recent addition of Emergency Medicine Clinics of North America (yup, you’ll need to register to view), some big wigs in bedside ultrasound (Tirado, Teresa Wu, Resa Lewiss, Vicki Noble, Adam Sivitz) published an article reviewing the ultrasound – guided techniques (with images) of procedures where an ultrasound machine can make all the difference in decreasing complications, increasing patient satisfaction, and decreasing time of procedure. From pericardiocentesis, thoracentesis, abscess drainage to lumbar puncture, arthrocentesis, and foreign body removal, these physicians discuss it all. “Bedside ultrasound is an extremely valuable and rapidly accessible diagnostic and therapeutic modality in potentially life- and limb-threatening situations in the emergency department. In this report, the authors discuss the role of ultrasound in quick assessment of pathologic conditions and its use to aid in diagnostic and therapeutic interventions”

In the same issue, Drs. Tirado, Nagdev and others discuss ultrasound-guided venous central and peripheral venous access and nerve blocks (a topic near and dear to Arun Nagdev’s heart – given how many publications he has done on the topic – a true expert!). “Ultrasound has rapidly become an essential tool in the emergency department, specifically in procedural guidance. Its use has been demonstrated to improve the success rate of procedures, while decreasing complications. In this article, we explore some of these specific procedures involving needle guidance and structure localization with ultrasound.”

And, in the same issue, Drs. Lewis, Crapo, and Williams discuss more procedural guidance using bedside ultrasound for central venous access as well as a review of other procedures, like IO lines an arterial lines. “The venous and/or arterial vasculature may be accessed for fluid resuscitation, testing and monitoring, administration of blood product or medication, or procedural reasons, such as the implantation of cardiac pacemaker wires. Accessing the vascular system is a common and often critically important step in emergency patient care. This article reviews methods for peripheral, central venous, and arterial access and discusses adjunct skills for vascular access such as the use of ultrasound guidance, and other forms of vascular access such as intraosseus and umbilical cannulation, and peripheral venous cut-down. Mastery of these skills is critical for the emergency medicine provider.”

A great review of pericardiocentesis, thoracentesis, paracentesis, vascular access, foreign body localization, abscess drainage, and nerve blocks can be found on Sonoguide as well.

Here are some great videos on how-to perform the varying procedures:

Pericardiocentesis:

Thoracentesis:

Paracentesis:

Abscess drainage:

Central venous access: internal jugular

Central venous access – supraclavicular approach to the subclavian vein:

Ultrasound Podcast on the Subclavian and Supraclavicular venous access in only the way they know how.

Central venous access – axillary vein cannulation

Peripheral venous access:

A great video on US guided Peripheral IV can be found here, by HQMedEd

Lumbar puncture:

Foreign Body removal:

Femoral nerve block:

Axillary Nerve block:

Distal Sciatic nerve block:

Nerve blocks of all kinds can be found here on SonicNerve.

Other procedures:

US guided fracture reduction

 

SonoTutorial: Musculoskeletal Ultrasound of the Tendon – an AIUM Sound Judgement Series

In the recent entry of the Journal of Ultrasound in Medicine, Dr. Ken Lee (MSK radiology), discusses how ultrasound of the tendon can add to your clinical work up of a patient with pain in that area. it is the most common sports-related injury and we see it in the emergency department all.the.time.  In a prior post, we highlighted how Dr. Brita Zaia evaluated a patient with knee pain and tenderness who came to the ED for an arthrocentesis, showing the patellar tendon abnormality on her ultrasound image, making her diagnosis without the need of that invasive procedure (Published in WestJEM).

“Common tendon abnormalities include tendinopathy and tendon tears, which impose a substantial cost to society in the United States and abroad. According to the American Public Health Association, tendon disorders account for approximately $850 billion per year in health care costs and indirect lost wage expenditures.4 Accurate and timely diagnosis of musculoskeletal tendon injuries is critical to ensure proper treatment and thus minimize societal costs. Magnetic resonance imaging (MRI) has been the imaging standard for musculoskeletal injuries. However, MRI is costly and overused.5 Improvements in ultrasound technology have made sonography a rapidly growing imaging alternative and complementary tool to MRI for the diagnosis of common tendon injuries.6…..The most defining advantage of sonography over MRI is its real-time imaging capability, which allows for dynamic evaluation of the tendon using a variety of stress maneuvers.16,17 For example, in the neutral position, the long head of the biceps tendon may lie normally in the bicipital groove (Figure 3), only to dislocate medially once the arm, with elbow flexed, is externally rotated (Figure 4). In addition to tendon subluxation, other tendon abnormalities diagnosed dynamically include tendon snapping, friction between two structures such as in shoulder impingement,18 and increasing conspicuity of tendon tears while stressing the tendon or with sonopalpation.17 Real-time dynamic sonographic evaluation provides this unique diagnostic ability using controlled movements.”

Read more in this article to learn about what it means and what happens when the tendon goes from looking like this:

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..to looking like this:

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or like this….

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with plenty more examples of it, illustrating how awesome it is and why we should use bedside ultrasound to evaluate tendons more.

SonoStudy: US-guided lines by nurses (& docs) reduce need for physician intervention (& central lines!) for difficult access

A recent study, from the Journal of Emergency Medicine, by Weiner et al at Tufts University, in addition to so many of the prior studies, proves that nurses SHOULD perform ultrasound guided peripheral line placement. they are good at it, they do it right, and they do it well. Oh, and patients love it.

“Emergency physicians (EPs) have become facile with ultrasound-guided intravenous line (USIV) placement in patients for whom access is difficult to achieve, though the procedure can distract the EP from other patient care activities…..A prospective multicenter pilot study: Interested emergency nurses (ENs) received a 2-h tutorial from an experienced EP. Patients were eligible for inclusion if they had either two failed blind peripheral intravenous (i.v.) attempts, or if they reported or had a known history of difficult i.v. placement. Consenting patients were assigned to have either EN USIV placement or standard of care (SOC).” 50 patients enrolled, 29 assigned to USIV and 21 to SOC. “Physicians were called to assist in 11/21 (52.4%) of SOC cases and 7/29 (24.1%) of USIV cases (p = 0.04). Patient satisfaction was higher in the USIV group, though the difference did not reach statistical significance (USIV 86.2% vs. SOC 63.2%, p = 0.06). “

And, even more recently, another study:

Ultrasound-Guided Peripheral Intravenous Access Program Is Associated With a Marked Reduction in Central Venous Catheter Use in Noncritically Ill Emergency Department Patients.

by Shokoohi et al from George Washington University published in the Annals of Emergency Medicine has been getting quite a bit of press – particularly from MedwireNews: “Training emergency department (ED) staff in use of ultrasound to guide difficult peripheral intravenous catheter placement appears to reduce the unnecessary use of central venous lines, a study suggests. The reduction in central venous line use after the introduction of ultrasound training was particularly notable for patients who were not critically ill, report Hamid Shokoohi (George Washington University, DC, USA) and colleagues…..They say that this has “potentially major implications for patient safety,” noting that around 15% of the 5 million central venous catheters placed in the USA annually result in complications, which can include blood infections, thrombosis, vessel damage, and hematomas.”

The study itself was: “….a time-series analysis of the monthly central venous catheter rate among adult emergency department (ED) patients in an academic urban ED between 2006 and 2011. During this period, emergency medicine residents and ED technicians were trained in ultrasound-guided peripheral intravenous access. We calculated the monthly central venous catheter placement rate overall and compared the central venous catheter reduction rate associated with the ultrasound-guided peripheral intravenous access program between noncritically ill patients and patients admitted to critical care. Patients receiving central venous catheters were classified as noncritically ill if admitted to telemetry or medical/surgical floor or discharged home from the ED. RESULTS: During the study period, the ED treated a total of 401,532 patients, of whom 1,583 (0.39%) received a central venous catheter. The central venous catheter rate decreased by 80% between 2006 (0.81%) and 2011 (0.16%). The decrease in the rate was significantly greater among noncritically ill patients (mean for telemetry patients 4.4% per month [95% confidence interval {CI} 3.6% to 5.1%], floor patients 4.8% [95% CI 4.2% to 5.3%], and discharged patients 7.6% [95% CI 6.2% to 9.1%]) than critically ill patients (0.9%; 95% CI 0.6% to 1.2%). The proportion of central venous catheters that were placed in critically ill patients increased from 34% in 2006 to 81% in 2011 because fewer central venous catheterizations were performed in noncritically ill patients. CONCLUSION: The ultrasound-guided peripheral intravenous access program was associated with reductions in central venous catheter placement, particularly in noncritically ill patients. Further research is needed to determine the extent to which such access can replace central venous catheter placement in ED patients with difficult vascular access.”

A great video on the scanning technique and choosing the right vein can be found here by SonoSite and taught by my good friend, Diku Mandavia:

Another great how-to video can be found here: although long, its a good one for a step-by-step, from the New England Journal of Medicine: