SonoStudyReview: The Pneumothorax by @EMLyceum – EBM review on imaging/diagnosis/treatment #FOAMed

If there ever was a post worth reading about pneumothorax, this excellent review by EM Lyceum was too good not to pass along to everyone. Now I don’t know about you, but I always get asked the questions about chest Xray versus Ultrasound, what to do when only the ultrasound shows the pneumothorax (because you know it’s better than Chest Xray! as discussed in a prior post), when to order that CT chest, and how should you treat it: nothing? pigtail? small chest tube? large chest tube? EM Lyceum does a great job in reviewing this using literature to back it up. There have been more studies that haven’t been mentioned with regard to ultrasound and pneumothorax diagnosis, and the sensitivity and specificity of chest xray is stated pretty high as prior studies tend to do (with more accurate and recent ones stated by EM Lyceum to be lower (in the real world that we work in). And, there was a great meta-analysis in Chest Journal speaking of which imaging modality was better, chest Xray or ultrasound. Go to the EM Lyceum site and read-on to grasp the answers to all the questions! Thank you EM Lyceum – this was awesome!

By BTS 2010 guidelines (Macduff, 2010).

SonoStudy: Thoracic ultrasound in identifying pneumothorax progression in the intubated – the lung point

In the Feb 2013 issue of Chest, Oveland et al studied porcine models, introducing air at incremental levels to identify if thoracic ultrasound is as accurate as CT scanning for the detection pneumothorax progression in the intubated patient. They found that “the accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation.”

“Background:  Although thoracic ultrasonography accurately determines the size and extent of occult pneumothoraces (PTXs) in spontaneously breathing patients, there is uncertainty about patients receiving positive pressure ventilation. We compared the lung point (ie, the area where the collapsed lung still adheres to the inside of the chest wall) using the two modalities ultrasonography and CT scanning to determine whether ultrasonography can be used reliably to assess PTX progression in a positive-pressure-ventilated porcine model.

Methods:  Air was introduced in incremental steps into five hemithoraces in three intubated porcine models. The lung point was identified on ultrasound imaging and referenced against the lateral limit of the intrapleural air space identified on the CT scans. The distance from the sternum to the lung point (S-LP) was measured on the CT scans and correlated to the insufflated air volume.

Results:  The mean total difference between the 131 ultrasound and CT scan lung points was 6.8 mm (SD, 7.1 mm; range, 0.0-29.3 mm). A mixed-model regression analysis showed a linear relationship between the S-LP distances and the PTX volume (P < .001).

Conclusions:  In an experimental porcine model, we found a linear relation between the PTX size and the lateral position of the lung point. The accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation.”

Full article found here.

To see the lung point, you visualize the pleural line using the linear probe (indicator toward the patient’s head) starting from anterior chest wall (2nd intercostal space, mid-clavicular line) to inferior-lateral chest wall, and look out for the area where the lack of lung sliding or comet tail artifacts reverts back to normal lung sliding with comet tail artifacts. Blaivas, et al, studied this, showing that bedside ultrasound can detect size of pneumothorax through identification of the lung point location. Below is a video fo the lung point:

lung_point_2_crop

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SonoStudy & Review of literature: Rapid Lung/cardiac/IVC – differentiates causes of acute dyspnea

A recent study in cardiovascular medicine … a concept that has been highlighted in varying ways from prior studies (by Liteplo (ETUDES study), Lichtenstein (all of his studies, actually), Volpicelli (ILC-LUS international consensus), and Manson with the RADIUS study/protocol), continues to conclude that rapid bedside ultrasound of lung/cardiac/IVC can help differentiate causes of acute dyspnea. The state: “The present study demonstrated that rapid evaluation by lung-cardiac-inferior vena cava (LCI) integrated ultrasound has a higher diagnostic accuracy for differentiating acute dyspnea due to AHFS from pulmonary acute dyspnea (including COPD/asthma, pulmonary fibrosis, and ARDS) compared with lung ultrasound either alone or in combination with plasma BNP assay. These findings suggest that LCI integrated ultrasound has become a fundamental tool for diagnostic evaluation of patients with acute dyspnea and selection of early treatment in the emergency setting.”

The algorithm below is what they used:

ABSTRACT:

BACKGROUND: Rapid and accurate diagnosis and management can be lifesaving for patients with acute dyspnea. However, making a differential diagnosis and selecting early treatment for patients with acute dyspnea in the emergency setting is a clinical challenge that requires complex decision-making in order to achieve hemodynamic balance, improve functional capacity, and decrease mortality. In the present study, we examined the screening potential of rapid evaluation by lung-cardiac-inferior vena cava (LCI) integrated ultrasound for differentiating acute heart failure syndromes (AHFS) from primary pulmonary disease in patients with acute dyspnea in the emergency setting.

METHODS:

Between March 2011 and March 2012, 90 consecutive patients (45 women, 78.1 +/- 9.9 years) admitted to the emergency room of our hospital for acute dyspnea were enrolled. Within 30 minutes of admission, all patients underwent conventional physical examination, rapid ultrasound (lung-cardiac-inferior vena cava [LCI] integrated ultrasound) examination with a hand-held device, routine laboratory tests, measurement of brain natriuretic peptide, and chest X-ray in the emergency room.

RESULTS:

The final diagnosis was acute dyspnea due to AHFS in 53 patients, acute dyspnea due to pulmonary disease despite a history of heart failure in 18 patients, and acute dyspnea due to pulmonary disease in 19 patients. Lung ultrasound alone showed a sensitivity, specificity, negative predictive value, and positive predictive value of 96.2, 54.0, 90.9, and 75.0%, respectively, for differentiating AHFS from pulmonary disease. On the other hand, LCI integrated ultrasound had a sensitivity, specificity, negative predictive value, and positive predictive value of 94.3, 91.9, 91.9, and 94.3%, respectively.

CONCLUSIONS:

Our study demonstrated that rapid evaluation by LCI integrated ultrasound is extremely accurate for differentiating acute dyspnea due to AHFS from that caused by primary pulmonary disease in the emergency setting.

SonoStudy: Prehospital Chest Ultrasound matters!

In a recent study published in Journal of Emergency Medicine, there is a high powered study with quite a few patients on whether prehospital chest ultrasound changes management, destination, or intervention. Once again, a great study highlighting how point of care ultrasound should be used by prehospital providers.

“BACKGROUND:

Due to advancements in technology, the use of a portable ultrasound (US) machine in the out-of-hospital setting is increasingly feasible. It has diagnostic and therapeutic advantages and may improve the management and treatment of patients. It can be used in-flight and can be easily taught to flight clinicians who have little previous experience with this modality.

STUDY OBJECTIVES:

The goal of this study was to evaluate the impact of ultrasound chest examinations on the care of patients treated by a Helicopter Emergency Medical Service (HEMS).

METHODS:

Since 2007, portable US has been used by the HEMS of Nijmegen, The Netherlands. Data on every air medical flight are routinely collected in a database. Every portable US examination of the chest performed between 2007 and 2010 was reviewed for this study. Data on patient characteristics, properties of US examinations, US diagnoses, and impact on medical treatment were collected and analyzed.

RESULTS:

Of a total of 2572 patients, 326 portable US examinations of the chest were performed on 281 (11%) patients. The mean duration of a portable US examination was 2.77 (SD 1.30) min, and the duration decreased over time. After the US examination, the plan for treatment changed in 60 (21%) patients. In 10 patients (4%) the plan to place a chest tube was abandoned. In 10 patients (4%) the initially selected destination for definitive care changed, and it changed to a lower-level hospital more often than to a higher-level one. In 9 patients (3%), cardiopulmonary resuscitation was stopped and in 31 patients there were other changes.

CONCLUSION:

Out-of-hospital US examinations can alter and improve treatment decisions and destinations for definitive care.”

SonoStudy: Ultrasound can diagnose pediatric pneumonia! – Quite a lot of press on this topic!

Not that thoracic bedside ultrasound is only good for children’s pneumonia – as we know there have been recent articles ….and posts here on SonoSpot summarizing the recent hot topic (including one from Blaivas from the Journal of US in Medicine, and another highlighted in our bi-annual Northern CA Journal Club) …that it can help in diagnosing adult pneumonia too – but this topic is getting quite a bit of press lately due to the affect of it with our kids in another study recently published – decreasing radiation? decreasing length of stay? decreasing cost? increasing satisfaction? yes, please.

The actual pediatric study (abstract) can be found here.  It states: just after 1 hour of clinicians learning how to do it, they were able to diagnose pneumonia with ultrasound (chest Xray used as a reference standard). 200 patients (!!) were studied with the prevalence of pneumonia by chest XRay was 18%. “Ultrasonography had an overall sensitivity of 86% (95% CI, 71%-94%), specificity of 89% (95% CI, 83%-93%), positive LR of 7.8 (95% CI, 5.0-12.4), and negative LR of 0.2 (95% CI, 0.1-0.4) for diagnosing pneumonia by visualizing lung consolidation with sonographic air bronchograms. In subgroup analysis of 187 patients having lung consolidation exceeding 1 cm, ultrasonography had a sensitivity of 86% (95% CI, 71%-94%), specificity of 97% (95% CI, 93%-99%), positive LR of 28.2 (95% CI, 11.8-67.6) and negative LR of 0.1 (95% CI, 0.1-0.3) for diagnosing pneumonia.” To view another study from 2009 (!!) where they compared ultrasound to CT, go here. Or one from 2009 from the Italians (because they do everything better) go here.

Medwire from ACEP News has spread the word recently too: “Point-of-care ultrasound scanning can be used to diagnose pneumonia accurately in children and young people, show study findings. Researchers led by James Tsung, from Mount Sinai School of Medicine in New York, USA, hope that their findings could help diagnose children with pneumonia in developing countries, where deaths from the disease are particularly high. ”The World Health Organization has estimated as many as three-quarters of the world’s population, especially in the developing world, does not have access to any diagnostic imaging, such as chest X-ray, to detect pneumonia,” said Tsung in a press statement. ”Many children treated with antibiotics may only have a viral infection – not pneumonia. Portable ultrasound machines can provide a more accurate diagnosis of pneumonia than a stethoscope.” Tsung and colleagues enrolled 200 patients under the age of 21 years to take part in their study. All patients had suspected community-acquired pneumonia and all diagnoses were checked using chest radiography. The clinicians involved in the study had 1 hour of focused training in ultrasonography to diagnose pneumonia in children and young people. As reported in the Archives of Pediatric and Adolescent Medicine, the patients were aged a median of 3 years and chest radiography diagnosed pneumonia in 18% of the group. Ultrasonography, involving visualization of lung consolidation with sonographic air bronchograms, accurately diagnosed pneumonia in the majority of cases, with a sensitivity of 86%, a specificity of 89%, a positive likelihood ratio (LR) of 7.8, and a negative LR of 0.2. In patients with lung consolidation of over 1 cm, point-of-care ultrasound was even more accurate, with a sensitivity of 86%, specificity of 97%, positive LR of 28.2, and negative LR of 0.1 for diagnosing pneumonia. Kassa Darge and Aaron Chen (The Children’s Hospital of Philadelphia, Pennsylvania, USA), the authors of an accompanying editorial, say that further studies are needed to confirm these results. However, they conclude: “In the future, wherever the institutional infrastructure permits, in the diagnostic imaging algorithm for suspected pneumonia in children, ultrasonography may need to precede, augment, or even replace chest radiography.”

Oh yeah…..let the ultrasoundin’ begin!

For a very fun and funny podcast by the Ultrasound Podcast guys, go here.

For a great and complete pdf lecture on Lung ultrasound by the Critical Care Ultrasound God – aka Lichtenstein – go here.

What it can look like: look for the bright white (hyperechoic) areas within lung:

From AJR: a 2 yr old with Pneumonia – the Arrow showing pleural line; the * showing consolidation

From Ultrasound in Med and Bio:

SonoNews: Chest ultrasound for acute dyspnea used by internal medicine…yes!

In a recent publication through Medscape, they site a research article and presentation at the American College of Chest Physicians – in Chest Oct 2012  - stating “With minimal training, internal medicine house staff can successfully use hand-held ultrasound devices in the diagnosis of acute dyspnea.” This is huge! Why? Well, where do I begin? First off, lung ultrasound is advancing like never before – not that it wasn’t already known it was awesome for pneumothorax, pleural effusion, and pulmonary edema, but now the evaluation for pneumonia has gotten a lot of press. Secondly, you have more studies coming out that with minimal training, lung ultrasound can be used by physicians to help diagnose the cause for shortness of breath, which is great and helps get the fear of looking out of the conversation. FInally, and more exciting to me than anything above, is that bedside ultrasound is spreading!!! – to internal medicine (in this posting), but also to involve surgical clinics, sports medicine, pediatrics, and ophthalmologists  - – using bedside ultrasound to aid in their evaluation of their patients.

The article describes: “Ravindra Rajmane, MD, from the New York University Langone Medical Center in New York City, and colleagues reported the study findings in a poster presentation here at CHEST 2012: American College of Chest Physicians Annual Meeting. “The technology of sonography has improved markedly over the past few years,” Dr. Rajmane told Medscape Medical News. “Our study underscores the ease of transporting and effectively applying this technology with minimal training,” she said. “Our residents were able to successfully learn the basics of lung ultrasonography with a 1-hour didactic lecture followed by 1 hour of hands-on training. Unstructured training was also provided during ICU [intensive care unit] rounds.” According to the researchers, acute dyspnea is normally assessed with a combination of history taking, physical examination, electrocardiography, chest x-ray, and lab work. Lung ultrasound is increasingly being used to assess acute respiratory conditions because it is faster, less invasive, and more sensitive.” – Hallelujiah!!!

Keep it spreadin….

Even the OBGYN doctors are learning to use lung ultrasound in evaluating shortness of breath in pregnant patients!

A prior case that evaluated a patient who came in with shock and shortness of breath illustrates a way lung ultrasound can be used to help evaluate, diagnose, and work up your patient and can be find here.

SonoParty…&Journal Club… in Northern CA: Stanford, UCSF, UCSF/Fresno, UC Davis, Highland, Kaisers

Prior to leaving for ACEP in Denver, CO there was a gathering (aka “party”) at my home in sunny San Francisco with my friends and colleagues in emergency medicine / emergency ultrasound  - from all of the ultrasound programs in the region – it was amazing… and yes, wine was served! … along with pizza (of course!) We discussed 4 articles as listed below and I took down the US pearls noted from the various physicians who attended:

SonoStudy: Multicenter: The accuracy of Lung US in diagnosing community-acquired pneumonia

A recent study in the journal, Chest by ReiBig et al. that is getting quite a bit of press lately evaluates the accuracy of lung ultrasound in diagnosing community acquired pneumonia. Why this is cool? It highlights the use of lung US for pneumonia, getting closer to decreasing radiation needs for these patients (ALARA). It’s in Chest by a group of multi-disciplinary physicians (intensive care specialists, emergency medicine, radiologists). Specialists who practice in various European countries. All of that  = cool!

What they state:…

SonoApp: Lung Ultrasound… Be fine with B lines!

So you get a patient with shortness of breath, and you have no idea what the reason is…. but they can’t lie flat and the Xray tech is busy with the trauma. Lung US can help you – but that’s weird, right? Air is supposed to be the enemy of ultrasound with gas scatter artifact making what you want to see very hard. Well, believe it or not, with the lung, ultrasound will turn into your go-to tool for quick evaluation. There has been a study that has described a methodical approach to this, the RADIUS study, and one of the key elements of this is evaluating artifact. Yup, that’s right, ARTIFACT….

SonoApp: Lung Ultrasound – The down low of pneumo…with the help of Lichtenstein, of course

Lung ultrasound (aka thoracic US) is one of the currently most popular applications of bedside ultrasound. It was found to be more sensitive and specific than chest XRay for pleural effusion, pulmonary edema, and pneumothorax evaluation…. how about them apples?! There have been some recent studies suggesting that in the heat of the moment for trauma patients, the sensitivity may be slightly lower than other studies state, but it is still better than chest Xray! Not only does it take a long time to get that chest Xray done in your ED or in through your ambulatory care practice, but its more expensive than bedside limited ultrasound for the patient as well…. lets not even talk about the radiation (yes, I know, Chest Xray radiation is minimal, but it’s still radiation). The evaluation of the lungs takes no more than 3 minutes, and ultrasound machines can be found in your pocket now (should you want that kind of VERY COOL technology). US machines can also be the size of a laptop with better resolution and multiple probe capabilities – so, needless to say, its easy, portable, fast, and more accurate. Now let’s talk…