Lung PoCUS – Podcast

Posted on May 31, 2020 by David Lewis

Lung PoCUS in Pediatric Emergency Medicine – Podcast

PoCUS Fellowship Clinical Pearl (RCP) May 2020

Dr. Mandy Peach (Emergency Physician and Dalhousie PoCUS Fellow, Saint John, NB, Canada)

Extract:

“My name is Mandy Peach and I am Emergency Physician at the Saint John Regional Hospital in Saint John, New Brunswick. I’m currently completing a PoCUS Fellowship and a pediatric rotation through the IWK Emergency Department in Halifax…….

What is the evidence for the use of PoCUS and diagnosing pediatric pneumonia. Well trained PoCUS Physicians can identify pneumonia with a sensitivity of 89% and a specificity of 94%, compared community-acquired pneumonia chest x-ray has a sensitivity of 69% and a specificity of 100%, if you see it great…. but what about early bacterial pneumonia and this case PoCUS has the upper hand, and if you consider consolidations behind the heart that can be visualized on PoCUS and obscured on chest x-ray – PoCUS 2 chest x-ray zero. So clearly it’s a useful tool to have when trying to differentiate between bacterial pneumonia that requires treatment and viral causes that would indicate conservative management. So how do we actually ultrasound the lungs…..the first step is to make the kid comfortable scan them in a position of comfort for example and their parents arms what the patient touch the ultrasound gel or the probe so it’s less of a scary thing maybe play their favourite music or YouTube video on the background or give them their favourite or snack do you want to choose a high frequency linear probe and scanning the longitudinal plane ……….”

Listen to the Podcast for some useful tips on performing and interpreting lung ultrasound in the pediatric population.

Deep Dive Lung PoCUS – COVID 19 Pandemic

Posted on May 7, 2020 by David Lewis

SJRHEM Weekly COVID-19 Rounds – May 2020

Dr. David Lewis

Part One covers aspects of core and advanced aspects of lung ultrasound application including: Zones, Technique, and Artifacts

Part Two covers PoCUS in COVID, the recent research, PoCUS findings, Infection Protection and Control, Indications and Pathways.

Part 1

Part 2

Whose Line is it Anyway? – PoCUS in a Patient with Dyspnea

Posted on April 30, 2020 by David Lewis

Medical Student Clinical Pearl – March 2020

Nguyet (Na) Nguyen

MD Class of 2021

Memorial University of Newfoundland

Reviewed and Edited by Dr. David Lewis

All case histories are illustrative and not based on any individual

Case Report

ID: 60 y/o M with dyspnea presenting to the ED late evening

HPI: Patient complained of increasing SOB starting the morning on day of presentation, with a worsening 3 days of non-productive cough. No chest pain or other cardiac features. No complaint suggestive of URTI or GI illness. Patient was given Atrovent and Ventolin en route by EMS, and was allegedly moving more air into his lungs after this intervention. Patient reports no ankle swelling, paroxysmal nocturnal dyspnea, but reports using 2 pillows to elevate himself when sleeping. Patient reports no fever, unexplained weight loss or fatigue.

Past medical history includes chronic back pain, DM, atrial fibrillation, peripheral DM-related ulcers, chronic kidney disease, BPH, colon cancer with hepatic metastases. Past surgical history significant for 5x CABG, liver and colon resection.

His medications are amitriptyline 10mg PO qhs, acetaminophen 650mg PO BID, dutasteride 0.5mg PO daily, ferrous sulfate 300mg PO daily, furosemide 40mg PO BID, metformin 500mg BID, pantoprazole 40mg PO BID, pregabalin 150mg PO BID, primidone 125mg PO daily, rosuvastatin 40mg PO qhs, rivaroxaban 15mg PO daily.

He has a distant 10 pack-years smoking history, drinks alcohol occasionally, and does not use recreational drugs. The patient lives with his wife in their own home.

Physical exam: Patient was markedly pale, non-diaphoretic, in tripod position with increased work of breathing. His temperature was 36.9, regular pulse rate at 105, respiratory rate 22, oxygen saturation 90% on room air and a nebulizer mask through which he was receiving aerosolized Atrovent and Ventolin. His BP was 125/78mmHg.

Cardiovascular exam revealed distant S1S2 in a chest with no visible deformity. His JVD was at the level of the sternal angle, there was no pedal edema bilateral. Capillary refill was 3 seconds bilateral at the thumbs. Percussion revealed no focal dullness, however on auscultation, basal crackles were heard more prominently in the right lung base, though also present on the left. There were also wheezes noted in the upper lobes heard in the anterior chest. Abdomen was soft, non-distended, non-tender. Neurological exam unremarkable.

Investigations: ECG showed sinus tachycardia with a LBBB, bloods drawn for routine labs, VBG, lactate, CXR ordered.

Differential diagnosis: AECOPD vs congestive heart failure.

PoCUS (Arrival Time + 10 mins): B-lines were observed in both lungs when a curvilinear probe was placed over different areas of the anterior chest. A small pleural effusion was also noted at the bottom of the right lung. B-lines represent increased fluid in an area of the lung, and given different clinical contexts maye represent pulmonary edema, pneumonia, or pulmonary contusion. In this case the most likely explanation for bilateral diffuse B-Lines is CHF and Pulmonary Edema.

Working Diagnosis (Arrival Time + 10 mins): CHF and Pulmonary Edema

Management (Arrival Time + 15 mins): Pending transfer fo CXR and results of investigations the patient was treated with intravenous diuretics. He passed 500mls of urine and his symptoms improved considerably.

Investigations Results (Arrival Time + 45 mins): leukocytes 6.4, hemoglobin 83, platelet 165, sodium 140, potassium 5/0, chloride 101, creatinine 120, urea 11.7, glucose 17.0. Venous blood gas showed pH 7.31, pCO2 555, HCO3- 28 and lactate 2.7.

CXR (Arrival Time + 45 mins):

CXR was similar to above, this image is from: https://radiopaedia.org/cases/acute-pulmonary-oedema-6

Final impression: Congestive heart failure

What are B Lines?

These are the ultrasound equivalent of Kerley-B lines often reported on chest X-ray, which indicate edema in the lungs. For an exam to be positive (i.e indicative of pathology), one needs to see a minimum of 3 B-lines per view. B-lines look like flashlight beams traveling undisrupted down the entire ultrasound screen, as seen in the images above obtained during the exam.

These need to be distinguished from other artifacts such as ‘A-lines’ and ‘comet tails’. A-lines are seen in normal lungs. These are ‘repetitive reverberation’ artifacts of the normal pleura in motion. (Figure 1)(1)

‘Comet tails’- reported first by Lichenstein et al. in 1998 (although he was describing B-Lines in this paper) (Figure 2) (1), are ‘short, hypoechoic artifacts’ that only descend vertically partially down the screen. These are normal lung artifacts. This paper explains “a common misunderstanding in lung ultrasound” nomenclature that stems from Lichtenstein’s original paper.

Download pdf

From: https://www.mdedge.com/emergencymedicine/article/96697/imaging/emergency- ultrasound-lung-assessment

More on Comet Tails Artifact in this post from LitFL:

Comet tail artefact

Protocols

There are multiple protocols that guide the ultrasound technique (4) , some of which are:

Lichenstein et al (1998): longitudinal scans of anterior and lateral chest walls of patients in semi- recumbent position. Positive test defined as bilateral multiple B-lines diffuse anterolateral or lateral. The protocol had reported sensitivity (true positive) of 100%, and specificity (true negative) 92% for cardiogenic pulmonary edema. Blue Protocol (2015)
Liteplo et al (2008): anterior and lateral chest walls with patient supine: each chest divided into 4 zones (anterior, lateral, upper and lower). Positive test: pathologic pattern found in >1 zone on each side, with both sides involved.
Volpicelli et al. (2008): longitudinal scans of supine patients with chest divided into 11 areas (3 anterior R, 3 lateral R, 2 anterior L, 3 lateral L) to obtain score 0-11. Scores strongly correlated with radiologic and BNP (lab marker of CHF) at presentation.

What is the Evidence?

Al Deeb et al. conducted a systematic review and analysis of prospective cohort and prospective case-control studies in the ED, IDU, inpatient wards and prehospital settings (n = 1075). This was published in Acad Emerg Med (2014), which reported a sensitivity of 94.1% for using B-lines to diagnosis acute cardiogenic pulmonary edema (ACPE), and a specificity of 92.4% for patients with a moderate- high pretest probability for ACPE.

The SIMEU Multicenter study reported in 2015 reported a significantly higher accuracy (97% sensitivity and 97.4% specificity) with an approach incorporating lung ultrasound (LUS) in differentiating acute decompensated heart failure (ADHF) and non-cardiac causes of acute dyspnea, compared to approaches using the initial clinical workup (past medical history, history of presenting illness, physical examination, ECG, ABG), chest X-ray alone and natriuretic peptides.

Martindale et al. reported in 2016 (Academic Emergency Medicine) high positive likelihood ratio of pulmonary edema observed on lung ultrasound and low negative likelihood ratio of B-line pattern on lung US in affirming the presence of acute heart failure, after a systematic review and analysis of 57 prospective and cross-sectional studies (n = 1,918).

A useful Systematic Review “Emergency department ultrasound for the detection of B-lines in the early diagnosis of acute decompensated heart failure: a systematic review and meta-analysis ” from McGivery et al from SJRHEM (7), was published in 2018.

Learning Point

For a patient presenting to the ER with dyspnea, using PoCUS to observe 3 or more B-lines in two bilateral lung zones +/- pleural effusion can rapidly guide an accurate diagnosis of acute congestive heart failure.

References

Taylor, T., Meer, J., Beck, S. Emerg Med. (2015) https://www.mdedge.com/emergencymedicine/article/96697/imaging/emergency- ultrasound-lung-assessment Last accessed Feb 29, 2020
Lee, FCY, Jenssen, C., Dietrich, CF Med Ultrason (2018); 20(3): 379-384
Ang SH. & Andrus P Curr Cardiol Rev. 2012 May; 8(2): 123-136https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3406272/
Al. Deeb M., Barbic S., Featherstone R., Dankoff J., Barbic D. Acad Emerg Med 2014 Aug; 21(8): 843-52 https://www.ncbi.nlm.nih.gov/pubmed/25176151
Pivetta E et al. Chest. 2015 Jul; 148(1): 202-210 https://www.ncbi.nlm.nih.gov/m/pubmed/25654562/
Martindale JL, Wakai A, Collins SP, Levy PD, Diercks D, Hiestand BC, Fermann GJ, deSouza I, Sinert R, Acad Emerg Med. 2016 Mar; 23(3): 223-242 https://www.ncbi.nlm.nih.gov/pubmed/26910112
McGivery K, Atkinson P, Lewis D, et al. Emergency department ultrasound for the detection of B-lines in the early diagnosis of acute decompensated heart failure: a systematic review and meta-analysis. CJEM. 2018;20(3):343‐352. doi:10.1017/cem.2018.27

Lung Ultrasound in the Evaluation of Pleural Infection

Posted on July 31, 2019 by David Lewis

Lung Ultrasound in the Evaluation of Pleural Infection

Resident Clinical Pearl (RCP) July 2019

Yazan Ghanem – PGY5 Internal Medicine, Dalhousie University

SJRHEM PoCUS Elective

Reviewed and edited by Dr. David Lewis.

CASE: MR. WHITE

83 year old male with known past medical history of mild cognitive impairment (lives alone in assisted living). Two weeks prior to current presentation, he was admitted with community acquired pneumonia and discharged after 2 nights of hospital stay on oral antibiotics.

He is now presenting with 5 days history of worsening dyspnea, fever, fatigue and reduced oral intake. Vital signs are: Temperature 38.4 C; heart rate 80/min; Blood pressure 121/67; Respiratory rate 28/ minute; Oxygen saturation 90% on room air. His chest exam showed reduced air entry and dullness to percussion in the right hemithorax.

CXR:

Bedside POCUS:

Pleural fluid analysis:

• WBC – 22,000 cells per uL

• LDH – 1256 Units / L

• Glc – 2.2 mmol / L

• pH – 7.18

• Gram Stain – Neg

Next steps in management?

A – 14 Fr pleural drain + Start IV Levofloxacin

B – 28 Fr pleural drain + Start Ceftriaxone / Azithromycin

C – 14 Fr pleural drain + Start Piperacillin – Tazobactam

D – Start Ceftriaxone / Azithromycin + Repeat CXR in 1 week

(See end of page for answer )

Normal Thoracic Ultrasound:

Thoracic Ultrasound is limited by bony structures (ribs and scapulae) as well as by air within lungs (poor conductor of sound waves).

With the transducer held in the longitudinal plane:

1 – Ribs are visualized as repeating curvilinear structures with a posterior acoustic shadow.

2 – Overlying muscle and fascia are seen as linear shadows with soft tissue with soft tissue echogenicity.

3 – Parietal and visceral pleura is visualized as a single echogenic line no more than 2 mm in width which “slides” or “glides” beneath the ribs with respiration. Two separate lines can be seen with a high frequency transducer.

4 – Normal aerated lung blocks progression of sound waves and is characterized by haphazard snowstorm appearance caused by reverberation artifact.

5 – Diaphragms are bright curvilinear structures which move with respiration. Liver and spleen have a characteristic appearance below the right and left hemi diaphragms respectively.

Pleural Effusion:

Ultrasound has higher sensitivity in detecting pleural effusions than clinical examination and chest X-Ray.

On Ultrasound, pleural effusions appear as an anechoic or hypoechoic area between the visceral and parietal pleura that changes in shape with respiration. Atelectatic lung tissue appear in the far field as flapping or swaying “tongue-like” echodensities.

Ultrasound morphology:

1- Anechoic Effusion: Totally echo-free (Could be transudative or exudative)

2- Complex Non-septated: Echogenic appearing densities present (fibrinous debris). Always exudative.

3- Complex Septated: Septa appear in fluid. Always exudative.

Parapneumonic Effusions and Empyema:

Ultrasound is superior to CT in demonstrating septae in the pleural space. However, CT is recommended for evaluation of complex pleuro-parenchymal disease and loculated pleural collections if drainage is planned: There is no correlation between ultrasound appearance and the presence of pus or need for surgical drainage; however, the presence of a septated appearing parapneumonic effusion correlate with poorer outcomes (longer hospital stay, longer chest tube drainage, higher likelihood for need for fibrinolytic therapy and surgical intervention.

Parapneumonic effusions appear as hyperechoic (with or without septae) on ultrasound.

Pulmonary Consolidation:

Pulmonary consolidation is sonographically visible in the presence of a pleural effusion that acts as an acoustic window or if directly abutting the pleura.

It appears as a wedge-shaped irregular echogenic area with air or fluid bronchograms.

Back to Mr. White

Next steps in management?

A – 14 Fr pleural drain + Start IV Levofloxacin

B – 28 Fr pleural drain + Start Ceftriaxone / Azithromycin

C –14 Fr pleural drain + Start Pipercillin- Tazobactam

D – Start Ceftriaxone / Azithromycin + Repeat CXR in 1 week

Rationale:

Complicated parapneumonic effusions should be managed with drainage and antibiotics that will treat anaerobic infection. An alternative would be a combination of Ceftriaxone and Metronidazole (No pseudomonas coverage). Levofloxacin alone does not add any anaerobic coverage. Azithromycin has poor penetration into loculated pleural collections.

References

British Thoracic Society – Pleural Disease Guideline – 2010

https://thorax.bmj.com/content/65/8/667

PoCUS – Pleural Effusion

Posted on March 2, 2019 by David Lewis

Medical Student Clinical Pearl

James Kiberd

Class 2019 Dalhousie Medicine

Reviewed and Edited by Dr. David Lewis

Case:

A 90 year-old male presented with worsening shortness of breath on exertion, crackles bilaterally at the bases on auscultation with known history of congestive heart failure. Bedside ultrasound was performed to assess for pleural effusion

Lung Views:

In order to perform ultrasound of the lungs, there are four views that are obtained (see Figure 1). Place the patient supine. The high frequency linear array transducer is often used, but either the phased array or curvilinear transducers can be used. The first views are taken at both right and left mid-clavicular lines of the anterior chest. With the marker of the transducer pointed toward the patient’s head, a minimum of 3-4 rib spaces should be identified. The next views are of the posterior-lateral chest. The patient can be supine or in the sitting position. It is these views where a pleural effusion can be identified.

Figure 1: Chest views with ultrasound. ‘A’ are anterior chest view positions and ‘B’ are posterolateral view positions

Pleural Effusion

Pleural effusion is assessed by ultrasound placing the transducer in the midaxillary line with the marker oriented toward the patient’s head. On the patient’s right side the diaphragm, the liver, and the vertebral line can be seen. On the left, the diaphragm, spleen, and vertebral line should be in view. In a patient without pleural effusion, one should not be able to visualize the lung as it is mostly air and scatters the sound produced by the transducer. However, in the presence of pleural effusion, the area above the diaphragm is filled with fluid and therefore will appear anechoic. In addition, the vertebral line will be present past the diaphragm as the fluid allows the sound waves to propagate and not scatter. This is known as the ‘spine sign’ (also known as the ‘V-line’). Finally, one is often able to see the atelectatic lung float and move with respirations in the fluid, this is known as the ‘sinusoid sign.’ These are the three criteria outlined by consensus statements in the identification of pleural effusions.¹ Occasionally, the area above the diaphragm may look like spleen or liver, but this is known as ‘mirror image’ artifact and is normal.² Figure 2 shows both the right and left views of our patient.

Figure 2: Pleural effusion showing anechoic pleural fluid, atelectatic lung, and ‘spine sign

Accuracy with Ultrasound

Ultrasound is more accurate than either chest x-ray or physical exam in the identification of small pleural effusions.³ For a chest x-ray to identify fluid there usually needs to be more than 200cc present.² A meta-analysis found that ultrasound had a mean sensitivity of 93% (95%CI: 89-96%) and specificity of 96% (95%CI: 95-98%).⁴

Our patient went on to have a chest x-ray where he was found to have bilateral pleural effusions (see Figure 3).

Figure 3: Bilateral pleural effusions seen on chest radiography in our patient.

In Summary

Three criteria are used to identify pleural effusion on ultrasound; anechoic fluid above the diaphragm, the ability to visualize the spine above the diaphragm (‘spine sign’), and atelectatic lung moving with respirations (‘sinusoid sign’). Lung ultrasound for the detection of pleural effusion is more reliable to identify small effusions in comparison to both radiography and physical exam.

References:

Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591. doi:10.1007/s00134-012-2513-4.
Liu RB, Donroe JH, McNamara RL, Forman HP, Moore CL. The practice and implications of finding fluid during point-of-care ultrasonography: A review. JAMA Intern Med. 2017;177(12):1818-1825. doi:10.1001/jamainternmed.2017.5048.
Wong CL, Holroyd-leduc J, Straus SE. CLINICIAN ’ S CORNER Does This Patient Have a Pleural Effusion ? PATIENT SCENARIO. Jama. 2010;301(3):309-317. doi:10.1001/jama.2008.937.
Grimberg AI, Carlos Shigueoka DI, Nagib Atallah III Á, et al. Diagnostic accuracy of sonography for pleural effusion: systematic review Acurácia diagnóstica da ultrassonografia nos derrames pleurais: revisão sistemática