Paper 1
Lung Ultrasound Integrated with Clinical Assessment for the Diagnosis of Acute Decompensated Heart Failure in the Emergency Department: A Randomized Controlled Trial
Pivetta, E et al. European Journal of Heart Failure, 21: 754-766. doi:10.1002/ejhf.1379
- Background information
- Acute decompensated heart failure (ADHF) is a common presentation to the Emergency Department, accounting for more than 4 million ED visits in 20161. The diagnosis can be made with a combination of history, physical examination, chest x-ray (CXR) and laboratory studies including pro-BNP. POCUS can supplement diagnosis by evaluating for pulmonary edema on lung ultrasound.
- What was the objective of this study?
- To compare the diagnostic accuracy of combining lung ultrasound and clinical assessment versus the “traditional” heart failure diagnostic work-up including clinical assessment with CXR and BNP.
- Methods and study design
- Randomized, prospective, multicenter parallel group trial
- Two centers in Italy
- Initial clinical evaluation performed including:
- History & physical
- Arterial blood gas and EKG
- Physician then was asked to decide if etiology was ADHF or non-ADHF → patients randomized to CXR and BNP group or lung US group → final “integrated” diagnosis then assigned after work-up
- Treating physicians had access to both lung US and CXR/BNP but only after their diagnosis had been assigned
- Physicians had performed at least 40 lung US exams
- Used curvilinear probe and an eight-zone protocol
- 3 or more B-lines in 2 or more zones was considered positive for interstitial fluid
- Two blinded physicians reviewed the medical records and discharge diagnosis
- Inclusion criteria:
- Age > 18 years
- Presenting to the ED with acute dyspnea or acute on chronic dyspnea in last 48 hours
- Exclusion criteria:
- Mechanically ventilated patients (invasive or non-invasive) at time of first evaluation
- Trauma
- What was the primary outcome?
- Accuracy of clinical assessment and lung ultrasound compared to clinical assessment and chest x-ray with BNP
- Secondary outcome was time needed for evaluation of assessment
- Results
- 532 total eligible patients with 518 enrolled
- 43.2% of patients had final diagnosis of ADHF
- 38.5% in CXR/BNP group and 48.1% in lung US group
- 90.7% were admitted and in-hospital mortality was 7.9%
- Sensitivity and specificity of BNP/CXR was 85% and 89.4% respectively (LR 8.0)
- Sensitivity and specificity of lung US was 93.5% and 95.5% respectively (LR 20.9)
- Median number of positive lung zones was 6 in the ADHF group versus 1 zone in the non-ADHF group
- The median time to formulate a diagnostic hypothesis was 104.5 minutes in the CXR/BNP group compared to 5 minutes in the lung US group
- Discussion
- Combining lung US with clinical evaluation outperforms the “standard” diagnostic work-up using CXR and BNP for the diagnosis of ADHF
- Adding lung US to the work-up was able to reclassify 8.9% of ADHF and 4.5% of non-ADHF patients
- Lung US significantly reduced the time to diagnosis
- Generalizability was increased by allowing patient management to be individualized to each physician
- Were there any limitations?
- Study enrolled patients with acute dyspnea so missed other presentations of ADHF
- Were not able to enroll consecutive patients due to the need for availability of lung US team
- No standard criteria was used to determine ADHF in the final diagnosis
- Not a U.S. population which may limit generalizability
- Take home points
- Lung US is a non-invasive and rapid method for evaluating interstitial fluid and can supplement the history, physical, EKG and ABG for diagnosing ADHF
- This study found eight-zone lung US to be more accurate than CXR and BNP in determining diagnosis of ADHF
- Using lung US dramatically reduced the time to final diagnosis
- Some limitations of the study are narrow inclusion criteria, non-consecutive enrollment and a non-US population which may limited generalizability
Sources
- National Hospital Ambulatory Medical Care Survey: 2011 Emergency Department Summary Tables. https://www.cdc.gov/nchs/data/ahcd/nhamcs_emergency/2011_ed_web_tables.pdf (23 November 2018).
Paper 2
Performance comparison of lung ultrasound and chest x-ray for the diagnosis of pneumonia in the ED
Bourcier, Jean-Eudes et al. The American Journal of Emergency Medicine, Volume 32, Issue 2, 115 – 118
- Background information
- Pneumonia is the number one cause of mortality from infectious disease in Western countries.
- Chest x-ray is frequently use but has poor sensitivity and specificity, especially in early disease.
- CT of the chest is considered the gold standard but comes with many downsides including ionizing radiation.
- Ultrasound has the potential to provide many benefits including speed, cost and lack of ionizing radiation.
- What was the objective of this study?
- To assess the potential of POCUS of the lung by attending emergency physicians (EPs) in diagnosing acute pneumonia
- Methods and study design
- Observational, single center study conducted in France
- Inclusion criteria:
- > 18 years of age
- Suspicion of acute pneumonia including 3 or more:
- Tympanic temperature ≥ 38oC
- Cough
- Dyspnea
- Heart rate > 100
- Oxygen saturation ≤ 92% on room air
- 10 EPs involved in the study
- Five were trained included two days of hands-on sessions with theoretical and practical training
- EPs performed 8-zone lung US using curvilinear probe on an M-Turbo machine immediately after assessment of patient
- Evaluating for bilateral alveolar-interstitial syndrome to confirm diagnosis
- All patients subsequently underwent chest x-ray → thoracic CT only if “difficult diagnosis” after x-ray
- What was the primary outcome?
- Primary outcome was diagnostic performance of lung ultrasound versus chest x-ray
- Secondary outcome was agreement between lung ultrasound and chest x-ray versus thoracic CT
- Results
- 144 total patients enrolled
- Sn/Sp for lung ultrasound was 95% and 57%
- Sn/Sp for chest x-ray was 60% and 76%
- Of 49 cases with negative CXR, final diagnosis of pneumonia was made 43 times by lung US
- Of 29 patients who underwent CT, 23 had pneumonia. Of those, ultrasound accuracy was 100%, whereas CXR was 52%
- Discussion
- Authors note significantly higher accuracy of lung US compared to CXR
- Particularly true in patients with symptoms for less than 24 hours or “difficult to diagnose” pneumonia
- Were there any limitations?
- Final diagnosis was not always made with the “gold standard” test, thoracic CT scan
- Lung ultrasound is poor at evaluating for “deep alveolar lesions” leading to likely false-negatives
- Non-US population
- Take home points
- Lung ultrasound shows promise for detection of acute pneumonia, particularly in patients with symptoms for less than 24 hours when compared to chest x-ray
- The physicians in this study were trained extensively on lung ultrasound and used an 8-zone scanning protocol which may limit generalizability
Paper 3
Emergency and Critical Care Applications for Contrast-Enhanced Ultrasound
Kummer, Tobias et al. The American Journal of Emergency Medicine, Volume 36, Issue 7, 1287 – 1294
- Background information
- There has been a 3.5-fold increase in CT imaging use for trauma patients from 1995 – 2007
- 16% of all ED patients with an injury undergo CT
- In the 1960s a cardiology named Dr. Joyner experimented with injected agitated saline during echocardiograms to enhance resolution
- This evolved into contrast enhanced ultrasound (CEUS) with original contrast material made of micro-bubbles of air within albumin/lipid shell
- How does this work?
- New commercially available contrast is made of inert gas surrounded by a lipid shell
- After injected, can be detected for 5 minutes
- Contrast bubbles are about the size of RBCs, rapidly eliminated and are not cleared renally
- Inert gas becomes exhaled and shell is metabolized in the liver
- Contrast takes advantage of acoustic impedance between blood and gas
- Approximately 1% side effect rate, mostly nausea and headache
- Risk of allergic reaction exists, at rate less than IV contrast with CT
The authors presented several studies using CEUS and their applications:
- Echocardiogram
- A 2008 prospective study found dramatic improvement in image quality when using CEUS for patients in the surgical ICU
- Noted to be a decrease in technically difficult echos from 75% to 21% after the use of CEUS
- Blunt abdominal trauma
- Studies show improvements in sensitivity and specificity for abdominal trauma with the use of CEUS compared to traditional ultrasound
- In patients with hepatic trauma, CEUS identified contrast medium extravasation at rate similar to CT with IV contrast
- Pediatric patients
- Significant increase in sensitivity and specificity with CEUS in CT-diagnosed solid organ injury over traditional ultrasound
- Almost 100% sensitivity and specificity with detection of abdominal solid injury organ with CEUS
- Use in pregnancy
- Contrast agents are classified as Category B or Category C
- Little is known about safety in breastfeeding
- More studies are needed to evaluate safety in pregnancy
- Future directions
- CEUS could be used to enhance several studies including:
- DVT/Doppler
- Distinguishing between pneumonia and other focal findings
- Active extravasation into hematoma
- Vascular compromise in ovarian torsion
- CEUS could be used to enhance several studies including:
- What are some potential limitations?
- Special ultrasound equipment and software required
- Guidelines to establish standardization of exams
- How to evaluate competency for CEUS across various training levels
- Take home points
- CEUS is a relatively new US modality which may help with improving image quality and detection of pathologies outside the scope of traditional US
- CEUS shows promise for trauma patients as contrast can detect active bleeding and solid organ injury approaching rates of CT
- More data is needed for use in pediatric and pregnant patients
- May have more use in resource limited settings where CT/trauma surgery are not readily available
