Point-of-Care Ultrasonography for Evaluation of Acute Dyspnea in the ED

What is the feasibility and diagnostic accuracy of PoCUS for the management of acute dyspnea in the ED?

• Design:

Prospective, blinded, observational study

• Population:

This study was conducted at Careggi University Hospital, a university-affiliated teaching hospital.

• Inclusion Criteria:

Patients over the age of 18 with acute dyspnea of any degree. 

• Exclusion Criteria:

Patients with dyspnea of traumatic origin, and those that were discharged from the emergency department after evaluation. 

• Intervention:

All patients were primarily assessed by 2 separate emergency physicians with vital signs, history, physical exam, and EKG.

One physician performed a Lung, Cardiac, and IVC PoCUS.

One physician performed a standard workup using any combination of Chest X-Ray, Chest CT, Echocardiogram, labs, or Arterial Blood Gas.

Both physicians were asked to make up to 2 diagnoses based on their results.

Possible diagnoses: Heart Failure, Acute Coronary Syndrome, Pneumonia, Pleural Effusion, Pericardial Effusion, COPD/asthma, Pulmonary Embolism, Pneumothorax, ARDS/ALI, Other.

• Outcomes

Primary: 

Accuracy of diagnosis:

Follow-up chart review determined the reference diagnosis. Results were compared to the diagnosis obtained from the ultrasound group and the standard workup group.

Secondary: 

Time to final diagnosis for both groups was recorded.

Time for Ultrasound completion was recorded.

3,487 total patients → 2,683 included in study

Average time to complete US: 7±2 min

Average time to Diagnosis:

Ultrasound: 24 ± 10 minutes

ED: 186 ± 72 minutes

Variable	Sensitivity - Ultrasound	Sensitivity - Standard
Heart Failure	88 (85.1-90.6)	77.3 (73.7 – 80.6)
COPD/asthma	86.6 (84.2-89.2)	92.2 (90.1-94)
Pulmonary Embolism	40 (30.1-50.6)	90.5 (82.8-95.6)

• Point-of-care ultrasound had an increased sensitivity in detecting heart failure compared to standard workup.
• Point-of-care ultrasound had a decreased sensitivity in diagnosing COPD/asthma and pulmonary embolism compared to standard workup.

There were no differences in the sensitivity or specificity of ultrasound vs. standard workup in all other diagnoses.

Strengths

Adequate sample size obtained for most diagnoses.

Gold standard diagnosis was reviewed by two separate emergency medicine physicians.

Limitations

Ultrasound sonographers focused only on those patients with dyspnea, while the treating physicians were responsible for other patients in the ED.

This likely increased the time to diagnosis for emergency physicians in the standard workup group.

Patients discharged from the hospital were not included in study.

Average age of patient population was 71, but patients 18 and over were accepted.

ARDS patient studies were underpowered.

“Integrated ultrasound methods could replace the current first diagnostic approach to patients presenting with dyspnea, allowing a drastic reduction in costs and diagnostic times.”

Point-of-Care Ultrasound in patients with dyspnea provides us with quick information to begin treatment before other laboratory and radiological tests become available. While this study showed that ultrasound was superior to the standard workup in detecting heart failure, it was slightly inferior to the standard workup in detecting COPD/asthma, and significantly inferior to standard workup in detecting pulmonary embolism. The authors speculated that with the inclusion of a DVT ultrasound study would improve the sensitivity for detecting PEs greatly.  

There have been other studies demonstrating increased sensitivity using ultrasound in patients to diagnose pneumonia and pleural effusions compared to chest x-ray. This study contributed to our knowledge of the accuracy of ultrasound in undifferentiated dyspnea by demonstrating its accuracy in these other important diagnoses. The study shows that PoCUS can guide and the emergency physician’s workup, help risk-stratify, can help us to begin treatment quickly, and improveflow and efficiency in the ED. 

This post was written by Marissa Wolfe, MS4 at Stony Brook University. Review and further commentary was provided by Amir Aminlari, MD, Ultrasound Faculty at UCSD.

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