Approach to the Patient with Shortness of Breath

Introduction

Patients presenting with undifferentiated shortness of breath can be challenging because their presentations can have many potential etiologies: pulmonary, cardiac, mixed cardiopulmonary, gastrointestinal, neurologic, or other noncardiopulmonary reasons. It is important to evaluate all organ systems potentially involved using a standardized, structured fashion to reach helpful conclusions rapidly at the bedside.

Preceding chapters have explored and discussed organ-based evaluations utilizing ultrasound. This chapter will focus on integrating those applications into combined algorithmic approaches to undifferentiated shortness of breath.

Ultrasound protocols have been described for evaluation of a variety of symptoms and diagnostic concerns. Perhaps the most well-known is the focused assessment with sonography for trauma (FAST) examination looking for free fluid in the setting of trauma, which was expanded to the eFAST examination to assess for traumatic pneumothorax. Other well-known protocols that include assessments for dyspnea include the focused assessment with sonography for HIV-associated tuberculosis (FASH) and the rapid ultrasound in shock (RUSH) examination for hypotension.

Examples of specific algorithms for the ultrasound evaluation of undifferentiated dyspnea include the bedside lung ultrasound in emergency (BLUE) protocol and the rapid assessment of dyspnea with ultrasound (RADiUS) protocol. The BLUE protocol evaluates the lungs only and is useful for the diagnosis of pneumothorax, pulmonary edema, pulmonary consolidation, and pleural effusions. The RADiUS protocol includes echocardiographic and inferior vena cava (IVC) evaluation, in addition to the pulmonary examination. A fluid administration limited by lung sonography (FALLS) protocol combines cardiac and lung views to sequentially rule out obstructive and cardiogenic shock while expediting diagnosis of distributive (usually septic) shock and monitoring for development of pulmonary edema as a result of fluid resuscitation.

Most algorithms combine the cardiac examination (including the IVC) with a thoracic examination, culminating in a “focused chest” assessment, as many life-threatening etiologies of dyspnea have cardiopulmonary origins. This approach is similar to the methods for evaluation of undifferentiated chest pain and hypotension described in other chapters.

Technique

The sequence for obtaining views varies, depending on the pretest probability of certain diagnoses obtained from the history and physical examination. Many sonologists choose to start with echocardiographic views, as the heart is essential.