Acute chest pain and dyspnea are common complaints amongst emergency department (ED) and intensive care unit (ICU) patients. These complaints account for several million annual ED visits in the United States. The list of potential diagnoses is exhaustive and critically ill patients can appear relatively well, potentially misleading the clinician. Common etiologies are of a cardiac and pulmonary nature, but also the gastrointestinal and musculoskeletal systems are frequently involved.
Physical examination and history taking are often nonspecific and clinical data such as blood pressure, heart rate, and oxygen saturation might not always reflect the true extent of the disease process. Conventional diagnostic tests such as electrocardiogram, chest x-ray, and laboratory data are initiated during the early evaluation phase, but results are not always readily available nor will they always determine the cause of illness. In this challenging situation, the physician's main goal is to distinguish cardiac from pulmonary or other causes and identify a potential life-threatening illness as quickly as possible.
Bedside ultrasound can be indispensible in evaluating patients with unexplained chest pain or dyspnea. It can add vital clinical information in a matter of minutes and is often performed simultaneously with first resuscitation efforts and other medical procedures at the patient's bedside. Ultrasound will often guide medical management and patient disposition.
Common sonographic exams utilized in such patients are pulmonary and cardiac ultrasound as well as point-of-care abdominal and vascular exam techniques. The specific sonographic exam protocols for these applications have already been discussed in previous chapters. This chapter describes an algorithm incorporating bedside ultrasound into the evaluation of ICU and ED patients presenting with acute undifferentiated chest pain or dyspnea.
Thoracic ultrasound has been shown to be highly efficient in diagnosing diseases such as pneumothorax, hemothorax, pleural effusions, pulmonary edema, pneumonia, and pulmonary embolism. In addition, other advanced applications of lung ultrasound, including acute respiratory distress syndrome (ARDS), pulmonary fibrosis, and carcinoma, although not easily diagnosed at the bedside, are currently being investigated in the critical care setting.
Physicians are familiar with the sonographic evaluation of the chest for pneumothorax and hemothorax, as this technique is part of the extended focused assessment with sonography for trauma (E-FAST) protocol. In patients with a clinical suspicion for pneumothorax, physician-performed lung ultrasound is more sensitive and specific than bedside chest x-ray when a cluster of sonographic features are evaluated, such as lung sliding, B lines, and the lung point sign. Furthermore, lung ultrasound has been found to be highly sensitive in the detection of radio-occult pneumothoraces and has been considered an alternative imaging modality to computed tomography in certain instances.
There are no clinical trials evaluating the utility of chest sonography in the diagnosis of tension pneumothorax published to date. The fact that tension pneumothorax is a clinical diagnosis and that physicians initiate needle thoracostomy immediately without reassuring imaging ...