Can emergency medical services personnel identify pneumothorax on focused ultrasound examinations?

Timely recognition of pneumothorax can result in prevention of the significant morbidity and mortality that is associated with respiratory compromise and hemodynamic instability in the case of tension pneumothorax. In a recent large retrospective study, de Moya [1] found a 6% incidence of pneumothorax in greater than 21,000 trauma patients. In the hospital setting, pneumothoraces are often diagnosed with X-ray and/or computed tomography (CT) scans of the thorax. The luxury of having these imaging modalities available is not afforded to those in the pre-hospital environment, where secondary and primary spontaneous pneumothoraces are missed in 39.4 and 29.4% of patients, respectively [2]. In patients who require on-the-scene airway control, an otherwise clinically insignificant pneumothorax may be converted to tension pneumothorax when positive-pressure ventilation is initiated. Conversely, there is also potential morbidity associated with pre-hospital needle decompression of those patients falsely suspected of having a collapsed lung. Internationally, physicians or allied health personnel working in underserved areas also may not always be afforded the luxury of having expensive diagnostic tools available to them. Over the past decade, ultrasound technology has drastically improved. Newer units are often smaller, lightweight, easy to use and offer outstanding imaging capabilities. The price of these ultrasound systems has also decreased. This may allow the medical team to bring “point-of-care” ultrasound to many patients who otherwise would not have advanced imaging available to them. Point-of-care ultrasound is now a rapidly growing field across the globe.

Many studies have demonstrated the utility of ultrasonography in diagnosing pneumothorax [3]. When focused diagnostic ultrasound examinations are performed on trauma patients in the hospital environment, they reduce cost and time to diagnosis [4]. Thoracic ultrasound evaluation adds mere seconds to the standard Focused Assessment with Sonography for Trauma (FAST) evaluation. Body habitus should not interfere with the ultrasound evaluation of the thorax in virtually any patient (when evaluating for pneumothorax) [5]. There are situations involving critical patients where thoracic ultrasound to evaluate for pneumothorax can be useful in the hospital, but the potential benefit of ultrasound is even greater outside of institutions where alternative diagnostic imaging modalities are not available [6].

In military operations, pre-hospital emergency medical services, or space stations where resources are limited, hand-held ultrasound as a portable imaging device has tremendous potential to aid in the timely diagnosis of various conditions. A growing body of literature has demonstrated the utility of ultrasound in such settings [7]. In recent years, there has also been a surge in bringing ultrasound technology to many countries with underdeveloped medical services, or countries with limited resources to purchase more expensive CT or MRI equipment. Furthermore, appropriate training for specific focused examinations to non-physician users may be achieved in a relatively short time period [8]. In this study, we attempt to determine whether emergency medical service (EMS) providers can be taught to identify pneumothorax on focused ultrasound examinations.