Sonographic Identification of Tube Thoracostomy Study (SITTS): Confirmation of Intrathoracic Placement

INTRODUCTION Thoracostomy tubes (TT) are commonly placed in the management of surgical, emergency, and trauma patients and chest radiographs (CXR) and computed tomography (CT) are performed to confirm placement. Ultrasound (US) has not previously been used as a means to confirm intrathoracic placement of chest tubes. This study involves a novel application of US to demonstrate chest tubes passing through the pleural line, thus confirming intrathoracic placement. METHODS This was an observational proof-of-concept study using a convenience sample of patients with TTs at a tertiary-care university hospital. Bedside US was performed by the primary investigator using first the low-frequency (5-1 MHz) followed by the high-frequency (10-5 MHz) transducers, in both 2-dimensional gray-scale and M-modes in a uniform manner. The TTs were identified in transverse and longitudinal views by starting at the skin entry point and scanning to where the TT passed the pleural line, entering the intrathoracic region. All US images were reviewed by US fellowship-trained emergency physicians. CXRs and CTs were used as the standard for confirmation of TT placement. RESULTS Seventeen patients with a total of 21 TTs were enrolled. TTs were visualized entering the intrathoracic space in 100% of cases. They were subjectively best visualized with the high-frequency (10-5 MHz) linear transducer. Sixteen TTs were evaluated using M-mode. TTs produced a distinct pattern on M-mode. CONCLUSION Bedside US can visualize the TT and its entrance into the thoracic cavity and it can distinguish it from the pleural line by a characteristic M-mode pattern. This is best visualized with the high-frequency (10-5 MHz) linear transducer.