MSS011: CONTRAST-ENHANCED FOCUSED ASSESSMENT WITH SONOGRAPHY FOR TRAUMA (CE-FAST) UTILIZATION FOR EARLY DETECTION OF NON-COMPRESSIBLE TORSO HEMORRHAGE: A SWINE MODEL
Yun Beom Lee, MD1; Michael Olson, MD1; Micaela Cuneo, MD1; Christopher Goei, MD1; Pranav Singh, MD1; Jessica Saul-McBeth, PhD1; Jason Rall2; Marlin Causey, MD, FACS1; Theodore Hart, MD, FACS1; 1Department of Vascular Surgery, Brooke Army Medical Center, Fort Sam Houston, TX, USA; 2Clinical Investigations and Research Support, 59th Medical Wing, Lackland Air Force Base, TX, USA
Objectives: Non-compressible torso hemorrhage (NCTH) remains a leading cause of preventable death in both civilian and military trauma. In environments without cross-sectional imaging modalities, the Focused Assessment with Sonography for Trauma (FAST) is used to detect hemoperitoneum, but it is limited in the evaluation of the retroperitoneum, highly user dependent, and unreliable in localizing the source of bleeding. Contrast-enhanced ultrasound (CEUS) has been reported to have a high sensitivity and specificity in assessing solid organ pathologies, but no studies have explored its use as a diagnostic tool to detect and localize NCTH.
Methods: A reproducible model of NCTH was induced in swine (35–45 kg) via laparoscopic injury to a solid organ or an endovascular injury to an aortic branch vessel. Invasive blood pressure monitoring including an intra-aortic multi-sensor pressure catheter and intravascular ultrasound (IVUS) was utilized to localize the relevant branch vessel and quantify pressure differentials across the injury site. Standard FAST exam and CEUS were performed pre and post injury in an unblinded fashion. Outcome measures include sensitivity, time to hemorrhage detection, volume of hemoperitoneum, and inter-rater reliability.
Results: CEUS was able to detect hemoperitoneum in hemodynamically stable models when standard FAST was negative. CEUS had higher specificity in hemorrhage detection showing active contrast extravasation from solid organ and vessel injuries. Contrast enhancement of solid organ parenchyma also improved free fluid detection in lower volume hemoperitoneum. The time to detection was not significantly different between injury models or use of standard FAST versus CEUS. The learning curve for the detection of NCTH was lower for CEUS over FAST alone based on inter-rater agreement scores.
Conclusion: This pilot study demonstrated the feasibility of CEUS as an alternative or adjunct to FAST for earlier detection of NCTH in multiple relevant injury patterns. Injury site was identifiable with addition of contrast. The swine model establishes a controlled and reproducible platform for the study of multiple portable technologies that may aid in hemorrhage localization in austere environments.
