Contrast-enhanced Ultrasound for Detection of Traumatic Splenic Bleeding in a Canine Model During Hemorrhagic Shock and Resuscitation

Background Contrast-enhanced ultrasound (CEUS) is a highly specific and sensitive method for the detection of abdominal injury. We assessed the value of CEUS for real-time monitoring of splenic trauma and detection of bleeding in a canine model of splenic injury during hemorrhagic shock and resuscitation. Methods Forty Grades III and IV traumatic splenic lesions were created in 15 mongrel dogs. Hemorrhagic shock was induced by exsanguination via the left femoral artery. Animals in shock were then resuscitated with 6% hydroxyethyl starch. CEUS was performed continuously to investigate the imaging characteristics of splenic trauma and to monitor changes in bleeding. Results Prior to induction of hemorrhagic shock, CEUS revealed active bleeding in 36 of 40 traumatic lesions (90.0%), either as contrast medium extravasation or pooling, both in the spleen and outside the capsule. During the shock period, no traumatic lesion had active bleeding. CEUS revealed that tiny branches of splenic arteries decreased in number and became thinner. The traumatic lesions appeared as nonenhanced areas with poorly defined boundaries. After fluid resuscitation, rebleeding occurred in 30 traumatic lesions, and 28 (93.3%) of these were detectable by CEUS. Conclusions CEUS allowed real-time monitoring of splenic trauma and detection of bleeding and rebleeding in hemodynamically unstable dogs, prior to and after fluid resuscitation. This suggests that CEUS might be used in clinical intensive care for patients with traumatic hemorrhagic shock.