Arterial bleeding from a pelvic fracture is more common than previously thought. The doctor books used to say that 10% of bleeding was arterial and 90% was venous, so angiographic techniques were seldom used unless there was clinical evidence of blood loss. 

It looks like arterial bleeding occurs more frequently than we think. Here are tips that help you identify patients at risk:

• What type of mechanism caused the fracture? Anterior-posterior compression and vertical shear are the most common.
• Are the vital signs stable? If not, rule out the other four likely sources first (chest, abdomen, multiple extremity fractures, external). Then blame the pelvis.
• Is the fracture open? Arterial bleeding is very likely.
• How old is the patient? Elderly patients are more likely to have arterial bleeding, especially from gluteal artery branches.
• What part of the pelvis is broken? If major sacral fractures, SI joint disruption or separation of the symphysis is present, think arterial bleeding.
• Are there CT abnormalities? A vascular blush or large hematoma indicates significant bleeding.

The most common bleeding sites are the gluteal and pudendal arteries. The gluteal is in proximity to the SI joint, so this can be torn if the SI joint is damaged or the sacrum is fractured. The pudendal can be injured with ramus fractures, especially when the symphysis is widened.

If the patient can be reasonably stabilized, then a trip to interventional radiology is mandatory. Operative management is not very successful, so patients with blood pressure lability or controllable hypotension should go to IR. All active bleeding and arterial cutoffs should be embolized thoroughly.

Images: On the left is the portable plain image of a vertical shear pelvic fracture. The arrows on the right point to two areas of vascular blush.