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Unstable Pelvic Fracture With Negative FAST: Hemorrhage Control [ Case Discussion ](https://mdster.com/blog?category=case-discussion) Unstable Pelvic Fracture With Negative FAST: Hemorrhage Control ================================================================= Physiologic reasoning and definitive management when profound traumatic shock outpaces bedside imaging [ MDster Editorial Team ](https://mdster.com/about) · Aug 11, 2026 · 5 min read · 39 [ Reviewed by Dr. Ali Ragab, MBBCH, MSc, MCAI ](https://mdster.com/medical-reviewers/dr-ali-ragab) [Editorial Policy](https://mdster.com/editorial-policy) | [Corrections Policy](https://mdster.com/corrections) [ Emergency Medicine ](https://mdster.com/blog?tag=emergency-medicine) [ Pelvic Trauma ](https://mdster.com/blog?tag=pelvic-trauma) [ Hemorrhagic Shock ](https://mdster.com/blog?tag=hemorrhagic-shock) [ FAST Examination ](https://mdster.com/blog?tag=fast-examination) [ Damage-Control Resuscitation ](https://mdster.com/blog?tag=damage-control-resuscitation) [ Angioembolization ](https://mdster.com/blog?tag=angioembolization) ![Unstable Pelvic Fracture With Negative FAST: Hemorrhage Control](https://mdster.com/storage/blog/images/unstable-pelvic-fracture-with-negative-fast-hemorrhage-control.jpg) Share this article Share this post On this page 1. [ Localizing the Hemorrhage ](#localizing-the-hemorrhage) 2. [ Why a Negative FAST Is Not Reassuring ](#why-a-negative-fast-is-not-reassuring) 3. [ Immediate Damage-Control Priorities ](#immediate-damage-control-priorities) 4. [ Stabilize the pelvic ring ](#stabilize-the-pelvic-ring) 5. [ Resuscitate hemostatically ](#resuscitate-hemostatically) 6. [ Choosing Definitive Hemorrhage Control ](#choosing-definitive-hemorrhage-control) 7. [ The laparotomy trap ](#the-laparotomy-trap) 8. [ When CT Becomes Appropriate ](#when-ct-becomes-appropriate) 9. [ Hypothermia During Hemorrhage Control ](#hypothermia-during-hemorrhage-control) 10. [ Clinical Application ](#clinical-application) 11. [ Key Points for Board Exams ](#key-points-for-board-exams) 12. [ Conclusion ](#conclusion) 13. [ Frequently Asked Questions ](#blog-faqs) 14. [ References ](#references-heading) On this page 1. [ Localizing the Hemorrhage ](#localizing-the-hemorrhage) 2. [ Why a Negative FAST Is Not Reassuring ](#why-a-negative-fast-is-not-reassuring) 3. [ Immediate Damage-Control Priorities ](#immediate-damage-control-priorities) 4. [ Stabilize the pelvic ring ](#stabilize-the-pelvic-ring) 5. [ Resuscitate hemostatically ](#resuscitate-hemostatically) 6. [ Choosing Definitive Hemorrhage Control ](#choosing-definitive-hemorrhage-control) 7. [ The laparotomy trap ](#the-laparotomy-trap) 8. [ When CT Becomes Appropriate ](#when-ct-becomes-appropriate) 9. [ Hypothermia During Hemorrhage Control ](#hypothermia-during-hemorrhage-control) 10. [ Clinical Application ](#clinical-application) 11. [ Key Points for Board Exams ](#key-points-for-board-exams) 12. [ Conclusion ](#conclusion) 13. [ Frequently Asked Questions ](#blog-faqs) 14. [ References ](#references-heading) A 32-year-old motorcyclist arrives with an unstable pelvic ring, perineal ecchymosis, HR 135 bpm, and BP 75/40 mmHg. FAST shows no intraperitoneal fluid, yet transfusion fails to restore perfusion. The immediate threat is presumed pelvic hemorrhage, but the negative ultrasound must not produce diagnostic closure. Localizing the Hemorrhage ------------------------- The most likely source is a **retroperitoneal pelvic hematoma**. Mechanically unstable fractures disrupt cancellous bone, the presacral and pelvic venous plexuses, and occasionally branches of the internal iliac arterial system. Venous and bony bleeding predominates, while arterial injury becomes increasingly important when shock persists despite reduction and transfusion. The retroperitoneum can accommodate substantial blood without producing intraperitoneal free fluid. Alternative sources still require rapid exclusion: - Occult hemothorax or other thoracic hemorrhage - Intraperitoneal solid-organ or mesenteric injury - Long-bone, junctional, or external bleeding - Obstructive shock from tension pneumothorax or tamponade - Neurogenic shock, although this physiology is less consistent with marked tachycardia and vasoconstriction Perineal and scrotal bruising also raises concern for urethral, bladder, rectal, genital, or open pelvic injury. These injuries require examination and targeted investigation, but hemorrhage control takes priority. Why a Negative FAST Is Not Reassuring ------------------------------------- FAST evaluates dependent intraperitoneal spaces; it does not visualize retroperitoneal pelvic bleeding. Furthermore, FAST sensitivity for hemoperitoneum is reduced in major pelvic trauma. A negative result therefore neither proves that bleeding is exclusively pelvic nor safely excludes abdominal injury. [\[1\]](#cite-1 "Reference [1]") Repeat FAST may identify evolving hemoperitoneum, but serial scanning must not delay hemorrhage control. CT is appropriate only after the patient becomes sufficiently stable for transport and imaging. > **Clinical Pearl:** In an unstable trauma patient, FAST is a decision aid—not a clearance test. Negative FAST plus an unstable pelvis should trigger pelvic hemorrhage control while the team continues searching for competing sources. Immediate Damage-Control Priorities ----------------------------------- ### Stabilize the pelvic ring Apply a purpose-designed binder or tightly secured sheet centered over the **greater trochanters**, not the iliac crests. This reduces displacement and pelvic volume while supporting clot formation. Avoid repeated pelvic compression examinations. Once instability is suspected, further manipulation can disrupt early thrombus formation. ### Resuscitate hemostatically Activate the institutional massive transfusion protocol and prioritize whole blood, where established, or balanced component therapy. Many protocols begin near a 1:1:1 RBC-to-plasma-to-platelet strategy, then transition according to conventional or viscoelastic testing. Additional priorities include: - Minimize crystalloid administration - Administer TXA when indicated within the accepted early trauma window - Monitor and replace ionized calcium - Warm the patient, environment, fluids, and blood products - Follow lactate, base deficit, fibrinogen, platelet count, and coagulation studies Current trauma guidance emphasizes early pelvic stabilization, blood-based resuscitation, and immediate progression toward hemorrhage control in persistent shock. [\[2\]](#cite-2 "Reference [2]") Choosing Definitive Hemorrhage Control -------------------------------------- A patient with SBP 70 mmHg despite a binder and transfusion should not be sent to CT. The next destination is the location capable of delivering the fastest effective intervention. Clinical pathwayPreferred responsePositive FAST with persistent shockLaparotomy plus coordinated pelvic stabilization or packingNegative FAST with immediate IR accessAngiography and embolizationNegative FAST with delayed or unavailable IRExternal fixation and preperitoneal pelvic packingPatient in extremisConsider zone 3 REBOA as a bridge in an experienced system Angioembolization treats arterial hemorrhage but does not directly control diffuse venous or cancellous bleeding. Preperitoneal pelvic packing compresses those low-pressure sources and is particularly valuable when angiography cannot be delivered rapidly. Consequently, angiography versus packing is not a universal either-or question. Current consensus supports an institutional algorithm based on physiology, associated injuries, and immediate resources; some patients require both. [\[2\]](#cite-2 "Reference [2]") ### The laparotomy trap Laparotomy is appropriate when intraperitoneal hemorrhage is identified or strongly suspected. The danger is a nontherapeutic laparotomy or inadvertent entry into the preperitoneal hematoma, which releases tamponade and may accelerate bleeding. If laparotomy is required, the pelvic hematoma should not be opened. Preperitoneal packing uses a separate extraperitoneal approach when pelvic control is needed. [\[2\]](#cite-2 "Reference [2]") When CT Becomes Appropriate --------------------------- If resuscitation produces durable stability, contrast-enhanced CT can define associated injuries and guide intervention. Pelvic arterial contrast extravasation is the strongest imaging indication for angioembolization, although its absence does not exclude arterial injury. Gross hematuria warrants bladder imaging, while suspected urethral injury requires urethral evaluation before repeated catheter attempts. These investigations must follow, not precede, control of ongoing exsanguination. Hypothermia During Hemorrhage Control ------------------------------------- A temperature of 34.5°C worsens trauma-induced coagulopathy through impaired platelet function and reduced coagulation-enzyme activity. Routine laboratory testing performed after warming specimens may underestimate the patient’s in-vivo dysfunction. Active warming is therefore a hemostatic intervention, not supportive housekeeping. Failure to correct hypothermia promotes continued oozing despite technically successful packing or embolization. [\[3\]](#cite-3 "Reference [3]") Clinical Application -------------------- An appropriate response to a request for pre-angiography CT would be: “The patient remains in refractory hemorrhagic shock and is unsafe for CT transport. We need immediate pelvic hemorrhage control according to our institutional pathway—angiography now if available without delay, or operative stabilization and preperitoneal packing.” Key Points for Board Exams -------------------------- - FAST does not detect retroperitoneal pelvic hemorrhage. - Negative FAST cannot reliably exclude hemoperitoneum in major pelvic injury. - Place the binder over the greater trochanters. - Persistent shock requires hemorrhage control, not CT localization. - Angioembolization targets arterial bleeding; packing targets venous and bony bleeding. - Avoid opening a contained pelvic hematoma during laparotomy. - Hypothermia directly impairs clot formation. Conclusion ---------- In unstable pelvic trauma, physiology outranks imaging. Rapid stabilization, hemostatic resuscitation, and the fastest available route to definitive hemorrhage control offer the best chance of interrupting exsanguination. Frequently Asked Questions ---------------------------- ### Can a negative FAST exclude abdominal bleeding in pelvic trauma? No. FAST does not assess the retroperitoneum and has inadequate sensitivity to exclude hemoperitoneum in major pelvic injury. ### Should an unstable patient undergo CT before pelvic angioembolization? No. Persistent shock despite resuscitation makes CT transport unsafe. Proceed to the fastest available definitive hemorrhage-control pathway. ### Where should a pelvic binder be positioned? Center it over the greater trochanters. Placement over the iliac crests provides inadequate pelvic-ring reduction. ### Is angioembolization always preferred over pelvic packing? No. Angioembolization controls arterial bleeding, whereas preperitoneal packing addresses venous and bony bleeding. Choice depends on physiology, associated injuries, and local availability. ### Why is hypothermia dangerous during pelvic hemorrhage? It impairs platelet function and coagulation-enzyme activity, worsening coagulopathy and ongoing blood loss. References (4) ------------------ 1. 1. [ Eastern Association for the Surgery of Trauma. Pelvic Fracture Hemorrhage—Update and Systematic Review. ](https://www.east.org/education-resources/practice-management-guidelines/details/pelvic-fracture-hemorrhageupdate-and-systematic-review-update-in-process) [↩](#cite-ref-1-1 "Back to text") 2. 2. [ Joint Trauma System. Pelvic Fracture Care Clinical Practice Guideline. February 17, 2026. ](https://jts.health.mil/assets/docs/cpgs/Pelvic_Fracture_Care_17_Feb_2026_ID34v1.1.pdf) [↩](#cite-ref-2-1 "Back to text") 3. 3. [ Rossaint R, et al. European guideline on management of major bleeding and coagulopathy following trauma: sixth edition. Critical Care. 2023. ](https://pmc.ncbi.nlm.nih.gov/articles/PMC9977110/) [↩](#cite-ref-3-1 "Back to text") 4. 4. [ Coccolini F, et al. Pelvic trauma: WSES classification and guidelines. 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