Hemorrhagic Shock

Clinical features and diagnosisTop

Local symptoms of bleeding (hemorrhage) depend on its location and are not always overt. Locations include, among other sites, the gastrointestinal (GI) tract (see Gastrointestinal Bleeding) and wounds due to trauma. The sites of potential major bleeding in a hemodynamically unstable trauma patient are the long bones, chest, abdomen, retroperitoneum, and external sites. Blood pressure (BP) may not drop until 750 to 1500 mL of blood is lost. In the early stages of bleeding it is sometimes important to compare the BPs and heart rates measured in supine and standing positions. An orthostatic drop in BP ≥10 mm Hg and increase in pulse rate ≥20 beats/min suggests hypovolemia. A blood loss up to 1500 mL is usually accompanied by subtle changes in mental status, while losing half of the blood volume (2000-2500 mL) is associated with a significantly altered mental status (usually loss of consciousness). A decrease in hematocrit, hemoglobin levels, and red blood cell counts usually occurs ≥1 to 3 (4) hours after the blood loss.

TreatmentTop

1. Stop the bleeding, if possible. When necessary, refer the patient for a specialist minimally invasive surgery (eg, endoscopy in the case of GI bleeding) or radiologic assessment for embolization.

2. Continue fluid resuscitation with crystalloids (eg, ~3 mL for every 1 mL blood lost) or colloids (eg, ~1 mL for every 1 mL of blood lost) only until packed red blood cells (PRBCs) are available for transfusion (see Shock). Once blood products are available, they are the best resuscitative fluid to use in hemorrhagic shock. We suggest a target systolic BP of 80 to 90 mm Hg (mean arterial pressure, 50-60 mm Hg) until major bleeding has been stopped in the initial phase following trauma without brain injury.Evidence 1Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Low Quality of Evidence (low confidence that we know true effects of the intervention). Quality of Evidence lowered due to imprecision and inconsistency of results. Spahn DR, Bouillon B, Cerny V, et al. The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition. Crit Care. 2019 Mar 27;23(1):98. doi: 10.1186/s13054-019-2347-3. PMID: 30917843; PMCID: PMC6436241. A mean arterial pressure ≥80 mm Hg should be maintained in patients with combined hemorrhagic shock and severe traumatic brain injury (Glasgow Coma Scale ≤8 [see Table 2 in Impaired Consciousness]) in order to maintain cerebral perfusion pressures.

3. Collect blood samples for cross-matching. Request blood group typing if the group cannot be quickly and reliably established on the basis of medical records. Order and transfuse PRBCs. In patients with massive hemorrhages, do not wait for the results of the cross-matching and transfuse O Rh− blood before compatible blood arrives. If shock persists, do not allow for a hematocrit fall <30%. In patients with severe blood loss, supplement the PRBC transfusions with the administration of fresh frozen plasma (FFP) and consider platelet transfusion as well as administration of fibrinogen concentrate or cryoprecipitate (as a reasonable example, supplement transfusion of >2 units of PRBCs with 1 unit of FFP for every 2 units of PRBCs; in massive bleeding it is advised to supplement transfusions of PRBCs with FFP or fibrinogen concentrate from the beginning of treatment). Platelets should be administered based on blood counts and targeted to a level at least >50×109/L. In case of coagulopathy consider more aggressive administration of FFP, fibrinogen concentrate, cryoprecipitate, and platelet transfusions. In massive bleeding that cannot be controlled by surgical procedures, blood transfusion, or tranexamic acid (see below), consider administration of recombinant factor VIIa concentrate as rescue treatment.

4. Prevent and treat complications of massive bleeding and transfusion, including hypothermia, acidosis, and hypocalcemia (these impair blood coagulation).

5. In patients receiving anticoagulants, discontinue treatment and neutralize the effects of the drugs, if possible (see Direct Thrombin Inhibitors; see Vitamin K Antagonists).

6. In trauma patients with bleeding or at risk of significant hemorrhage, we recommend the administration of IV tranexamic acid as soon as possible and within 3 hours of injury (loading dose 1 g over 10 minutes, then 1 g over 8 hours).Evidence 2Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of intervention). Morrison JJ, Dubose JJ, Rasmussen TE, Midwinter MJ. Military Application of Tranexamic Acid in Trauma Emergency Resuscitation (MATTERs) Study. Arch Surg. 2012 Feb;147(2):113-9. doi: 10.1001/archsurg.2011.287. Epub 2011 Oct 17. PMID: 22006852. CRASH-2 trial collaborators, Shakur H, Roberts I, Bautista R, et al. Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial. Lancet. 2010 Jul 3;376(9734):23-32. doi: 10.1016/S0140-6736(10)60835-5. Epub 2010 Jun 14. PMID: 20554319.

7. Other management procedures: see Shock.

For rapid fluid resuscitation and blood transfusions, use large-bore peripheral venous catheters (preferably ≥1.8 mm [≤16 gauge]; establish 2 separate IV lines) as these allow for higher infusion rates compared with central lines. If peripheral access is not possible, a large-bore central line (such as employed for renal replacement therapy or angiography/pacing [vascular sheaths]) should be used.