Dr. McCunn prepared this summary of the changing practice with respect to massive transfusion. Several years ago, our management of intra-abdominal trauma changed from ‘definitive’ care to ‘damage control laparotomy’, which includes only source control of 1) hemorrhage and 2) gross fecal spillage. The patient undergoes abdominal or extremity wound packing, and is then taken to the ICU for warming and ongoing resuscitation. Another concept in trauma resuscitation that has emerged over the last several years is damage control resuscitation (also known as “hemostatic” resuscitation). This concept, and recent data, approximates a 1:1:1 ratio transfusion of PRBC:FFP:platelets for patients with traumatic exsanguinating hemorrhage.
After WWII it was recognized that hemorrhagic shock (HS) was optimally treated with whole blood replacement. However, in the mid-70’s, studies suggested that the optimal resuscitation of HS patients consisted of 1-2 liters of lactated ringers, accompanied by whole blood transfusion over the first 45 min after emergency department (ED) arrival. By the mid-80’s, plasma, platelets and cryoprecipitate had been removed from red cells, yet resuscitation strategies for patients in HS had not been changed to account for the new blood components. We continued to transfuse PRBC as if they were whole blood, and increasingly large amounts of crystalloid were used to maintain BP and oxygen delivery. In this situation severe coagulopathy develops, as does microvascular non-surgical bleeding and mortality from uncontrolled bleeding increases. Although commonly referred to as “DIC”, what actually occurs is minimal intravascular coagulation and the new term that has been proposed is “Acute Coagulopathy of Trauma” (ACoT).
In 2003, two independent studies described the “coagulopathy of trauma” that is present in 25% of trauma patients arriving in the ED. The triad of coagulopathy, acidosis, and hypothermia is then exacerbated and perpetuated by infusion of fluids that dilute clotting factors. Massive transfusion, traditionally described as > 10U of PRBC w/i 24 hours (and not accounting for other blood component therapy), carries a mortality rate between 20-50%, with most patients dying within 6-12 hours of hospital arrival. Damage control resuscitation addresses the lethal triad immediately on admission by using thawed human plasma as the primary resuscitation fluid in a ratio of 1:1 or 1:2 ratio with PRBC. The fibrinogen content appears to be particularly important in achieving hemostasis, and cryoprecipitate is also recommended in severe cases. As noted in the table many current component blood products are deficient in fibrinogen when compared to a unit of fresh whole blood.
Fibrinogen Content in Various Blood Products (mg)
- 1 10U bag cryoprecipitate 2,500mg in 150 mL
- 1U fresh whole blood 1,000 mg
- 1 six-pack platelets* 480mg in 300 mL (80mg per unit x 6U)
- 1U FFP 400mg in 200-250 mL
- 1U apheresis platelets 300mg in 200-250 mL
- 1U pRBCs < 100 mg
Data on fibrinogen content provided by J Hess MD, Director Blood Bank U Maryland/Shock Trauma Center and C Simon MD, Pathologist, Brooke Army Medical Center *at HUP pooled platelets are "4-pack" = 80mg x 4U = 320mg / 225mL
The recent and ongoing military experience in Iraq and Afghanistan has generated multiple studies demonstrating a decrease in mortality with a 1:1 transfusion practice. A retrospective analysis of 252 patients receiving massive transfusions (> 10 U PRBC in 24 hrs) at two U.S. Army Combat Support Hospitals (mean Injury Severity Score 21) had an overall mortality of 30%. Patients were identified as having received a low fibrinogen-to-RBC (F:R) ratio (< 0.2g) or a high F:R ratio (> 0.2 g). The mean F:R ratios transfused for the low and high groups were 0.1 g/unit and 0.48g/unit respectively (p < 0.0001). Mortality was 52% in the low and 24% in the high F:R ratio group (p< 0.001). Although other variables were associated with survival (temperature, BP, Hgb, INR, base deficit, platelet concentration, and ISS) the F:R ratio was independently associated with mortality.
Civilian guidelines for massive transfusion have typically recommended a 1:3 ratio of plasma:RBC. Records of 467 massive transfusion patients transported from the scene to 16 Level I trauma centers between July 2005-June 2006 were reviewed; survival varied from 41-74% by center. The plasma:RBC ratio ranged from 0-2.89 and the platelet:RBC ratio ranged from 0-2.5. Plasma and platelet to RBC ratios and ISS were predictors of death at 6 hours, 24 hours and 30 days. Thirty-day survival was increased in patients with high plasma: RBC and high platelet:RBC ratios. Each was associated with decreased truncal hemorrhage and increased ICU, ventilator and hospital-free days.
Borgman M et al: The ratio of blood products transfused affects mortality in patients receiving massive transfusions at a combat surgical hospital. J Trauma 2007; 63; 805-813.
Holcomb JB et al: Increased plasma and platelet to red blood cell ratios improves outcome in 466 massively transfused civilian trauma patients. Ann Surgery 2008; 3: 447-457.
Spinella PC et al: 31st Combat Support Hospital Research Working Group. Risks associated with fresh whole blood and red blood cell transfusions in a combat surgical hospital. Crit Care Med 2007; 35: 2576-2581.
Stinger HK et al: The ratio of fibrinogen to red cells transfused affects survival in casualties receiving massive transfusions at an Army combat surgical hospital. J Trauma 2008; 64: S79-85.
Wilson RF et al: Five years of experience with massive blood transfusion. JAMA 1965; 194:851-854.
Maureen McCunn, M.D., Assistant Professor of Anesthesiology and Critical Care at the Hospital of the University of Pennsylvania