title: Improved survival after hemostatic resuscitation: does the emperor have no clothes?
abstract: BACKGROUND
  In light of recent data, controversy surrounds the apparent 30-day survival benefit of patients achieving a fresh frozen plasma (FFP) to packed red blood cell (PRBC) ratio of at least 1:2 in the face of massive transfusions (MT) (≥10 units of PRBC within 24 hours of admission). We hypothesized that initial studies suffer from survival bias because they do not consider early deaths secondary to uncontrolled exsanguinating hemorrhage. To help resolve this controversy, we evaluated the temporal relationship between blood product administration and mortality in civilian trauma patients receiving MT.
  
  
  METHODS
  Patients requiring MT over a 22-month period were identified from the resuscitation registry of a Level I trauma center. Shock severity at admission and timing of shock-trauma admission, blood product administration, and death were determined. Patients were divided into high- and low-ratio groups (≥1:2 and<1:2 FFP:PRBC, respectively) and compared. Kaplan-Meier analysis and log-rank test was used to examine 24-hour survival.
  
  
  RESULTS
  One hundred three patients (63% blunt) were identified (66 high-ratio and 37 low-ratio). Those patients who achieved a high-ratio in 24 hours had improved survival. However, severity of shock was less in the high-group (base excess: -8.0 vs. -11.2, p=0.028; lactate: 6.3 vs. 8.4, p=0.03). Seventy-five patients received MT within 6 hours. Of these, 29 received a high-ratio in 6 hours. Again, severity of shock was less in the high-ratio group (base excess: -7.6 vs. -12.7, p=0.008; lactate: 6.7 vs. 9.4, p=0.02). For these patients, 6-hour mortality was less in the high-group (10% vs. 48%, p<0.002). After accounting for early deaths, groups were similar from 6 hours to 24 hours.
  
  
  CONCLUSIONS
  Improved survival was observed in patients receiving a higher plasma ratio over the first 24 hours. However, temporal analysis of mortality using shorter time periods revealed those who achieve early high-ratio are in less shock and less likely to die early from uncontrolled hemorrhage compared with those who never achieve a high-ratio. Thus, the proposed survival advantage of a high-ratio may be because of selection of those not likely to die in the first place; that is, patients die with a low-ratio not because of a low-ratio.
authors.affiliation: Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA. lmagnott@utmem.edu
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Magnotti
authors.forename: Ben L
authors.initials: BL
authors.lastname: Zarzaur
authors.forename: Peter E
authors.initials: PE
authors.lastname: Fischer
authors.forename: Regan F
authors.initials: RF
authors.lastname: Williams
authors.forename: Adrianne L
authors.initials: AL
authors.lastname: Myers
authors.forename: Eric H
authors.initials: EH
authors.lastname: Bradburn
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Fabian
authors.forename: Martin A
authors.initials: MA
authors.lastname: Croce
mesh_terms: D000328:Adult; D001803:Blood Transfusion / Q000379:methods* / Q000592:standards; D004906:Erythrocyte Count; D058734:Exsanguination / Q000401:mortality / Q000628:therapy; D005260:Female; D006470:Hemorrhage / Q000097:blood / Q000401:mortality / Q000628:therapy; D006487:Hemostasis / Q000502:physiology; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D010949:Plasma / Q000502:physiology; D016016:Proportional Hazards Models; D012151:Resuscitation / Q000379:methods / Q000401:mortality*; D016019:Survival Analysis; D014193:Trauma Centers / Q000706:statistics & numerical data; D014947:Wounds and Injuries / Q000401:mortality / Q000628:therapy*