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Updated: Apr 30, 2026
Fixed Volume or Fixed Pressure: A Murine Model of Hemorrhagic Shock
Published on: June 6, 2011
When does 1:1 resuscitation really matter? An analysis of 4,858 patients from four traumatic hemorrhage studies
Thomas W Clements1, James Williams, Jeremy Cannon
1Department of Surgery, Division of Acute Care Surgery, Red Duke Trauma Institute, and The McGovern School of Medicine, University of Texas Health Science Center at Houston, Houston, Texas (T.W.C., J.W., B.A.C., J-M.V.G.); Department of Surgery, University of Pennsylvania Medical Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania (J.C.); Department of Surgery, Madigan Army Medical Center, Fort Lewis, Washington (M.S.); Department of surgery, University of Colorado Denver, Denver, Colorado (E.M.); Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida (N.N.); Department of Surgery, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (J.S.), Department of Emergency Medicine, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (F.G.).
Background:
While supported by a randomized trial and America College of Surgeon Trauma Quality Improvement Program(TQIP) guidelines, the inflection point in transfusion volumes at which balanced ratios (1:1) begin to affect mortality has not been fully explored. We sought to evaluate transfusion volumes at which a difference in mortality is observed.
Methods:
Four studies of bleeding trauma patients were analyzed: two conducted before whole blood (WB) availability; a single institution experience (Pre-WB Single Center, 2010-2016) and a randomized, multicenter trial [Pre-WB Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR), 2012-2013] and two conducted with WB use; one single institution experience (WB Single Center 2017-2021) and a prospective, multicenter study [WB Shock, Whole blood And Traumatic brain injury (SWAT), 2018-2021]. Patients were divided into balanced [1:1 or less, red blood cell (RBC):plasma] and unbalanced (>1:1) cohorts. RBC units transfused in the first four hours were evaluated (0-6, 7-10, then 10-unit intervals). Primary outcome was 30-day mortality. Secondary outcomes were four-hour and 24-hour mortality.
Results:
The Pre-WB Single Center (n = 730 1:1 or less, n = 536 >1:1) and Pre-WB PROPPR (n = 342, n = 338) noted mortality differences once >10 units of RBCs were transfused (11-20 units: 26% vs. 32%, P = 0.151 and 20% vs 30%, P = 0.090; 21-30 units: 43% vs. 71%, P = 0.013 and 32% vs. 61%, P = 0.017). The WB Single Center study (n = 1,239, n = 879) and WB SWAT (n = 447, n = 587) noted outcome separation >6 units (7-10 units: 14% vs. 22%, P = 0.139 and 14% vs. 18%, P = 0.198; 11-20: 28% vs. 41%, P = 0.118 and 17% vs. 31%, P = 0.030). Absolute differences tended to widen with greater units transfused. Differences remained at 24-hours for 7 to 10 units for Pre-WB Single Center and 11 to 20 units for Pre-WB PROPPR, WB Single Center, and WB SWAT studies.
Conclusions:
In this analysis of almost 5,000 patients, balanced resuscitation had a protective effect during or after the second transfusion cooler (>6 or >10 units of RBCs). This highlights the need for early 1:1 resuscitation with suspicion for massive hemorrhage, utilizing early WB to stay balanced and storing more immediately available plasma.
Level Of Evidence:
Retrospective comparative study without negative criteria, Study type: Therapeutic; Level III.
