Pre-hospital fibrinogen levels in major trauma
patients transported by helicopter emergency
medical service: Determining who might
benefit
Shannon Pretty, Domhnall O’Dochartaigh, Elfriede
Cross, Efrem Violato, Julie Zwicker, A. Gauri, P. Chen,
X. Cravetchi, Sandy Widder, Parker Arabesque, L. Solis
Aguilar, Matthew Douma, Christopher Picard, and Eddie
Chang
Background: Low fibrinogen contributes to poor outcomes
in patients with traumatic coagulopathy. Upon Emergency
Department (ED) arrival, some major trauma patients are coagulopathic, and have low fibrinogen levels, though who, is not clear.
In helicopter transported trauma patients, who are transfused
blood during transport, we seek to identify prehospital clinical
variables that are associated with ED hypofibrinogenemia.
Methods: We conducted a health records review of consecutive helicopter Emergency Medical Services (EMS) transported
patients to two trauma centers who received one or more units of
packed red blood cells (pRBCs) during transport. Primary outcome was first ED fibrinogen level, which, for statistical analyses,
was transformed to a binomial variable (<1.6g/L and > 1.6g/L)
based on provincial transfusion thresholds. Direct multivariate
logistic regression was used. Sixty-five patients were evaluated
for outcomes associations. These are the independent variables:
systolic blood pressure (sBP)<90 with EMS before resuscitation; sBP <90 after crystalloid administration but before pRBCs;
sBP<90 after pRBC infusion; shock index (SI); and sBP. Odds
ratios and 95% confidence intervals were reported for all significant associations.
Results: Ongoing sBP<90 after pRBC was a significant predictor of low fibrinogen, p = .03: with 7.4(1.2 – 45.89) times
greater odds of fibrinogen < 1.6g/l. This variable also was a
significant predictor of international normalized ratio (INR) >
1.5, p = .013. Those with sBP<90 after pRBC had a 17.5(1.8 –
169.2) greater odds of having an INR > 1.5. An ED arrival SI ≥
1.5 had 8.93(1.9 – 42.6) times greater odds of having fibrinogen < 1.6 g/l than those with an ED SI < 1, p = .006. Compared
with ED SI 1 – 1.49 group, those with an ED SI ≥ 1.5 had 6.9
times greater odds of having fibrinogen < 1.6 g/l, p = .02, OR
= 6.9(1.3 – 36.1). Outcomes (alive/14-day mortality from
hemorrhage or multi-organ failure/ Mortality other causes) for
sBP < 90 post pRBC were 20/34(58.8%)/7/34(20.5%)/7/34
(20.5%) compared to not persistently hypotensive:
29/31(93.5%)/1/31(3%)/1/31(3%).
Implications and lessons learned: In major trauma patients
transported by helicopter EMS who received prehospital transfusion, persistent hypotension after prehospital blood transfusion and initial ED shock index ≥ 1.5 were both associated
with low initial ED fibrinogen levels. Identification of those
trauma patients more likely to have low fibrinogen provides
earlier opportunity for targeted intervention with fibrinogen
replacement.