Dr Akshay Shah, Adult Intensive Care Unit, John Radcliffe Hospital, Oxford
What is known?
Post-partum haemorrhage (PPH) is a leading cause of maternal morbidity and mortality worldwide. Fibrinogen is an essential component of haemostasis and fibrinogen levels of <2 g.L-1, in patients with PPH, have been shown to predict further severe bleeding and requirement for blood and blood products. Current guidelines recommend using fibrinogen concentrate to correct acquired hypofibrinogenaemia although high quality evidence for this is lacking. A recent Cochrane review demonstrated weak evidence for fibrinogen concentrate in reducing transfusion requirements in bleeding patients undergoing elective cardiac surgery.
What did this paper set out to examine?
This was a multicentre randomised placebo-controlled study aimed to assess the efficacy of pre-emptive treatment with fibrinogen concentrate early in PPH without any laboratory evidence of hypofibrinogenaemia. This is different to previous studies that have examined the use of fibrinogen concentrate once coagulopathy and a fibrinogen deficit have been established. Patients aged >18 years with a PPH, defined as bleeding from the uterus and/or birth canal with 24 hours of delivery were randomised to receive a fixed dose of 2g of fibrinogen concentrate or placebo (isotonic saline). The primary outcome was red blood cell (RBC) transfusion during a 6-week follow-up period postpartum.
What did they show?
Data from 244 patients were available for final analysis; 123 in the fibrinogen group and 121 in the placebo group. There was no difference in the primary outcome RBC transfusion was given to 25 patient (20.3%) in the fibrinogen group and 26 patients (21.5%) in the placebo group. There was also no difference in clinically important secondary outcomes such as estimated blood loss, adverse effects and progression to severe PPH between both groups. An important limitation of this study is that patients who may stand to benefit the most from fibrinogen therapy were either under-represented or not included only 2.2% of patients had a critical fibrinogen level of <2 g.L-1 and 46 patients 15% of the bleeding population in this study, could not be randomised because they were bleeding too heavily and therefore informed consent could not be obtained. Furthermore, the difference in fibrinogen concentrate between the treated and placebo group was only 0.4 g.L-1 which suggests that a larger dose may be required.
What are the implications for practice and for future work?
This study highlights the lack of benefit of fibrinogen concentrate in patients with early PPH and a normal fibrinogen level, which may help, limits it use. Future research should be directed towards developing fast and accurate tests for measuring fibrinogen levels and developing 'goal-directed’ therapy towards patients who may benefit the most such as those with severe PPH and/or acquired hypofibrinogenaemia.
BACKGROUND In early postpartum haemorrhage (PPH), a low concentration of fibrinogen is associated with excessive subsequent bleeding and blood transfusion. We hypothesized that pre-emptive treatment with fibrinogen concentrate reduces the need for red blood cell (RBC) transfusion in patients with PPH. METHODS In this investigator-initiated, multicentre, double-blinded, parallel randomized controlled trial, we assigned subjects with severe PPH to a single
dose of fibrinogen concentrate or placebo (saline). A dose of 2 g or equivalent was given to all subjects independent of body weight and the fibrinogen concentration at inclusion. The primary outcome was RBC transfusion up to 6 weeks postpartum. Secondary outcomes were total blood loss, total amount of blood transfused, occurrence of rebleeding, haemoglobin <58 g litre(-1), RBC transfusion within 4 h, 24 h, and 7 days, and as a composite outcome of 'severe PPH', defined as a decrease in haemoglobin of >40 g litre(-1), transfusion of at least 4 units of RBCs, haemostatic intervention (angiographic embolization, surgical arterial ligation, or hysterectomy), or maternal death. RESULTS Of the 249 randomized subjects, 123 of 124 in the fibrinogen group and 121 of 125 in the placebo group were included in the intention-to-treat analysis. At inclusion the subjects had severe PPH, with a mean blood loss of 1459 (sd 476) ml and a mean fibrinogen concentration of 4.5 (sd 1.2) g litre(-1). The intervention group received a mean dose of 26 mg kg(-1) fibrinogen concentrate, thereby significantly increasing fibrinogen concentration compared with placebo by 0.40 g litre(-1) (95% confidence interval, 0.15-0.65; P=0.002). Postpartum blood transfusion occurred in 25 (20%) of the fibrinogen group and 26 (22%) of the placebo group (relative risk, 0.95; 95% confidence interval, 0.58-1.54; P=0.88). We found no difference in any predefined secondary outcomes, per-protocol analyses, or adjusted analyses. No thromboembolic events were detected. CONCLUSIONS We found no evidence for the use of 2 g fibrinogen concentrate as pre-emptive treatment for severe PPH in patients with normofibrinogenaemia. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov: http://clinicaltrials.gov/show/NCT01359878. Published protocol: http://www.trialsjournal.com/content/pdf/1745-6215-13-110.pdf.Copyri ght The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: firstname.lastname@example.org.