Abstract

BACKGROUND Blood transfusion is common in the resuscitation of patients with traumatic injury. However, the clinical impact of the length of storage of transfused blood is unclear in this population. STUDY DESIGN AND METHODS We undertook a prespecified nested analysis of 372 trauma victims of the 2510 critically ill patients from 64 centers treated as part of the Age of Blood Evaluation (ABLE) randomized controlled trial. Patients were randomized according to their trauma status to receive either a transfusion of fresh blood stored not more than 7 days or standard-issue blood. Our primary outcome was 90-day all-cause mortality. RESULTS Overall, 186 trauma patients received fresh blood and 186 received standard-issue blood. Adherence to transfusion protocol was 94% (915/971) for all fresh blood transfused and 100% (753/753) for all standard-issue blood transfused. Mean +/- SD blood storage duration was 5.6 +/- 3.8 days in the fresh group and 22.7 +/- 8.4 days in the standard-issue group (p < 0.001). Ninety-day mortality in the fresh group was 21% (38/185), compared to 16% (29/184) in the standard-issue group, with an unadjusted absolute risk difference of 5% (95% confidence interval [CI], -3.1 to 12.6) and an adjusted absolute risk difference of 2% (95% CI, -3.5 to 6.8). CONCLUSION In critically ill trauma patients, transfusion of fresh blood did not decrease 90-day mortality or secondary outcomes, a finding similar to the overall population of the ABLE trial.

Abstract

Tranexamic acid (TXA) is an effective hemostatic agent used for the reduction of blood loss and transfusion. However, the safety profile of TXA remains in question due to a potential increased risk of venous thromboembolism. By applying TXA topically as opposed to intravenously, systemic absorption may be reduced and unwanted side-effects mitigated. The objective of our review is to investigate the efficacy and safety of topically applied tranexamic acid compared to both placebo, and the intravenous administration. Cochrane Central Register of Controlled Trials, MEDLINE, Embase, ISI Web of Science, PubMed, and Clinicaltrials.gov were searched from inception to November, 2016. We included randomized controlled trials that compared topical tranexamic acid to either placebo (or standard care) or intravenous administration, in adult patients. Surgical and non-surgical trials were included. Abstract, full-text selection, data extraction and risk of bias assessment were all performed in duplicate. In total, 67 studies involving 6,034 patients met inclusion criteria. The majority of trials evaluated orthopedic procedures. Compared to placebo, the administration of topical TXA significantly reduced the odds of receiving a blood transfusion (pooled OR 0.28, 95% CI 0.20 to 0.38; P < 0.001) and significantly reduced mean blood loss (WMD -276.6, 95% CI -327.8 to -225.4; P < 0.0001). When compared to the intravenous administration, there was no difference between the two groups in terms of transfusion requirements (pooled OR 1.03, 95% CI 0.72 to 1.46; P=0.88) or blood loss (WMD -21.95, 95% CI -66.61 to 27.71; P=0.34). There was no difference in the odds of developing a venous thromboembolic complication between the topical TXA and control groups (pooled OR=0.78, 95% CI 0.47 to 1.29; P=0.33) or the topical and intravenous groups (pooled OR=0.75, 95% CI 0.39 to 1.46; P=0.40). The topical application of TXA effectively reduces both transfusion risk and blood loss compared to placebo, without increasing thromboembolic risks. There were no major differences between topical and intravenous tranexamic acid with respect to safety and efficacy, and both were superior to placebo with regards to blood loss and transfusion requirements. Further study of the topical application is required outside of the field of orthopedics.

Abstract

BACKGROUND Several new trials evaluating transfusion strategies in patients with cardiovascular disease have recently been published, increasing the number of enrolled patients by over 30%. The objective was to evaluate transfusion thresholds in patients with cardiovascular disease. METHODS We conducted an updated systematic review of randomized trials that compared patients assigned to maintain a lower (restrictive transfusion strategy) or higher (liberal transfusion strategy) hemoglobin concentration. We focused on new trial data in patients with cardiovascular disease. The primary outcome was 30-day mortality. Specific subgroups were patients undergoing cardiac surgery and with acute myocardial infarction. RESULTS A total of 37 trials that enrolled 19,049 patients were appraised. In cardiac surgery, mortality at 30days was comparable between groups (risk ratio 0.99; 95% confidence interval 0.74-1.33). In 2 small trials (n=154) in patients with myocardial infarction, the point estimate for the mortality risk ratio was 3.88 (95% CI, 0.83-18.13) favoring the liberal strategy. Overall, from 26 trials enrolling 15,681 patients, 30-day mortality was not different between restrictive and liberal transfusion strategies (risk ratio 1.0, 95% CI, 0.86-1.16). Overall and in the cardiovascular disease subgroup, there were no significant differences observed across a range of secondary outcomes. CONCLUSIONS New trials in patients undergoing cardiac surgery establish that a restrictive transfusion strategy of 7 to 8g/dL is safe and decreased red cell use by 24%. Further research is needed to define the optimal transfusion threshold in patients with acute myocardial infarction.