Transfusion for trauma: civilian lessons from the battlefield?

Lessons learned from the casualties of war: battlefield medicine and its implication for global trauma care

According to the Global Burden of Disease, trauma is now responsible for five million deaths each year. High-income countries have made great strides in reducing trauma-related mortality figures but low-middle-income countries have been left behind with high trauma-related fatality rates, primarily in the younger population. Much of the progress high-income countries have made in managing trauma rests on advances developed in their armed forces. This analysis looks at the recent advances in high-income military trauma systems and the potential transferability of those developments to the civilian health systems particularly in low-middle-income countries. It also evaluates some potential lifesaving trauma management techniques, proven effective in the military, and the barriers preventing these from being implemented in civilian settings.

The effectiveness of low-dose desmopressin in improving hypothermia-induced impairment of primary haemostasis under influence of aspirin - a randomized controlled trial

BACKGROUND

Mild hypothermia (34-35 °C) increases perioperative blood loss. Our previous studies showed that desmopressin could have in vitro beneficial effects on hypothermia-induced primary haemostasis impairment. In this study, we investigate the in vitro effects of desmopressin on hypothermia-induced primary haemostasis impairment under the influence of aspirin in healthy volunteers.

METHODS

Sixty healthy volunteers were randomly allocated to taking aspirin 100 mg or placebo for three days. On the sixth day blood samples were taken before and after the injection of desmopressin (1.5 microgram or 5 microgram) or normal saline subcutaneously. Measurements including Platelet Function Analyzer (PFA-100®) closure times, plasma von Willebrand Factor antigen, haemoglobin and platelet levels were made at 32 °C and 37 °C respectively.

RESULTS

Collagen/epinephrine closure time (EPICT) was significantly prolonged by 21.13 % (95 %CI 2.34-39.74 %, p = 0.021) in aspirin group at 37 °C. While hypothermia alone prolonged both collagen/adenosine diphosphate (ADPCT) and EPICT by 17.63 % (95 %CI 13.5-20.85 %, p < 0.001) and 8.0 % (95 %CI 6.38-10.04 %, p = 0.024) respectively, addition of aspirin only further prolonged EPICT by 19.9 % (95 %CI 3.32-36.49 %, p = 0.013). In aspirin group, desmopressin 1.5 microgram and 5 microgram significantly reduced ADPCT to below baseline levels at 37 °C (p = 0.025 and <0.001 respectively), whereas reduction in EPICT was seen with desmopressin 5 microgram (p =0.008). The effect was less pronounced at 32 °C, with a significant reduction in EPICT obtained with a dosage of 5 microgram only (p = 0.011).

CONCLUSION

It was shown that aspirin could further potentiate the hypothermia-induced closure time prolongations. Low dose desmopressin (1.5 microgram) reduced PFA-100® closure times towards baseline. A higher dosage (5 microgram) further reduced the closure times below baseline. Therefore low dose desmopressin (1.5 microgram) might have the potential to correct hypothermia-induced primary haemostasis impairment under the influence of aspirin during the perioperative period.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01382134.

Meta-analysis of plasma to red blood cell ratios and mortality in massive blood transfusions for trauma

BACKGROUND

The current military paradigm for blood transfusion in major trauma favours high plasma:RBC ratios. This study aimed determine whether high plasma:red blood cell (RBC) ratios during massive transfusion for trauma decrease mortality, using meta-analysis of contemporaneous groups matched for injury severity score.

METHODS

A systemic review of the published literature for massive blood transfusions in trauma was performed. Patients were categorised into groups based on plasma:RBC transfusion ratios. Meta-analysis was only performed when there were no significant differences in Injury Severity Score (ISS) between ratio groups within studies. The main endpoint was 30-day mortality.

RESULTS

Six observational studies reporting outcomes for 1885 patients were included in this meta-analysis. Five studies were from civilian environments and one from a military setting. Ratio cut-offs at 1:2 were the most commonly reported, demonstrating a survival advantage with higher ratios (OR 0.49, 95% CI 0.31-0.80, p=0.004). Ratios≥1:2 showed a significant reduction in mortality compared to lower ratios (OR 0.56, 95% CI 0.40-0.78, p<0.001). Reducing the cut-off level was still protective (ratios between 1:2.5 and 1:4, OR 0.41), although the confidence interval was wide (0.16-1.00, p=0.05) and data heterogenous (I(2)=78%). Ratios of 1:1 were not proven to confer additional benefit beyond ratios of 1:2 (OR 0.50, 95% CI 0.37-0.68, p<0.001).

CONCLUSIONS

In groups matched for ISS, there was a survival benefit with high plasma:RBC resuscitation ratios. No additional benefits of 1:1 over 1:2 ratios were identified.

A retrospective study into the levels of evidence presented at the Combined Services Orthopaedic Society annual meeting

OBJECTIVES

The role of Evidence Based Medicine in clinical care is to provide a framework for the integration of expertise, current evidence and the needs of the individual patient. Research presented at scientific meetings is an important source of such evidence, informing clinical decision making both on military operations and in home nation health care systems. The aim of this study is to review the levels of evidence presented at the Combined Services Orthopaedic Society (CSOS) and two other related scientific meetings.

METHODS

Retrospective review of abstracts presented at the annual scientific meetings of the CSOS, Society of Military Orthopaedic Surgeons (SOMOS) and the British Trauma Society (BTS). Basic science studies, animal studies, cadaveric studies, surveys and guest lectures were excluded. Research abstracts were categorised according to the Centre for Evidence-Based Medicine's (CEBM) hierarchy of evidence. Statistical comparison was performed to investigate differences in evidence levels presented at each scientific meeting and between each year of the CSOS meeting.

RESULTS

596 abstracts met the inclusion criteria for this study (179 CSOS, 173 SOMOS, 244 BTS). Level IV evidence accounted for the majority of presented abstracts at each meeting (72.6% CSOS, 69.4% SOMOS, 68.9% BTS). Level I evidence was uncommon at each meeting (6.1% CSOS, 5.2% SOMOS, 2.9% BTS). There was no statistical difference in the evidence levels presented at the three scientific meetings.

CONCLUSIONS

The proportion of comparative clinical studies (Levels I-III) presented at military or trauma societies' scientific meetings reflects the difficulty of performing research in emergency surgery. This is further exacerbated in the military environment where operational commitments and delivery of care take priority. However, the future value of comparative clinical research in battlefield healthcare could have an enduring legacy that shapes trauma care for many decades.

Resuscitation and coagulation in the severely injured trauma patient

Developments in the resuscitation of the severely injured trauma patient in the last decade have been through the increased understanding of the early pathophysiological consequences of injury together with some observations and experiences of recent casualties of conflict. In particular, the recognition of early derangements of haemostasis with hypocoagulopathy being associated with increased mortality and morbidity and the prime importance of tissue hypoperfusion as a central driver to this process in this population of patients has led to new resuscitation strategies. These strategies have focused on haemostatic resuscitation and the development of the ideas of damage control resuscitation and damage control surgery continuum. This in turn has led to a requirement to be able to more closely monitor the physiological status, of major trauma patients, including their coagulation status, and react in an anticipatory fashion.