Massive Transfusion in Trauma
Dr Andrew Silvers MB, BS (Hons,), FANZCA, Senior Staff Anaesthetist, Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, Melbourne
Massive transfusion is a difficult clinical management problem. It is not only a medical treatment issue, but success is equally reliant upon logistic management as much as the application of science. The management of massive transfusion must be a planned event so the information flow is smooth and uncluttered. As result communication and coordination are paramount in this scenario. The teams involved will include, surgical, anaesthetic and haematological. Within the confines of the operating room the coordinator of the resuscitative process will be the anaesthetist. It is vital to establish good communication with these staff members and departments.
Unfortunately no universally accepted definition of massive transfusion really exists. Both volume and rate are important, and most people recognize a large bleed. The most common definition is bleeding requiring more than 10 units over a 24 hour period .Other definitions include, replacement of 50% of blood volume in 3 hours or blood loss of greater than 150 ml/min. When blood loss is so severe and rapid that blood product support exceeds compensatory mechanisms is probably a better real world definition, although not one which is readily reproducible. It is important to remember normal blood volume is approximately 7% of ideal body weight.
The other substantial problem with massive transfusion apart from the lack of a standard definition is it remains a difficult subject to study because of the clinical circumstances. As a result of this difficulty the literature contains mainly publications based on retrospective data. The other issue which confuses the data is that blood products themselves have changed in composition over time .Teaching has not always kept abreast of these developments.
Haemorrhage in traumas responsible for between 30 – 40% of mortality, with up to half occurring in the prehospital phase. The combination of acidosis, hypothermia and coagulopathy has been labelled the triad of death and it is very important in the viscous cycle of haemorrhage, resuscitation, haemodilution, coagulopathy and continued bleeding.
Differences exist between the coagulopathy a trauma patient may develop compared with the coagulopathy which may develop in the elective surgery setting. The development of coagulopathy in trauma is as much a function of the disease of trauma, whereas the coagulopathy which develops in the elective surgical setting is much more predicated on the blood volume replacement needed. The coagulopathy which manifests in trauma needs to be seen as part of the "disease of trauma". This coagulopathy may then be complicated by massive transfusion which may ensure in the hospital setting. Initial coagulation status of trauma patients may give an insight into the coagulopathy of trauma.
A retrospective analysis was conducted of initial coagulation profiles in trauma patients presenting to the Alfred Hospital over a 4 year period 2002 to 2006. The data was extracted from The Alfred Trauma Registry. Parameters analysed included the first measured platelet count, INR (International Normalized Ratio) and fibrinogen levels. A platelet count less than 150 × 109/L, an INR of › 1.4 and a fibrinogen < 1.0g/L were the critical values. The probability of an INR >1.4 on arrival ranged from 44.8% to 65.2%. The probability of a fibrinogen < 1.0g/L on arrival ranged from 12.9% to 30.8% and the probability of a platelet count less than 150 ×109/L on arrival ranged from 8.9% to 24.9%. The maximum frequency of an INR greater than 1.4 was in patients with an arrival blood pressure < 90mmHg. The maximum frequency of a fibrinogen < 1.0g/L was in patients in whom blood was administered in trauma centre in association with a trauma callout and the maximum frequency of a platelet count < l50 ×109/L was in the group of patients with an arrival blood pressure < 90mmHg systolic blood pressure. The coagulopathy begins early and is a manifestation of the trauma which may be compounded by the ongoing fluid resuscitation
Older data suggests patients requiring massive transfusion support have a rather dismal outlook. Some suggest that the magnitude of blood product support be used as an indicator of futility and hence be used to as a guide to cease therapy. Does the modern era of resuscitation still support this opinion? Multiple studies have suggested the outcome from massive transfusion has improved over time. This may be related to aggressive correction of coagulopathy, more efficient use of warming measures, decreased operative times for the initial operation, and increased use of component therapy. Recombinant activated factor VII (factor VIIa) is a prohaemostatic agent that can be used for patients with complicated coagulation disorders. Recombinant factor VIIa is, however, increasingly used for several other indications, including patients with a preexistent normal coagulation system but who experience serious surgical bleeding.
Only one randomized control trial has demonstrated efficacy of this agent when given prophylactically.
A randomized double blind parallel study by Boffard et al evaluated the efficacy and safety of recombinant factor VIIa as adjunctive therapy for control of bleeding in patients with severe blunt or penetrating trauma. The only reported advantage was in the blunt injury group with a reduction in red cells transfused. No survival advantage was described in any group. Of note, was the retrospective exclusion of patients from the data analysis which died in the first 48 hours. Although the drug was given early in the patient’s treatment and haemorrhagic deaths would have accounted for a reasonable portion of those deaths in the first 48 hours. Inclusion of this group showed no statistical difference in any outcome. This trial is in the process of being repeated.
Much remains to be fully described in massive transfusion in the modern era. A greater emphasis on the epidemiology and logistic management should occur because once the complications of massive transfusion occur it is very difficult to restore the physiologic milieu. In addition new agents may play a role as adjuncts to conventional therapy in order to improve outcomes in massively transfused trauma patients.
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Time of Presentation
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