Role of the massive transfusion protocol in the managementof haemorrhagic shockJ. H. WatersDepartment of Anesthesiology, Magee Womens Hospital, University of Pittsburgh Medical Center, Pittsburgh, USABritish Journal of Anaesthesia 113 (S2): ii3–ii8 (2014)

Supervisor 王審之醫師Speaker 醫六 莊奕翰

DEC 30st in 2014

Background

▪ From the experience gained during the Iraq and Afghanistan conflicts, a concept of damage control resuscitation has arisen.– Blood is delivered expeditiously to the bleeding patient, generally in a fixed

ratio.– 1 unit of packed erythrocytes to 1 unit of plasma to 1 unit of platelets

▪ At the author’s institution– PRBC: FFP: Platelet=10:6:2▪ O+ uncrossmatched packed red blood cell▪ AB plasma

Novelty

▪ Close inspection of these fixed-ratio transfusion protocol studies.– Important limitations are noted in their interpretation including a prominent

effect of survivor bias.

Borgman et al. J Trauma 2007

▪ a retrospective chart review of massive transfusion at a US Army combat support hospital.– Massive transfusion was defined as >10 RBC units in 24 h.

▪ From this nonrandomized, retrospective analysis, the authors concluded that a higher ratio of plasma to erythrocytes contributed to a better outcome.

Differences in severity on presentation

▪ What seems to have been neglected in the analysis was that the patients who received the high ratio had lower rates of thoracic and head injuries.

▪ On presentation to the combat hospital, the low ratio group was more acidotic, more coagulopathic, and more anaemic than the high ratio group.

▪ For the patients who died in the low ratio group, they did so at an average of 2 h from arrival into the combat facility;– whereas, the patients in the high ratio group died on average at 37 h and died

more commonly from sepsis, multi-organ failure, and central nervous system injury.

Cotton et al. J Trauma 2008

▪ A retrospective civilian study involving 16 level I trauma centres.– 10 units PRBC in first 24 hours– PRBC: FFP: platelet = 10:4:2

▪ Same bias: differences in severity on presentation– Truncal and head injury in 58% of the low ratio patients and 23% in the high ratio

patients.– Low ratio groups: received erythrocytes at a rate of 5.25 units per hour before

death– Fixed ratio groups: at a rate of 0.63 units per hour

Survivor bias

▪ Survivor bias is associated with having survived long enough to receive a particular therapy.

Snyder et al. J Trauma 2009

▪ more than 10 units PRBC in 24 hours.

▪ Total 134 patients were included– Nonsurvivor: higher Injury severity score and

admission base deficit.– 54% of in-hospital deaths occurred within 6

hours.

Cumulative FFP:PRBC ratio

Adjust for the survival bias

Effect of plasma on coagulation function

▪ These risks primarily relate to acute allergic reactions, transfusion related acute lung injury and transfusion associated circulatory overload.

▪ Some plasma can have an INR as high as 1.3. – The INR of transfused plasma ranges from < 1 to > 1 based on the donor and the

effect of storage.

▪ 10% increase of plasma coagulation factor concentration– 4 units of FFP(around 250ml)– the effect is much greater at higher INRs (3.0 -> 2.3; 1.5-> 1.4)

▪ Recent evidence suggests that conventional laboratory tests of coagulation are insensitive in detection acquired coagulopathy as in trauma, or in guiding procoagulant therapy.

Adverse effects of aggressive plasma use

▪ Transfusion increased the survival in a patient population where 50% of the patients were predicted to die; whereas, the plasma transfusion increased the risk of death in a cohort of patients that had a predicted risk of death <20%.

▪ An increased risk of multiple organ failure when patients were transfused aggressively with plasma.

▪ In the bleeding patient, more plasma might have unpredictable results when given using a fixed ratio strategy.

Laboratory-guided plasma use

▪ Traditional laboratory testing provides slow information.– Point of care test allows for rapid testing and resulting of coagulation data at the

point of the patient bedside.

▪ Point-of-care devices that have been used for this purpose include the thromboelastograph, the Rotem, and the Sonoclot. – Each of these devices measures viscoelastic changes in whole blood as it clots.

▪ Multiple investigators have now shown improved outcomes when using a goal-directed strategy of transfusion compared with fixed ratio strategies– In trauma patients and cardiac surgery

Conclusions

▪ The immediate benefits of plasma transfusion only outweigh the risks when a coagulopathy is severe.

▪ However, overall risks increase with escalating plasma exposure, thus affecting patient safety.

▪ Point-of-care coagulation monitoring can be used to avoid excessive allogeneic blood transfusions including plasma and its associated complications.

What I learn from this……

▪ Point-of-care viscoelastic testing of whole blood coagulation provides an individualized approach to reduce unnecessary plasma transfusion and avoid associated complications.

Thx for attending