Whole Blood Transfusion: Past, Present, and Future

Using microfluidic shear to assess transfusion requirements in trauma patients

Background

Viscoelastic assays have widely been used for evaluating coagulopathies but lack the addition of shear stress important to in vivo clot formation. Stasys technology subjects whole blood to shear forces over factor-coated surfaces. Microclot formation is analyzed to determine clot area (CA) and platelet contractile forces (PCFs). We hypothesize the CA and PCF from this novel assay will provide information that correlates with trauma-induced coagulopathy and transfusion requirements.

Methods

Blood samples were collected on adult trauma patients from a single-institution prospective cohort study of high-level activations. Patient and injury characteristics, transfusion data, and outcomes were collected. Thromboelastography, coagulation studies, and Stasys assays were run on paired samples collected at admission. Stasys CA and PCFs were quantified as area under the curve calculations and maximum values. Normal ranges for Stasys assays were determined using healthy donors. Data were compared using Kruskal-Wallis tests and simple linear regression.

Results

From March 2021 to January 2023, 108 samples were obtained. Median age was 37.5 (IQR 27.5-52) years; patients were 77% male. 71% suffered blunt trauma, 26% had an Injury Severity Score of ≥25. An elevated international normalized ratio significantly correlated with decreased cumulative PCF (p=0.05), maximum PCF (p=0.05) and CA (p=0.02). Lower cumulative PCF significantly correlated with transfusion of any products at 6 and 24 hours (p=0.04 and p=0.05) as well as packed red blood cells (pRBCs) at 6 and 24 hours (p=0.04 and p=0.03). A decreased maximum PCF showed significant correlation with receiving any transfusion at 6 (p=0.04) and 24 hours (p=0.02) as well as transfusion of pRBCs, fresh frozen plasma, and platelets in the first 6 hours (p=0.03, p=0.03, p=0.03, respectively).

Conclusions

Assessing coagulopathy in real time remains challenging in trauma patients. In this pilot study, we demonstrated that microfluidic approaches incorporating shear stress could predict transfusion requirements at time of admission as well as requirements in the first 24 hours.

Level of evidence

Level II.

Maintaining a whole blood-centered transfusion improves survival in hemorrhagic resuscitation

BACKGROUND

Whole blood (WB) transfusion has been shown to improve mortality in trauma resuscitation. The optimal ratio of packed red blood cells (pRBC) to WB in emergent transfusion has not been determined. We hypothesized that a low pRBC/WB transfusion ratio is associated with improved survival in trauma patients.

METHODS

We analyzed the 2021 Trauma Quality Improvement Program (TQIP) database to identify patients who underwent emergent surgery for hemorrhage control and were transfused within 4 hours of hospital arrival, excluding transfers or deaths in the emergency department. We stratified patients based on pRBC/WB ratios. The primary outcome was mortality at 24 hours. Logistic regression was performed to estimate odds of mortality among ratio groups compared with WB alone, adjusting for injury severity, time to intervention, and demographics.

RESULTS

Our cohort included 17,562 patients; of those, 13,678 patients had only pRBC transfused and were excluded. Fresh frozen plasma/pRBC ratio was balanced in all groups. Among those who received WB (n = 3,884), there was a significant increase in 24-hour mortality with higher pRBC/WB ratios (WB alone 5.2%, 1:1 10.9%, 2:1 11.8%, 3:1 14.9%, 4:1 20.9%, 5:1 34.1%, p = 0.0001). Using empirical cutpoint estimation, we identified a 3:1 ratio or less as an optimal cutoff point. Adjusted odds ratios of 24-hour mortality for 4:1 and 5:1 groups were 2.85 (95% confidence interval [CI], 1.19-6.81) and 2.89 (95% CI, 1.29-6.49), respectively. Adjusted hazard ratios of 24-hour mortality were 2.83 (95% CI, 1.18-6.77) for 3:1 ratio, 3.67 (95% CI, 1.57-8.57) for 4:1 ratio, and 1.97 (95% CI, 0.91-4.23) for 5:1 ratio.

CONCLUSION

Our analysis shows that higher pRBC/WB ratios at 4 hours diminished survival benefits of WB in trauma resuscitation. Further efforts should emphasize this relationship to optimize trauma resuscitation protocols.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Prehospital Freeze-Dried Plasma in Trauma: A Critical Review

Major traumatic hemorrhage is now frequently treated by early hemostatic resuscitation on hospital arrival. Prehospital hemostatic resuscitation could therefore improve outcomes for bleeding trauma patients, but there are logistical challenges. Freeze-dried plasma (FDP) offers indisputable logistical advantages over conventional blood products, such as long shelf life, stability at ambient temperature, and rapid reconstitution without specialized equipment. We sought high level, randomized, controlled evidence of FDP clinical efficacy in trauma. A structured systematic search of MEDLINE/PubMed was carried out and identified 52 relevant English language publications. Three studies involving 607 patients met our criteria: Resuscitation with Blood Products in Patients with Trauma-related Hemorrhagic Shock receiving Prehospital Care (RePHILL, n = 501); Prehospital Lyophilized Plasma Transfusion for Trauma-Induced Coagulopathy in Patients at Risk for Hemorrhagic Shock (PREHO-PLYO, n = 150); and a pilot Australian trial (n = 25). RePHILL found no effect of FDP plus packed red blood cells (PRBC) concentrate transfusion versus saline on mortality. PREHO-PLYO found no effect of FDP versus saline on International Normalized Ratio (INR) at hospital arrival. The pilot trial found that study of PRBC versus PRBC plus FDP was feasible during long air transport times to an Australian trauma centre. Further research is required to determine under what conditions FDP might provide prehospital benefit to trauma patients.

Whole blood transfusion and paroxysmal nocturnal haemoglobinuria meet again: Minor incompatibility, major trouble

BACKGROUND AND OBJECTIVES

The field of transfusion medicine started out with whole blood transfusion to treat severe anaemia and other deficiencies, and then transitioned to component therapy, largely leaving the practice, and experiences, of whole blood transfusions behind. Currently, the field is circling back and whole blood is gaining ground as an alternative to massive transfusion protocols.

MATERIALS AND METHODS

Herein we describe a severely anaemic paroxysmal nocturnal haemoglobinuria (PNH) patient initially suspected of suffering from renal haemorrhage, receiving a standard low-titre group O whole blood transfusion during pre-hospital transportation.

RESULTS

Following the transfusion, the patient suffered a clinically unmistakable haemolytic transfusion reaction requiring supportive treatment in the intensive care unit. Clinical observations are consistent with an acute haemolytic reaction. The haemolysis was likely due to minor incompatibility between the plasma from the transfused whole blood and the patient's PNH red cells. Recovery was uneventful.

CONCLUSION

This revealed an unappreciated contraindication to minor incompatible whole blood transfusion, and prompted a discussion on the distinction between whole blood and erythrocyte concentrates, the different indications for use and the importance of emphasizing these differences. It also calls attention to patient groups where minor incompatibility can be of major importance.