Blood transfusions in mass casualty events: recent trends

A systematic review of hemorrhage and vascular injuries in civilian public mass shootings

BACKGROUND

Civilian public mass shootings (CPMSs) are a major public health issue and in recent years several events have occurred worldwide. The aim of this systematic review was to characterize injuries and mortality after CPMSs focusing on in-hospital management of hemorrhage and vascular injuries.

METHOD

A systematic review of all published literature was undertaken in Medline, Embase and Web of Science January 1st, 1968, to February 22nd, 2021, according to the PRISMA guidelines. Literature was eligible for inclusion if the CPMS included three or more people shot, injured or killed, had vascular injuries or hemorrhage.

RESULTS

The search identified 2884 studies; 34 were eligible for inclusion in the analysis. There were 2039 wounded in 45 CPMS events. The dominating anatomic injury location per event was the extremity followed by abdomen and chest. The median number of operations and operated patients per event was 22 (5-101) and 10.5 (4-138), respectively. A total of 899 deaths were reported with a median mortality rate of 36.1% per event (15.9-71.4%) Thirty-eight percent (13/34) of all studies reported on vascular injuries. Vascular injuries ranged from 8 to 29%; extremity vascular injury the most frequent. Specific vascular injuries included thoracic aorta 18% (42/232), carotid arteries 6% (14/232), and abdominal aorta 5% (12/232). Vascular injuries were involved in 8.3%-10% of all deaths.

CONCLUSION

This systematic review showed an overall high mortality after CPMS with injuries mainly located to the extremities, thorax and abdomen. About one quarter of deaths was related to hemorrhage involving central large vessel injuries. Further understanding of these injuries, and structured and uniform reporting of injuries and treatment protocols may help improve evaluation and management in the future. Level of Evidence Systematic review and meta-analysis, level III.

Novel blood derived hemostatic agents for bleeding therapy and prophylaxis

PURPOSE OF REVIEW

Hemorrhage is a major cause of preventable death in trauma and cancer. Trauma induced coagulopathy and cancer-associated endotheliopathy remain major therapeutic challenges. Early, aggressive administration of blood-derived products with hypothesized increased clotting potency has been proposed. A series of early- and late-phase clinical trials testing the safety and/or efficacy of lyophilized plasma and new forms of platelet products in humans have provided light on the future of alternative blood component therapies. This review intends to contextualize and provide a critical review of the information provided by these trials.

RECENT FINDINGS

The beneficial effect of existing freeze-dried plasma products may not be as high as initially anticipated when tested in randomized, multicenter clinical trials. A next-generation freeze dried plasma product has shown safety in an early phase clinical trial and other freeze-dried plasma and spray-dried plasma with promising preclinical profiles are embarking in first-in-human trials. New platelet additive solutions and forms of cryopreservation or lyophilization of platelets with long-term shelf-life have demonstrated feasibility and logistical advantages.

SUMMARY

Recent trials have confirmed logistical advantages of modified plasma and platelet products in the treatment or prophylaxis of bleeding. However, their postulated increased potency profile remains unconfirmed.

U.S. cities will not meet blood product resuscitation standards during major mass casualty incidents: Results of a THOR-AABB working party prospective analysis

BACKGROUND

Mass casualty incidents (MCIs) create an immediate surge in blood product demand. We hypothesize local inventories in major U.S. cities would not meet this demand.

STUDY DESIGN AND METHODS

A simulated blast in a large crowd estimated casualty numbers. Ideal resuscitation was defined as equal amounts of red blood cells (RBCs), plasma, platelets, and cryoprecipitate. Inventory was prospectively collected from six major U.S. cities at six time points between January and July 2019. City-wide blood inventories were classified as READY (>1 U/injured survivor), DEFICIENT (<10 U/severely injured survivor), or RISK (between READY and DEFICIENT), before and after resupply from local distribution centers (DC), and features of DEFICIENT cities were identified.

RESULTS

The simulated blast resulted in 2218 injured survivors including 95 with severe injuries. Balanced resuscitation would require between 950 and 2218 units each RBC, plasma, platelets and cryoprecipitate. Inventories in 88 hospitals/health systems and 10 DCs were assessed. Of 36 city-wide surveys, RISK inventories included RBCs (n = 16; 44%), plasma (n = 24; 67%), platelets (n = 6; 17%), and cryoprecipitate (n = 22; 61%) while DEFICIENT inventories included platelets (n = 30; 83%) and cryoprecipitate (n = 12; 33%). Resupply shifted most RBC and plasma inventories to READY, but some platelet and cryoprecipitate inventories remained at RISK (n = 24; 67% and n = 12; 33%, respectively) or even DEFICIENT (n = 11; 31% and n = 6; 17%, respectively). Cities with DEFICIENT inventories were smaller (p <.001) with fewer blood products per trauma bed (p <.001).

DISCUSSION

In this simulated blast event, blood product demand exceeded local supply in some major U.S. cities. Options for closing this gap should be explored to optimize resuscitation during MCIs.

Transfusion management of trauma from the 2019 El Paso mass shooting incident

BACKGROUND AND OBJECTIVES

Mortality rates, transfusion ratios, trauma management logistics, and assault characteristics from the El Paso mass shooting incident (MSI) are evaluated in comparison to other MSIs. In 2019, El Paso, TX experienced the eighth-deadliest MSIs in modern US history. In this 21st mass killing in the United States of 2019, 19 people died immediately, and four of 27 injured, later died from ballistic injuries.

MATERIALS AND METHODS

We examined the victims' injuries, pre-hospital treatments, transfusions, rotational thromboelastometry (ROTEM) interpretation, tranexamic acid (TXA) use, and compared El Paso's outcomes with other MSIs.

RESULTS

Fifteen casualties were treated for bullet injuries at University Medical Center (UMC). Three were in critical condition; one died during surgery. Of the remaining victims, two were guarded, and the remaining ten in stable condition. Anatomic trauma locations included chest, abdomen, hip, breast, thigh and arm. Haemostatic agents and TXA were administered to arriving patients. Seven casualties receiving blood products were administered 95 units at UMC (45 red blood cells [RBC], 38 fresh frozen plasma [FFP], 8 platelets and 4 cryoprecipitate). ROTEM guided mass transfusion decisions in three patients. Out of seven MSIs reviewed, El Paso had the highest mortality rate (50.0%) and lowest RBC:FFP:admission ratio (1.18 at UMC).

CONCLUSION

We report the greatest proportion of transfusions per admission for an MSI and are first to discuss ROTEM roles to guide transfusion and manage coagulopathy during an MSI. This case highlights the severity and impact of MSIs on victims and requirements to follow established transfusion protocols with adjunct use of ROTEM, TXA and haemostatic agents.

Transfusion support during mass casualty events

Transfusion support is an essential element of modern emergency healthcare. Blood services together with hospital transfusion teams are required to prepare for, and respond to, mass casualty events as part of wider healthcare emergency planning. Preparedness is a constant collaborative process that actively identifies and manages potential risks, to prevent such events becoming a 'disaster'. The aim of transfusion support during incidents is to provide sufficient and timely supply of blood components and diagnostic services, whilst maintaining support to other patients not involved in the event.

Assessing predictors of futility in patients receiving massive transfusions

BACKGROUND

Massive transfusions are associated with a high mortality rate, but there is little evidence indicating when such efforts are futile. The purpose of this study was to identify clinical variables that could be used as futility indicators in massively transfused patients.

METHODS

We retrospectively analyzed 138 adult surgical patients at our institution receiving a massive transfusion (2016-2019). Peak lactate and nadir pH within 24 h of massive transfusion initiation, along with other clinical variables, were assessed as predictors of the primary outcome, in-hospital mortality.

RESULTS

The overall rate of in-hospital mortality among our patient population was 52.9% (n = 73). Increasing lactate and decreasing pH were associated with greater mortality among massively transfused patients. Mortality rates were ~2-fold higher for patients in the highest lactate category (≥10.0 mmol/L: 25 of 37; 67.6%) compared to the lowest category (0.0-4.9 mmol/L: 17 of 48; 35.4%) (p = .005), and ~2.5-fold higher for patients in the lowest pH category (<7.00: 8 of 9; 88.9%) compared to the highest category (≥7.40: 8 of 23; 34.7%) (p = .016). Increasing age was also associated with higher mortality (≥65 years: 24 of 33; 72.7%) when compared to younger patients (18-64 years: 49 of 105; 46.7%) (p = .010).

CONCLUSIONS

Peak lactate ≥10.0 mmol/L, nadir pH <7.00, and age ≥65 years were significantly associated with higher rates of in-hospital mortality among massively transfused patients. Incorporating these clinical parameters into a futility index for massive transfusions will be useful in situations where blood products are scarce and/or mortality may be unavoidable.

MATRA-A: A study on massive transfusion

BACKGROUND

We use massive transfusion in various clinical conditions and it is associated with high mortality. Although some massive transfusion protocols improve patient outcomes, the clinical circumstances requiring it are not well defined.

METHODS

MATRA-A is a multicenter retrospective study. Six University and Training Research Hospitals in Ankara participated in the study. We collected clinical data on patients (>18 years) who received massive transfusions (≥10 units/24 h) from 2017 through 2019.

RESULTS

Overall, 167 (0·27% of transfused patients) received a massive transfusion of 2586 units of red blood cells (1·5% of total RBCs transfused). The median interquartile range values for RBCs, fresh frozen plasma (FFP) and platelets were 13 (11-176), 16 (9-33) and 4 (0-11), respectively. Surgical patients received 90% of massive transfusions. The most common clinical indications for massive transfusion were cardiovascular diseases (42·6%), trauma (20·3%) and malignancies (11%). FFP: RBC: Platelets ratio was 1·9:1:0·5. The overall and trauma-related mortality rates were 57·4% and 61·8%, respectively. The hospital mortality rates of trauma patients that received high vs. low ratio (FFP: RBCs > 1:1·5 vs. ≤1:1·5) transfusions were 47·6% and 86·6% and the difference was statistically significant (P = 0·03).

CONCLUSION

Cardiovascular diseases and trauma occasion are the most common causes of massive transfusion. It is infrequent in clinical settings and is associated with high mortality rates. Additionally, in massively transfused trauma patients, a high FFP:RBCs ratio seems to be associated with increased survival. Focused prospective studies are required to define the areas that need improvement on a national scale.

Pulse Arrival Time Is Associated With Hemorrhagic Volume in a Porcine Model: A Pilot Study

BACKGROUND

Hemorrhage is a major cause of preventable death worldwide, and early identification can be lifesaving. Pulse wave contour analysis has previously been used to infer hemodynamic variables in a variety of settings. We hypothesized that pulse arrival time (PAT), a form of pulse wave contour analysis which is assessed via electrocardiography (ECG) and photoplethysmography (PPG), is associated with hemorrhage volume.

METHODS

Yorkshire-Cross swine were randomized to hemorrhage (30 mL/kg over 20 minutes) vs. control. Continuous ECG and PPG waveforms were recorded with a novel monitoring device, and algorithms were developed to calculate PAT and PAT variability throughout the respiratory cycle, termed "PAT index" or "PAT_I." Mixed effects models were used to determine associations between blood loss and PAT and between blood loss and PAT_I to account for clustering within subjects and investigate inter-subject variability in these relationships.

RESULTS

PAT and PAT_I data were determined for ∼150 distinct intervals from five subjects. PAT and PAT_I were strongly associated with blood loss. Mixed effects modeling with PAT alone was substantially better than PAT_I alone (R2 0.93 vs. 0.57 and Akaike information criterion (AIC) 421.1 vs. 475.5, respectively). Modeling blood loss with PAT and PAT_I together resulted in slightly improved fit compared to PAT alone (R2 0.96, AIC 419.1). Mixed effects models demonstrated significant inter-subject variability in the relationships between blood loss and PAT.

CONCLUSIONS

Findings from this pilot study suggest that PAT and PAT_I may be used to detect blood loss. Because of the simple design of a single-lead ECG and PPG, the technology could be packaged into a very small form factor device for use in austere or resource-constrained environments. Significant inter-subject variability in the relationship between blood loss and PAT highlights the importance of individualized hemodynamic monitoring.

London 2017: Lessons learned in transfusion emergency planning

BACKGROUND AND OBJECTIVES

Hospitals prepare for emergencies, but the impact on transfusion staff is rarely discussed. We describe the transfusion response to four major incidents (MIs) during a 6-month period. Three events were due to terrorist attacks, and the fourth was the Grenfell Tower fire. The aim of this paper was to share the practical lessons identified.

METHODS

This was a retrospective review of four MIs in 2017 using patient administration systems, MI documentation and post-incident debriefs. Blood issue, usage and adverse events during the four activation periods were identified using the Laboratory Information Management System (TelePath).

RESULTS

Thirty-four patients were admitted (18 P1, 4 P2, 11 P3 and 1 dead). Forty-five blood samples were received: 24 related to nine MI P1 patients. Four P1s received blood components, three with trauma and one with burns, and 35 components were issued. Total components used were six red blood cells (RBC), six fresh frozen plasma (FFP) and two cryoprecipitate pools. Early lessons identified included sample labelling errors (4/24). Errors resolved following the deployment of transfusion staff within the emergency department. Components were over-ordered, leading to time-expiry wastage of platelets. Careful staff management ensured continuity of transfusion services beyond the immediate response period. Debriefing sessions provided staff with support and enabled lessons to be shared.

CONCLUSIONS

Transfusion teams were involved in repeated incidents. The demand for blood was minimal. Workload was related to sample handling rather than component issue. A shared situational awareness would improve stock management. A laboratory debriefing system offered valuable feedback for service improvement, staff training and support.

Maintaining adequate donations and a sustainable blood supply: Lessons learned

Background

The availability of a safe blood supply is a key component of transfusion medicine. A decade of decreased blood use, decreased payment for products, and a dwindling donor base have placed the sustainability of the US blood supply at risk.

Study Design and Methods

A literature review was performed for blood center (BC) and hospital disaster management, chronically transfusion‐dependent diseases, and appropriate use of group O‐negative red blood cells (RBCs), and the Choosing Wisely campaign. The aim was to identify current practice and to make recommendations for BC and hospital actions.

Results

While BCs are better prepared to handle disasters than after the 9/11 attacks, messaging to the public remains difficult, as donors often do not realize that blood transfused during a disaster was likely collected before the event. BCs and transfusion services should participate in drafting disaster response plans. Hospitals should maintain inventories adequate for patients in the event supply is disrupted. Providing specialty products for transfusion‐dependent patients can strain collections, lead to increased use of group O RBCs, and create logistical inventory challenges for hospitals. The AABB Choosing Wisely initiative addresses overuse of blood components to optimally use this precious resource. Group O‐negative RBCs should be transfused only to patients who truly need them.

Conclusions

Collecting and maintaining a blood supply robust enough to handle disasters and transfusion‐dependent patients in need of specialty products is challenging. Collaboration of all parties should help to optimize resources, ensure appropriate collections, improve patient care, and ultimately result in a robust, sustainable blood supply.

Frozen Platelets-Development and Future Directions

Storage requirements and outdating of platelets represent a continued challenge for blood banks. These hurdles are confounded for rural area hospitals or in military deployments. Over 60 years of research and development into frozen platelets have generated a stable and reproducible product. Valeri's method to freeze platelets in 6% dimethyl sulfoxide (DMSO) and storage at -80°C allows for long-term storage alleviating burdens placed on blood banks. Clinical studies show that frozen platelet transfusions are safe with no related thrombotic or other serious adverse events. There are ongoing efforts to demonstrate cryopreserved platelet (CPP) superiority in efficacy studies designed in trauma or cardiac surgery patients. Technical advances in CPP manufacturing including closed system manufacturing, applications of pathogen reduction technology and potency standard characterization add to the appeal of CPP as an alternative to traditional liquid-stored platelets (LP) in settings of supply shortages, mass casualty, active bleeding, rapid provision of HLA-compatible platelets, and remote care.