Optimizing Mass Casualty Triage: Using Discrete Event Simulation to Minimize Time to Resuscitation.

BACKGROUND: Urban areas in the US are increasingly focused on mass casualty incident (MCI) response. We simulated prehospital triage scenarios and hypothesized that using hospital-based blood product inventories for on-scene triage decisions would minimize time to treatment. STUDY DESIGN: Discrete event simulations modeled MCI casualty injury and patient flow after a simulated blast event in Boston, MA. Casualties were divided into moderate (Injury Severity Score 9 to 15) and severe (Injury Severity Score >15) based on injury patterns. Blood product inventories were collected from all hospitals (n = 6). The primary endpoint was the proportion of casualties managed with 1:1:1 balanced resuscitation in a target timeframe (moderate, 3.5 U red blood cells in 6 hours; severe, 10 U red blood cells in 1 hour). Three triage scenarios were compared, including unimpeded casualty movement to proximate hospitals (Nearest), equal distribution among hospitals (Equal), and blood product inventory-based triage (Supply-Guided). RESULTS: Simulated MCIs generated a mean ± SD of 302 ± 7 casualties, including 57 ± 2 moderate and 15 ± 2 severe casualties. Nearest triage resulted in significantly fewer overall casualties treated in the target time (55% vs Equal 86% vs Supply-Guided 91%, p < 0.001). These differences were principally due to fewer moderate casualties treated, but there was no difference among strategies for severe casualties. CONCLUSIONS: In this simulation study comparing different triage strategies, including one based on actual blood product inventories, nearest hospital triage was inferior to equal distribution or a Supply-Guided strategy. Disaster response leaders in US urban areas should consider modeling different MCI scenarios and casualty numbers to determine optimal triage strategies for their area given hospital numbers and blood product availability.

Open versus percutaneous tube thoracostomy with and without thoracic lavage for traumatic hemothorax: a novel randomized controlled simulation trial.

Objective: To quantify and assess the relative performance parameters of thoracic lavage and percutaneous thoracostomy (PT) using a novel, basic science 2×2 randomized controlled simulation trial. Summary background data: Treatment of traumatic hemothorax (HTX) with open tube thoracostomy (TT) is painful and retained HTX is common. PT is potentially less painful whereas thoracic lavage may reduce retained HTX. Yet, procedural time and the feasibility of combining PT with lavage remain undefined. Methods: A simulated partially clotted HTX (2%-gelatin-saline mixture) was loaded into a TT trainer and then evacuated after randomization to one of four protocols: TT+/-lavage or PT+/-lavage. Standardized inserts with fixed 28-Fr TT or 14-Fr PT positioning were used to minimize tube positioning variability. Lavage consisted of two 500 mL aliquots of warm saline after initial HTX evacuation. The primary outcome was HTX volume evacuated. The secondary outcome was additional procedural time required for the addition of the lavage. Results: A total of 40 simulated HTX trials were randomized. TT alone evacuated a median of 1236 mL (IQR 1168, 1294) leaving a residual volume of 265 mL (IQR 206, 333). PT alone resulted in a significantly greater median residual volume of 588 mL (IQR 497, 646) (p=0.002). Adding lavage resulted in similar residual volumes for TT compared with TT alone but significantly less for PT compared with PT alone (p=0.002). Lavage increased procedural time for TT by a median of 7.0 min (IQR 6.5, 8.0) vs 11.7 min (IQR 10.2, 12.0) for PT (p<0.001). Conclusion: This simulation trial characterized HTX evacuation in a standardized fashion. Adding lavage to thoracostomy placement may improve evacuation, particularly for small-diameter tubes, with little added procedural time. Further prospective clinical study is warranted. Level of evidence: NA.

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.