Predictive Survival Factors of the Traumatically Injured on Venovenous Extracorporeal Membrane Oxygenation: A Bayesian Model Background Venovenous extracorporeal membrane oxygenation (VV-ECMO) has had encouraging evidence suggesting efficacy and acceptable safety in trauma patients with refractory respiratory failure. Given the obstacles of accruing adequate quality prospective data for a resource-intensive modality, it is unclear what is indicative of survival to discharge. We investigate pre-ECMO characteristics (age, Injury Severity Score [ISS], time from admission to cannulation, P:F ratio) in trauma patients to determine correlation with survival. Methods To address these challenges, we employ Bayesian inference and patients from a level I trauma center and Extracorporeal Life Support Organization-designated Gold Center of Excellence (n=12), published literature, and Markov chain Monte Carlo simulation to determine if there is strong predictive probability regarding survival to discharge. Results Bayesian inference probabilities expressed as odds ratios with 95% credible intervals (CrI) were: age (eβage = 0.981, CrI 0.976 – 0.985), ISS (eβISS = .996, CrI 0.980 – 1.012), P:F ratio (eβpf = 1.000, CrI .996 – 1.003), and time from admission to ECMO (eβtime = 0.988, CrI 0.974 – 1.004). Bayes’ factors (BF) were: BFage = 3.151, BFISS = 3.564 x 1013, BFpf = 0.463, and BFtime = 913.758. Conclusions Age was the only pre-ECMO factor that demonstrated the most certain effect on hospital mortality for trauma patients placed on VV-ECMO. ISS and time to ECMO initiation had some appreciable impact on survival though less certain than age; P:F ratio likely had none. However, the pre-ECMO factors that were found to have any impact on mortality was relatively diminutive. More studies are necessary to update prior distributions and enhance accuracy. Level of Evidence IV – Prognostic Correspondence Address / Address for Reprints: James E. Huang, Tripler Army Medical Center – Department of Surgery, 1 Jarrett White Road, Honolulu, HI 96859 Conflict of Interest Statement: No authors have any conflicts of interest of financial disclosures. Meetings: None Sources of Funding: None © 2019 Lippincott Williams & Wilkins, Inc.

Letter to the Editor No abstract available

Cold-Stored Whole Blood: A Better Method of Trauma Resuscitation? Introduction Cold-stored whole blood (CWB) provides a balance of red blood cells, plasma, and platelets in less anticoagulant volume than standard blood component therapy (BCT). We hypothesize that patients receiving CWB along with BCT have improved survival compared to patients receiving only BCT. Methods We performed a dual-center case-match study of trauma patients who received CWB and BCT at two urban, Level-I Trauma Centers. Criteria to receive CWB included male age ≥16, female age >50, SBP<90 mmHg, and identifiable source of hemorrhage. We performed a 2:1 propensity match against any trauma patient who received ≥1u of packed red cells (PRBCs) during their initial trauma bay resuscitation. Endpoints included trauma bay mortality, 30-day mortality, laboratory values at 4 and 24 hours, and overall blood product utilization. Comparisons were made with Wilcoxon-ranked sum and Fisher’s exact test. P<0.05 was significant. Results Between both institutions, a total of 107 patients received CWB during the study period with 91 being matched to 182 BCT patients for analysis. Hemodynamic parameters of the patients in both groups at the time of presentation were similar. CWB patients had higher mean hemoglobin (10±2 g/dL vs 11±2 g/dL;p<0.001) and hematocrit (29.2±6.1% vs 32.1±5.8%;p<0.001) at 24 hours. Importantly, trauma bay mortality was less in CWB patients (8.8% v. 2.2%;p=0.039). 30-day mortality was not different in CWB patients and there were no differences in the total amount of blood products transfused at the 4-hour and 24-hour time periods. Conclusion CWB offers the benefit of a balanced resuscitation with improved trauma bay survival and higher mean hemoglobin at 24 hours. A larger, prospective study is needed to determine whether it has a longer-term survival benefit for severely injured patients. Level of Evidence III Study Type: Therapeutic Joshua P. Hazelton and Jeremy W. Cannon contributed equally to this manuscript Corresponding Author: Joshua P. Hazelton, DO, FACS, Address: Penn State Hershey Medical Center, 500 University Dr, PO Box 850, Hershey, PA 17033. Phone: 717-531-6066, Cell : 215-910-2454, Fax: 717-531-0247. Email: jhazelton@pennstatehealth.psu.edu Dr. Joshua Hazelton is the Chief Medical Officer for Z-Medica. This relationship is not in conflict with the subject matter of this manuscript. This paper was presented at the 49th Annual Meeting of the Western Trauma Association in Snowmass, Colorado on March 7th, 2019. Authors Contribution: JPH: study design, literature review, data analysis, manuscript writing, critical review JWC: study design, literature review, data analysis, manuscript writing, critical review CZ: study design, literature review, data collection, data analysis, manuscript writing, critical review JSR: literature review, data collection SAM: data collection, data analysis, critical review AJY: data collection, data analysis, critical review MS: data collection, data analysis, critical review JG: data collection, data analysis, critical review FF: data collection, data analysis, critical review AM: data collection, data analysis, critical review JG: data analysis, critical review MJS: study design, data analysis, manuscript writing, critical review JP: study design, critical review © 2019 Lippincott Williams & Wilkins, Inc.

End Tidal Carbon Dioxide Underestimates Plasma Carbon Dioxide During Emergent Trauma Laparotomy Leading to Hypoventilation and Misguided Resuscitation: A Western Trauma Association Multicenter Study Background End tidal carbon dioxide(ETCO2) is routinely used during elective surgery to monitor ventilation. The role of ETCO2 monitoring in emergent trauma operations is poorly understood. We hypothesized that ETCO2 values underestimate plasma carbon dioxide(pCO2) values during resuscitation for hemorrhagic shock. Methods Multicenter trial was performed analyzing the correlation between ETCO2 and pCO2 levels. Results 256 patients resulted in 587 matched pairs of ETCO2 and pCO2. Correlation between these two values was very poor with an R2 of 0.04. 40.2% of patients presented to the operating room acidotic and hypercarbic with a pH<7.30 and a pCO2>45mmHg. Correlation was worse in patients that were either acidotic or hypercarbic. 45% of patients have a difference of >10mmHg between ETCO2 and pCO2. A pH of <7.30 was predictive of an ETCO2 to pCO2 difference of >10mmHg. A difference of >10mmHg was predictive of mortality independent of confounders. Conclusion Nearly one half (45%) of patients were found to have an ETCO2 level greater than 10mmHg discordant from their PCO2 level. Reliance on the discordant values may have contributed to the 40% of patients in the operating room that were both acidotic and hypercarbic. Early blood gas analysis is warranted and a lower early goal of ETCO2 should be considered. Level of Evidence Level III Diagnostic test No conflicts of interest to disclose. No sources of funding to disclose. This paper was presented at the 49th Annual Meeting of the Western Trauma Association, March 3-8, 2019 in Snowmass, Colorado. Address correspondence to: Eric M. Campion, MD FACS, Assistant Professor of Surgery, Denver Health Medical Center, University of Colorado School of Medicine, 777 Bannock Street, MC 0206, Denver, CO 80204, Phone 303-602-1830, Fax 303-436-6572. E-Mail: eric.campion@dhha.org © 2019 Lippincott Williams & Wilkins, Inc.

Comparison of the Causes of Death and Wounding Patterns in Urban Firearm-Related Violence and Civilian Public Mass Shooting Events Background There are no reports comparing wounding pattern in urban and public mass shooting events (CPMS). Because CPMS receive greater media coverage, there is a connation that the nature of wounding is more grave than daily urban gun violence. We hypothesize that the mechanism of death following urban GSWs is the same as has been reported following CPMS. Methods Autopsy reports of all firearm related deaths in Washington, DC were reviewed from January 1, 2016 to December 31, 2017. Demographic data, firearm type, number and anatomic location of GSWs, and organ(s) injured were abstracted. The organ injury resulting in death was noted. The results were compared to a previously published study of 19 CPMS events involving 213 victims. Results 186 urban autopsy reports were reviewed. There were 171 (92%) homicides and 13 (7%) suicides. Handguns were implicated in 180 (97%) events. One hundred eight gunshots (59%) were to the chest/upper back, 85 (46%) to the head, 77 (42%) to an extremity, and 71 (38%) to the abdomen/lower back. The leading mechanisms of death in both urban firearm violence and CPMS were injury to the brain, lung parenchyma, and heart. Fatal brain injury was more common in CPMS events as compared to urban events involving a handgun. Conclusion There is little difference in wounding pattern between urban and CPMS firearm events. Based on the organs injured, rapid point of wounding care and transport to a trauma center remain the best options for mitigating death following all GSW events. Level of Evidence Therapeutic/Care Management, Level III. Corresponding Author: Babak Sarani, MD, FACS, FCCM 2150 Pennsylvania Ave, NW Suite 6B Washington, DC 20037 Phone: 202-741-3188 Fax: 202-741-3219 Email: bsarani@mfa.gwu.edu Disclosures: Dr. Smith and Mr. Shapiro voluntarily serve on the Executive Board of the Committee for Tactical Emergency Casualty Care. Dr. Sarani voluntarily serves on the Board of Directors of the Committee for Tactical Emergency Casualty Care. This work was presented at the 14th Annual Academic Surgical Congress (ASC) meeting, February 5-7, 2019, in Houston, Texas. Funding Source: None © 2019 Lippincott Williams & Wilkins, Inc.

It’s About Time: Transfusion Effects on Post-Injury Platelet Aggregation Over Time Background Impaired post-injury platelet aggregation is common, but the effect of transfusion on this remains unclear. Data suggests that following injury platelet transfusion may not correct impaired platelet aggregation and impaired platelet aggregation may not predict the need for platelet transfusion. We sought to further investigate platelet aggregation responses to transfusions, using regression statistics to isolate the independent effects of transfusions given in discrete time intervals from injury on both immediate and longitudinal platelet aggregation. We hypothesized that platelet aggregation response to platelet transfusion increases over time from injury. Methods Serial (0-96h) blood samples were collected from 248 trauma patients. Platelet aggregation was assessed in vitro with impedance aggregometry stimulated by adenosine diphosphate (ADP), collagen, and thrombin receptor-activating peptide-6 (TRAP). Using regression, transfusion exposure was modeled against platelet aggregation at each subsequent timepoint and adjusted for confounders (injury severity [ISS], INR, base deficit, platelet count, and interval transfusions). The expected change in platelet aggregation at each timepoint under the intervention of transfusion exposure was calculated and compared to the observed platelet aggregation. Results The 248 patients analyzed were severely injured (ISS 21 +/- 19), with normal platelet counts (mean 268x109/L +/-90), and 62% were transfused in 24 hours. The independent effect of transfusions on subsequent platelet aggregation over time was modeled with observed platelet aggregation under hypothetical treatment of one unit transfusion of blood, plasma, or platelets. Platelet transfusions had increasing expected effects on subsequent platelet aggregation over time, with the maximal expected effect occurring late (4-5 days from injury). Conclusions Controversy exists on whether transfusions improve impaired post-injury platelet aggregation. Using regression modeling, we identified that expected transfusion effects on subsequent platelet aggregation are maximal with platelet transfusion given late after injury. This is critical for tailored resuscitation, identifying a potential early period of resistance to platelet transfusion that resolves by 96 hours. Level of Evidence IV Study Type Prognostic Disclosure Information: Dr. Kornblith is supported by NIH 1K23GM130892-01, Dr. Cohen is supported by NIH UM1HL120877 and DoD W911QY-15-C-0044, Dr. Callcut is supported by NIH K01ES026834 and DoD W911QY-15-C-0044, Dr. Hendrickson is supported by K23 HL133495. Disclosure outside the scope of this work: none. Meeting presentation: To be presented at the 49th annual meeting of the Western Trauma Association; March 3 – March 8, 2019; in Snowmass, Colorado. Corresponding author: Lucy Z Kornblith, MD Zuckerberg San Francisco General Hospital 1001 Potrero Avenue Bldg. 1, Ste. 210, Box 1302 San Francisco, CA 94110 Email: lucy.kornblith@ucsf.edu Phone: (415) 206-6946 Fax: (415) 206-5484 © 2019 Lippincott Williams & Wilkins, Inc.

Assessing the Role of Urologists and General Surgeons in the Open Repair of Bladder Injuries: Analysis of a Large, Statewide Trauma Database BACKGROUND Bladder injuries often occur in the setting of polytrauma and if severe, may require open surgical repairs. We assess the role of urologists and general surgeons (GS) in the open surgical management of bladder injuries and their outcomes in a traumatic setting. METHODS Patients who underwent open bladder injury repair secondary to trauma from 2000-2017 by GS or urology were identified in the Pennsylvania Trauma Outcome Study database by ICD-9 procedure codes (57.19-57.93). Patient demographics, initial trauma assessment, length of hospital stay, associated complications and mortality were evaluated. Urology management of a bladder injury was defined by documentation of a urologist in the operating room or urological consultation during the hospital stay. GS management was defined by documented bladder repair without urology involvement as described previously. RESULTS Of 624,504 patients in the database, 701 met inclusion criteria (419 managed by urology, 282 by GS). The most commonly performed procedure was suturing of bladder lacerations (80.5%). On univariate analysis, GS was more likely to manage patients with penetrating injuries and those who required exploratory laparotomy <2 hours upon arrival. Urology was more likely to manage patients with concomitant pelvic fractures and higher injury severity score (ISS). On multivariate analysis, higher ISS was predictive of urology management (OR 1.83, 95%CI 1.17-2.87, p=0.008) while patients who required urgent exploratory laparotomy was predictive of GS management (OR 0.34, 95%CI 0.21-0.55, p<0.001). Patients with concomitant pelvic fractures (n=318) were also more likely to have higher ISS (p<0.001). Mortality, length of hospital stay and complication rates were not significantly different between the two specialties and among individual procedures. CONCLUSIONS Our study describes the landscape of traumatic bladder repairs between GS and urology. GS may maintain similar patient outcomes when managing select cases of traumatic bladder injuries even in the absence of urologists. LEVEL OF EVIDENCE Level IV (Prognostic and Epidemiological) Corresponding Author Details: Paul H. Chung, MD Assistant Professor Department of Urology Sidney Kimmel Medical College, Thomas Jefferson University 1025 Walnut Street, Suite 1112 Philadelphia, PA 19107, USA Phone: 215-955-6961; Fax: 215-923-1884 Email: paul.chung@jefferson.edu Conflicts of Interest: All authors report no COI. Posters/presentations: This paper has not been presented in any meetings Funding Source: None © 2019 Lippincott Williams & Wilkins, Inc.

A Novel Protocol to Maintain Continuous Access to Thawed Plasma at a Rural Trauma Center BACKGROUND Early administration of plasma improves mortality in massively transfused patients, but the thawing process causes delay. Small rural centers have been reluctant to maintain thawed plasma due to waste concerns. Our 254-bed rural level II trauma center initiated a protocol allowing continuous access to thawed plasma and we hypothesized its implementation would not increase waste or cost. METHODS Two units of thawed plasma are continuously maintained in the trauma bay blood refrigerator. After 3 days these units are replaced with freshly thawed plasma and returned to the blood bank for utilization prior to their 5-day expiration date. The blood bank monitors and rotates the plasma. Only trauma surgeons can use the plasma stored in the trauma bay. Wasted units and cost were measured over a 12-month period and compared to the previous 2 years. RESULTS The blood bank thawed 1127 units of plasma during the study period assigning 274 to the trauma bay. When compared to previous years, we found a significant increase in waste (p<0.001) and cost (p=0.020) after implementing our protocol. It cost approximately $125/month extra to maintain continuous access to thawed plasma during the study period. DISCUSSION A protocol to maintain thawed plasma in the trauma bay at a rural level II trauma center resulted in a miniscule increase in waste and cost when considering the scope of maintaining a trauma center. We feel this cost is also minimal when compared to the value of having immediate access to thawed plasma. Constant availability of thawed plasma can be offered at smaller rural centers without a meaningful impact on cost. LEVEL OF EVIDENCE Level III; Economic & Value-based Evaluations CORRESPONDING AUTHOR: Robert Behm, MD, FACS, Guthrie Clinic, Sayre, PA 18840, Phone: (920) 450-7433, Fax: (570) 887-4744. Robert.behm@guthrie.org We have added Burt Cagir as an author. He extensively helped with revisions. This addition was discussed with all the authors who all agree with his addition. None of the authors have any conflicts of interest to declare Presented at the 32nd EAST Annual Scientific Assembly January 17, 2019 in Austin, Tx No disclosures © 2019 Lippincott Williams & Wilkins, Inc.

THE HEALTH LITERACY OF HOSPITALIZED TRAUMA PATIENTS: WE SHOULD BE SCREENING FOR DEFICIENCIES Background Although the impact of health literacy (HL) on trauma patient outcomes remains unclear, recent studies have demonstrated that trauma patients with deficient HL have poor understanding of their injuries, are less likely to comply with follow-up, and are relatively less satisfied with physician communication. In this study, we sought to determine if HL deficiency was associated with comprehension of discharge instructions. Methods In this prospective study, hospitalized trauma patients underwent evaluation of HL prior to discharge. Newest Vital Sign (NVS) instrument was used to score HL as deficient, marginal, or proficient. Three days post discharge, patients were telephonically administered a 6-point scored questionnaire regarding comprehension of discharge instructions. A general linear model was used to determine the association between HL and comprehension of discharge instructions. Results Sixty-three patients were administered both NVS and discharge instruction questionnaire. Ten (15.9%) patients scored as deficient in HL on the NVS screen, 16 (25.4%) as marginally proficient, and 37(58.7%) as proficient. HL proficiency significantly predicted follow up score with increasing proficiency associated with higher scores on the discharge comprehension assessment (P < .001). Adjusted mean scores (± SE) for deficient, marginal, and proficient patients were 2.8 ± 0.5, 3.2 ± 0.4, and 4.7 ± 0.2. Post-hoc comparisons demonstrated significant differences between proficient with marginal proficiency (P=.002) and deficient proficiency (P=.001). Conclusions Performance on bedside test of HL among trauma inpatients predicted ability to comprehend instructions following hospital discharge. This study supports the value of HL screening prior to discharge. HL deficient patients may benefit from a transitional care program to improve comprehension of discharge instructions after leaving the hospital. Study Type PROGNOSTIC AND EPIDEMIOLOGICAL LEVEL OF EVIDENCE III The authors declare no conflicts of interest To be presented at the 49th Annual Meeting of the Western Trauma Association. March 3-8, 2019, in Snowmass, CO. Corresponding Author: Jordan A. Weinberg, MD, Division Chief, Trauma/Acute General Surgery, Trauma Administration, St. Joseph’s Hospital and Medical Center, 350 W. Thomas Road, Phoenix, AZ 85013, Tel: (602)406-3157. Email: Jordan.Weinberg@DignityHealth.org © 2019 Lippincott Williams & Wilkins, Inc.

Location, Location, Location: Utilizing NBATS-2 in Trauma System Planning INTRODUCTION In 2015, the American College of Surgeons Committee on Trauma introduced the Needs-Based Assessment of Trauma Systems (NBATS) tool to quantify the optimal number of trauma centers for a region. While useful, more focus was required on injury population, distribution, and transportation systems. Therefore, NBATS-2 was developed utilizing advanced geographical modeling. The purpose of this study was to evaluate NBATS-2 in a large regional trauma system. METHODS Data from all injured patients from 2016-2017 with an ISS > 15 was collected from the trauma registry of the existing (legacy) center. Injury location and demographics were analyzed by zip code. A regional map was built using US census data to include hospital and population demographic data by zip code. Spatial modeling was conducted using ArcGIS to estimate an area within a 45-minute drive to a trauma center. RESULTS A total of 1,795 severely injured patients were identified across 54 counties in the tri-state region. 48% of the population and 58% of the injuries were within a 45-minute drive of the legacy trauma center. With the addition of another urban center, injured and total population coverage increased by only 1% while decreasing the volume to the existing center by 40%. However, the addition of two rural trauma centers increased coverage significantly to 62% of the population and 71% of the injured (p< 0.001). The volume of the legacy center was decreased by 25%, but the self-pay rate increased by 16%. CONCLUSIONS The geospatial modeling of NBATS-2 adds a new dimension to trauma system planning. This study demonstrates how geospatial modeling applied in a practical tool can be incorporated into trauma system planning at the local level and used to assess changes in population and injury coverage within a region, as well as potential volume and financial implications to a current system. Level of Evidence Level V Study Type Observational Correspondence: Peter E. Fischer, MD, MS University of Tennessee Health Science Center Department of Surgery 910 Madison Ave, #220 Memphis, TN 38163 (901) 448-8140 pfischer@uthsc.edu No conflict of interests to declare. No disclosure on funding to declare. This paper was presented at the 32nd annual meeting of the Eastern Association for the Surgery of Trauma, January 15-19, 2019, in Austin, Texas. © 2019 Lippincott Williams & Wilkins, Inc.