A Case Report of Combat Blast Injury Requiring Combat Casualty Care, Far-Forward ECMO, Air Transport, and All Levels of Military Critical Care.

We describe a 34-year-old soldier who sustained a blast injury in Syria resulting in tracheal 5 cm tracheal loss, cervical spine and cord injury with tetraplegia, multiple bilateral rib fractures, esophageal injury, traumatic brain injury, globe evisceration, and multiple extremity soft tissue and musculoskeletal injuries including a left tibia fracture with compartment syndrome. An emergent intubation of the transected trachea was performed in the field, and the patient was resuscitated with whole blood prehospital. During transport to the Role 2, the patient required cardiopulmonary resuscitation for cardiac arrest. On arrival, he underwent a resuscitative thoracotomy and received a massive transfusion exclusively with whole blood. A specialized critical care team transported the patient to the Role 3 hospital in Baghdad, and the DoD extracorporeal membrane oxygenation (ECMO) team was activated secondary to his unstable airway and severe hypoxia secondary to pulmonary blast injury. The casualty was cannulated in Baghdad approximately 40 hours after injury with bifemoral cannulae in a venovenous configuration. He was transported from Iraq to the U.S. Army Institute of Surgical Research Burn Center in San Antonio without issue. Extracorporeal membrane oxygenation support was successfully weaned, and he was decannulated on ECMO day 4. The early and en route use of venovenous ECMO allowed for maintenance of respiratory support during transport and bridge to operative management and demonstrates the feasibility of prolonged ECMO transport in critically ill combat casualties.

Early Fasciotomy and Limb Salvage and Complications in Military Lower Extremity Vascular Injury.

BACKGROUND: Military guidelines endorse early fasciotomy after revascularization of lower extremity injuries to prevent compartment syndrome, but the real-world impact is unknown. We assessed the association between fasciotomy and amputation and limb complications among lower extremitys with vascular injury. METHODS: A retrospectively collected lower extremity injury database was queried for limbs undergoing attempted salvage with vascular procedure (2004-2012). Limbs were categorized as having undergone fasciotomy or not. Injury and treatment characteristics were collected, as were intervention timing data when available. The primary outcome measure was amputation. Multivariate models examined the impact of fasciotomy on limb outcomes. RESULTS: Inclusion criteria were met by 515 limbs, 335 (65%) with fasciotomy (median 7.7 h postinjury). Of 212 limbs, 174 (84%) with timing data had fasciotomy within 30 min of initial surgery. Compartment syndrome and suspicion of elevated pressure was documented in 127 limbs (25%; 122 had fasciotomy). Tourniquet and shunt use, fracture, multiple arterial and combined arteriovenous injuries, popliteal involvement, and graft reconstruction were more common in fasciotomy limbs. Isolated venous injury and vascular ligation were more common in nonfasciotomy limbs. Fasciotomy timing was not associated with amputation. Controlling for limb injury severity, fasciotomy was not associated with amputation but was associated with limb infection, motor dysfunction, and contracture. Sixty-three percent of fasciotomies were open for >7 d, and 43% had multiple closure procedures. Fasciotomy revision (17%) was not associated with increased amputation or complications. CONCLUSIONS: Fasciotomy after military lower extremity vascular injury is predominantly performed early, frequently without documented compartment pressure elevation. Early fasciotomy is generally performed in severely injured limbs with a subsequent high rate of limb complications.

Evolution of the United States Military Extracorporeal Membrane Oxygenation Transport Team.

INTRODUCTION: The use of extracorporeal membrane oxygenation (ECMO) for the care of critically ill adult patients has increased over the past decade. It has been utilized in more austere locations, to include combat wounded. The U.S. military established the Acute Lung Rescue Team in 2005 to transport and care for patients unable to be managed by standard medical evacuation resources. In 2012, the U.S. military expanded upon this capacity, establishing an ECMO program at Brooke Army Medical Center. To maintain currency, the program treats both military and civilian patients. MATERIALS AND METHODS: We conducted a single-center retrospective review of all patients transported by the sole U.S. military ECMO program from September 2012 to December 2019. We analyzed basic demographic data, ECMO indication, transport distance range, survival to decannulation and discharge, and programmatic growth. RESULTS: The U.S. military ECMO team conducted 110 ECMO transports. Of these, 88 patients (80%) were transported to our facility and 81 (73.6%) were cannulated for ECMO by our team prior to transport. The primary indication for ECMO was respiratory failure (76%). The range of transport distance was 6.5 to 8,451 miles (median air transport distance = 1,328 miles, median ground transport distance = 16 miles). In patients who were cannulated remotely, survival to decannulation was 76% and survival to discharge was 73.3%. CONCLUSIONS: Utilization of the U.S. military ECMO team has increased exponentially since January 2017. With an increased tempo of transport operations and distance of critical care transport, survival to decannulation and discharge rates exceed national benchmarks as described in ELSO published data. The ability to cannulate patients in remote locations and provide critical care transport to a military medical treatment facility has allowed the U.S. military to maintain readiness of a critical medical asset.

Predictive survival factors of the traumatically injured on venovenous extracorporeal membrane oxygenation: A Bayesian model.

BACKGROUND: Venovenous extracorporeal membrane oxygenation (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 use 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 (CrIs) were as follows: age (e = 0.981; CrI, 0.976-0.985), ISS (e = 0.996; CrI, 0.980-1.012), P:F ratio (e = 1.000; CrI, 0.996-1.003), and time from admission to ECMO (e = 0.988; CrI, 0.974-1.004). Bayes factors (BF) were as follows: BFage = 3.151, BFISS = 3.564 × 10, BFpf = 0.463, and BFtime = 913.758. CONCLUSION: Age was the only pre-ECMO factor that demonstrated the most certain effect on hospital mortality for trauma patients placed on venovenous ECMO. The ISS and time to ECMO initiation had some appreciable impact on survival although less certain than age; P:F ratio likely had none. However, the pre-ECMO factors that were found to have any impact on mortality were relatively diminutive. More studies are necessary to update prior distributions and enhance accuracy. LEVEL OF EVIDENCE: Prognostic, Level IV.

Outcomes among Patients Treated with Renal Replacement Therapy during Extracorporeal Membrane Oxygenation: A Single-Center Retrospective Study.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) are modalities used in critically ill patients suffering organ failure and metabolic derangements. Although the effects of CRRT have been extensively studied, the impact of simultaneous CRRT and ECMO is less well described. The purpose of this study is to evaluate the incidence and the impact of CRRT on outcomes of patients receiving ECMO. METHODS: A single center, retrospective chart review was conducted for patients receiving ECMO therapy over a 6-year period. Patients who underwent combined ECMO and CRRT were compared to those who underwent ECMO alone. Intergroup -statistical comparisons were performed using Wilcoxon/Kruskal-Wallis and chi-square tests. Logistic regression was performed to identify independent risk factors for mortality. RESULTS: The demographic and clinical data of 92 patients who underwent ECMO at our center were reviewed including primary diagnosis, indications for and mode of ECMO support, illness severity, oxygenation index, vasopressor requirement, and presence of acute kidney injury. In those patients that required ECMO with CRRT, we reviewed urine output prior to initiation, modality used, prescribed dose, net fluid balance after 72 h, requirement of renal replacement therapy (RRT) at discharge, and use of diuretics prior to RRT initiation. Our primary endpoint was survival to hospital discharge. During the study period, 48 patients required the combination of ECMO with CRRT. Twenty-nine of these patients survived to hospital discharge. Of the 29 survivors, 6 were dialysis dependent at hospital discharge. The mortality rate was 39.5% with combined ECMO/CRRT compared to 31.4% among those receiving ECMO alone (p = 0.074). Of those receiving combined therapy, nonsurvivors were more likely to have a significantly positive net fluid balance at 72 h (p = 0.001). A multivariate linear regression analysis showed net positive fluid balance and increased age were independently associated with mortality. CONCLUSIONS: Use of CRRT is prevalent among patients undergoing ECMO, with over 50% of our patient population receiving combination therapy. Fluid balance appears to be an important variable associated with outcomes in this cohort. Rates of renal recovery and overall survival were higher compared to previously published reports among those requiring combined ECMO/CRRT.

Infections in patients with burn injuries receiving extracorporeal membrane oxygenation.

INTRODUCTION: Extracorporeal Membrane Oxygenation (ECMO) has only recently been described in patients with burn injuries. We report the incidence and type of infections in critically ill burn and non-burn patients receiving ECMO. METHODS: A retrospective chart review was performed on all patients at Brooke Army Medical Center who received ECMO between September 2012 and May 2018. RESULTS: 78 patients underwent ECMO. Approximately half were men with a median age of 34 years with a median time on ECMO of 237 h (IQR 121-391). Compared to patients without burns (n = 58), patients with burns (n = 20) had no difference in time on ECMO, but had more overall infections (86 vs. 31 per 1000 days, p = 0.0002), respiratory infections (40 vs. 15 per 1000 days, p = 0.01), skin and soft tissue infections (21 vs. 5 per 1000 days, p = 0.02) and fungal infections (35% vs 10%, p = 0.02). Twenty percent of bacterial burn infections were due to drug resistant organisms. CONCLUSION: This is the first study to describe the incidence of infection in burn injury patients who are undergoing ECMO. We observed an increase in infections in burn patients on ECMO compared to non-burn patients. ECMO remains a viable option for critically ill patients with burn injuries.

Military-to-civilian translation of battlefield innovations in operative trauma care.

BACKGROUND: Historic improvements in operative trauma care have been driven by war. It is unknown whether recent battlefield innovations stemming from conflicts in Iraq/Afghanistan will follow a similar trend. The objective of this study was to survey trauma medical directors (TMDs) at level 1-3 trauma centers across the United States and gauge the extent to which battlefield innovations have shaped civilian practice in 4 key domains of trauma care. METHODS: Domains were determined by the use of a modified Delphi method based on multiple consultations with an expert physician/surgeon panel: (1) damage control resuscitation (DCR), (2) tourniquet use, (3) use of hemostatic agents, and (4) prehospital interventions, including intraosseous catheter access and needle thoracostomy. A corresponding 47-item electronic anonymous survey was developed/pilot tested before dissemination to all identifiable TMD at level 1-3 trauma centers across the US. RESULTS: A total of 245 TMDs, representing nearly 40% of trauma centers in the United States, completed and returned the survey. More than half (n = 127; 51.8%) were verified by the American College of Surgeons. TMDs reported high civilian use of DCR: 95.1% of trauma centers had implemented massive transfusion protocols and the majority (67.7%) tended toward 1:1:1 packed red blood cell/fresh-frozen plasma/platelets ratios. For the other 3, mixed adoption corresponded to expressed concerns regarding the extent of concomitant civilian research to support military research and experience. In centers in which policies reflecting battlefield innovations were in use, previous military experience frequently was acknowledged. CONCLUSION: This national survey of TMDs suggests that military data supporting DCR has altered civilian practice. Perceived relevance in other domains was less clear. Civilian academic efforts are needed to further research and enhance understandings that foster improved trauma surgeon awareness of military-to-civilian translation.