Indications and Outcomes for Adult Extracorporeal Membrane Oxygenation at a Military Referral Facility.

INTRODUCTION: Extracorporeal life support, including extracorporeal membrane oxygenation (ECMO), is a potentially life-saving adjunct to therapy in patients experiencing pulmonary and/or cardiac failure. The U.S. DoD has only one ECMO center, in San Antonio, Texas. In this study, we aimed to analyze outcomes at this center in order to determine whether they are on par with those reported elsewhere in the literature. MATERIALS AND METHODS: In this observational study, we analyzed data from patients treated with ECMO at the only DoD ECMO center between September 2012 and April 2020. The primary outcome was survival to discharge, and secondary outcomes were discharge disposition and incidence of complications. RESULTS: One hundred and forty-three patients were studied, with a 70.6% rate of survival to discharge. Of the patients who survived, 32.7% were discharged home; 32.7% were discharged to a rehabilitation facility; and 33.7% were transferred to another hospital, 29.4% of whom were transferred to lung transplant centers. One patient left against medical advice. Incidence of ECMO-related complications were as follows: 64 patients (44.7%) experienced hemorrhagic complications, 80 (55.9%) had renal complications, 61 (42.6%) experienced cardiac complications, 39 (27.3%) had pulmonary complications, and 5 patients (3.5%) experienced limb ischemia. We found that these outcomes were comparable to those reported in the literature. CONCLUSIONS: Extracorporeal membrane oxygenation can be an efficacious adjunct in management of critically ill patients who require pulmonary and/or cardiac support. This single-center observational study demonstrated that the DoD's only ECMO center has outcomes comparable with the reported data in Extracorporeal Life Support Organization's registry.

Tube Thoracostomy Complications in Patients With ARDS Requiring ECMO: Worse in COVID-19 Patients?

INTRODUCTION: The incidence and management outcomes of COVID-19 patients with acute respiratory distress syndrome (ARDS) on veno-venous extracorporeal membrane oxygenation (V-V ECMO) requiring chest tubes are not well-described. This study sought to explore differences in tube thoracostomy rates and subsequent complications between patients with and without COVID-19 ARDS on V-V ECMO. MATERIALS AND METHODS: This study is a single institution, retrospective cohort study of patients with COVID-19 ARDS requiring V-V ECMO. The control cohort consisted of patients who required V-V ECMO for ARDS-related diagnoses from January 2018 to January 2021. The primary outcome was any complication following initial tube thoracostomy placement. Study approval was obtained from the Brooke Army Medical Center Institutional Review Board (C.2017.152d). RESULTS: Twenty-five COVID-19 patients and 38 controls were included. Demographic parameters did not differ between the groups. The incidence of pneumothorax was not significantly different between the two groups (44% COVID-19 vs. 22% control, OR 2.8, 95% CI 0.95-7.9, P = 0.09). Patients with COVID-19 were as likely to receive tube thoracostomy as controls (36% vs. 24%, OR 1.8, 95% CI 0.55-5.7). Complications, however, were more likely to occur in the COVID-19 group (89% vs. 33%, OR 16, 95% CI, 1.6-201, P = 0.0498). CONCLUSIONS: Tube thoracostomy placement in COVID-19 patients with ARDS requiring V-V ECMO is common, as are complications following initial placement. Clinicians should anticipate the need for re-intervention in this patient population. Small-bore (14Fr and smaller) pigtail catheters appeared to be safe and efficacious in this setting, but further study on tube thoracostomy management in ECMO patients is needed.

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.

Experience With Trauma-Induced ARDS: A Retrospective Study of US Wartime Casualties 2003-2015.

BACKGROUND: The purpose of our study was to assess risks/ outcomes of acute respiratory distress syndrome (ARDS) in US combat casualties. We hypothesized that combat trauma patients with ARDS would have worse outcomes based on mechanism of injury (MOI) and labs/vital signs aberrancies. MATERIALS AND METHODS: We reviewed data on military Servicemembers serving in Iraq and Afghanistan from 1 January 2003 to 31 December 2015 diagnosed with ARDS by ICD-9 code. We extracted patient demographics, injury specifics, and mortality from the Department of Defense Trauma Registry (DoDTR). RESULTS: The most common MOI was an explosion, accounting for 67.6% of all injuries. Nonsurvivors were more likely to have explosion-related injuries, have higher injury severity score (ISS), higher international normalized ratio (INR), lower platelet count, greater base deficit, lower temperature, lower Glasgow Coma Scale (GCS) score, and lower pH. There was no significant difference in deaths across time. CONCLUSION: By identifying characteristics of patients with higher mortality in trauma ARDS, we can develop treatment guidelines to improve outcomes. Given the high mortality associated with trauma ARDS and relative paucity of clinical data available, we need to improve battlefield data capture to better guide practice and ultimately improve care. The management of ARDS will be increasingly relevant in prolonged casualty care (PCC; formerly prolonged field care) on the modern battlefield.

Percutaneous Pulmonary Artery Cannulation to Treat Acute Secondary Right Heart Failure While on Veno-venous Extracorporeal Membrane Oxygenation.

Right heart failure (RHF) is a common, yet difficult to manage, complication of severe acute respiratory distress syndrome requiring extracorporeal membrane oxygenation (ECMO) that is associated with increased mortality. Reports of the use of percutaneous mechanical circulatory support devices for concurrent right heart and respiratory failure are limited. This series describes the percutaneous cannulation of the pulmonary artery for conversion from veno-venous to veno-pulmonary artery return ECMO in 21 patients who developed secondary RHF. All patients cannulated between May 2019 and September 2021 were included. Either a 19 or 21 French venous cannula was placed percutaneously into the pulmonary artery via the internal jugular or subclavian vein, providing a total of 821 days of support (median 23 [4-71] days per patient) with flows up to 6 L/min. Five patients underwent cannulation at the bedside, with the remainder performed in the cardiac catheterization laboratory. Pulmonary artery cannulation occurred after 12 [8.5-23.5] days of ECMO support. Vasoactive infusion requirements decreased significantly within 24 hours of pulmonary artery cannula placement (p = 0.0004). Nonetheless, 75% of these patients expired after a median of 12 [4-63] days of support, with three patients found to have had significant pericardial effusions peri-arrest. This cannulation technique may be an effective alternative to veno-arterial ECMO cannulation or the placement of a dual-lumen cannula for the treatment of RHF.

Outcomes of Fungemia in Patients Receiving Extracorporeal Membrane Oxygenation.

There are limited data on the treatment of fungal infections complicating extracorporeal membrane oxygenation (ECMO). In 14 patients who developed fungal bloodstream infections on ECMO, 8 (57%) survived to discharge. Of the 5 patients completing treatment prior to decannulation, 2 (40%) developed recurrent fungal infections.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center.

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

Adjunct Use of Continuous Renal Replacement Therapy with Extracorporeal Membrane Oxygenation Achieves Negative Fluid Balance and Enhances Oxygenation Which Improves Survival in Critically Ill Patients without Kidney Failure.

INTRODUCTION: Fluid overload in extracorporeal membrane oxygenation (ECMO) patients has been associated with increased mortality. Patients receiving ECMO and continuous renal replacement therapy (CRRT) who achieve a negative fluid balance have improved survival. Limited data exist on the use of CRRT solely for fluid management in ECMO patients. METHODS: We performed a single-center retrospective review of 19 adult ECMO patients without significant renal dysfunction who received CRRT for fluid management. These patients were compared to a cohort of propensity-matched controls. RESULTS: After 72 h, the treatment group had a fluid balance of -3840 mL versus + 425 mL (p ≤ 0.05). This lower fluid balance correlated with survival to discharge (odds ratio 2.54, 95% confidence interval 1.10-5.87). Improvement in the ratio of arterial oxygen content to fraction of inspired oxygen was also significantly higher in the CRRT group (102.4 vs. 0.7, p ≤ 0.05). We did not observe any significant difference in renal outcomes. CONCLUSIONS: The use of CRRT for fluid management is effective and, when resulting in negative fluid balance, improves survival in adult ECMO patients without significant renal dysfunction.

Argatroban for Anticoagulation in Patients Requiring Venovenous Extracorporeal Membrane Oxygenation in Coronavirus Disease 2019.

A significant proportion of patients with coronavirus disease 2019 requiring venovenous extracorporeal membrane oxygenation at our institution demonstrated heparin resistance, which in combination with a heparin shortage resulted in the transition to argatroban with or without aspirin as an alternative anticoagulation strategy. The optimal anticoagulation strategy for coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation is unknown, and therefore, we sought to evaluate the efficacy and safety of argatroban with or without aspirin as an alternative anticoagulation strategy in this patient population. DESIGN: Retrospective cohort. SETTING: Single-center tertiary-care facility in Fort Sam Houston, TX, from 2020 to 2021. PATIENTS: Twenty-four patients who were cannulated for venovenous extracorporeal membrane oxygenation due to respiratory failure secondary to coronavirus disease 2019. INTERVENTIONS: Argatroban, with or without aspirin, was substituted for heparin in coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Eighty percent of our coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation demonstrated heparin resistance, and patients who were initially started on heparin were significantly more likely to require a change to argatroban than vice versa due to difficulty achieving or maintaining therapeutic anticoagulation goals (93.4% vs 11.1%; p < 0.0001). The time to reach the therapeutic anticoagulation goal was significantly longer for patients who were initially started on heparin in comparison with argatroban (24 vs 6 hr; p = 0.0173). Bleeding and thrombotic complications were not significantly different between the two cohorts. CONCLUSIONS: Argatroban, with or without aspirin, is an effective anticoagulation strategy for patients who require venovenous extracorporeal membrane oxygenation support secondary to coronavirus disease 2019. In comparison with heparin, this anticoagulation strategy was not associated with a significant difference in bleeding or thrombotic complications, and was associated with a significantly decreased time to therapeutic anticoagulation goal, likely as a result of high rates of heparin resistance observed in this patient population.

Development and Evaluation of An Abbreviated Extracorporeal Membrane Oxygenation (ECMO) Course for Nonsurgical Physicians and Nurses.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a modification of cardiopulmonary bypass that allows prolonged support of patients with severe respiratory or cardiac failure. ECMO indications arse rapidly evolving and there is growing interest in its use for cardiac arrest and cardiogenic shock. However, ECMO training programs are limited. Training of emergency medicine and critical care clinicians could expand the use of this lifesaving intervention. Our objective was to develop and evaluate an abbreviated ECMO course that can be taught to emergency and critical care physicians and nurses. METHODS: We developed a training model using Yorkshire swine (Sus scrofa), a procedure instruction checklist, a confidence assessment, and a knowledge assessment. Participants were assigned to teams of one emergency medicine or critical care physician and one nurse and completed an abbreviated 8-hour ECMO course. An ECMO specialist trained participants on preparation of the ECMO circuit and oversaw vascular access and ECMO initiation. We used the instruction checklist to evaluate performance. Participants completed confidence and knowledge assessments before and after the course. RESULTS: Seventeen teams (34 clinicians) completed the abbreviated ECMO course. None had previously completed an ECMO certification course. Immediately following the course, all teams successfully primed and prepared the ECMO circuit. Fifteen teams (88%, 95% confidence interval [CI] = 64% to 99%) successfully initiated ECMO. Participants improved their knowledge (difference 21.2, 95% CI = 16.5 to 25.8) and confidence (difference 40.3, 95% CI = 35.6 to 45.0) scores after completing the course. CONCLUSIONS: We developed an accelerated 1-day ECMO course. Clinicians' confidence and knowledge assessments improved and 88% of teams could successfully initiate venoarterial ECMO after the course.

A 21-Year-Old Man With a Cough.

CASE PRESENTATION: A 21-year-old male African American college student from Southern California, with no significant medical history, was visiting family in southwestern Texas when he presented to the hospital with 1 week history of cough, shortness of breath, lower back pain, and a 10-pound weight loss.

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.

Universal Anesthesia Machine: Clinical Application in an Austere, Resource-Limited Environment.

INTRODUCTION: In austere environments, the safe administration of anesthesia becomes challenging because of unreliable electrical sources, limited amounts of compressed gas, and insufficient machine maintenance capabilities. Such austere environments exist in battlefield medicine, in low- and middle-income countries (LMICs), and in areas struck by natural disasters. Whether in military operations or civilian settings, the Universal Anesthesia Machine (UAM) (Gradian Health Systems, New York, New York) is a draw-over device capable of providing safe and effective general anesthesia when external oxygen supplies or reliable electrical sources are limited. This brief report discusses a proof-of-concept observational study demonstrating the clinical utility of the UAM in a resource-limited area. MATERIALS AND METHODS: This observational study of 20 patients in Haiti who underwent general anesthesia using the UAM highlights the device's capability to deliver anesthesia intraoperatively in a resource-limited LMIC clinical setting. Preoxygenation was achieved with the UAM's draw-over oxygen supply. Patients received acetaminophen for analgesia, dexmedetomidine for preinduction anesthesia, and succinylcholine for paralysis. After induction, the UAM provided a mixture of oxygen and isoflurane for maintenance of anesthesia. Manual ventilation was performed using draw-over bellows until spontaneous ventilation recurred, when clinically appropriate, artificial airways were removed. Intraoperative medication was administered at the anesthesiologist's discretion. The institutional review board at the U.S. anesthesiologists' affiliated institution and the Haitian hospital approved this study; patients were consented in their native language. RESULTS: Two anesthesiologists used the UAM to deliver general anesthesia to 20 patients in a Haitian hospital without access to an external oxygen supply, reliable power grid, or opioids. The patients' average age was ~40 years, and 90% of them were male. Most of the cases were herniorrhaphy (50%) and hydrocelectomy (25%) surgeries. The median American Society of Anesthesiologists (ASA) score was 2; 45% of the patients had an ASA score of 1, and none had an ASA score >3. Of the 20 cases, 55% of patients received an endotracheal tube, and 40% received a laryngeal mask airway; for one patient, only a masked airway was used. Every patient was discharged on the day of the surgery. No complications occurred in the perioperative or 1-month follow-up period. CONCLUSION: The UAM can be used where a lack of resources and training exist because of its simple design, built-in oxygen concentrator, and capacity to revert from continuous-flow to draw-over anesthesia in the event of a power failure or if external oxygen supplies are unavailable. We believe the UAM addresses some of the shortcomings of modern anesthesia machines and has the potential to improve the delivery of safe general anesthesia in combat and austere scenarios. Further studies could consider different types of surgeries than those reported here and involve more complex patients. Studies involving alternative anesthetic agents and non-anesthesiologist personnel are also needed. Overall, this brief report detailing the use of the UAM following a natural disaster in a LMIC is proof of concept that the machine can provide reliable anesthesia for surgical procedures in austere and resource-limited environments, including disaster areas and modern combat zones.

Right Ventricular Failure Following Patent Foramen Ovale Closure on Venovenous-Extracorporeal Membrane Oxygenation.

We present a patient with pulmonary arterial hypertension requiring venovenous-extracorporeal membrane oxygenation for acute respiratory distress syndrome. Refractory hypoxemia secondary to right-to-left interatrial shunting via a patent foramen ovale was discovered. Right heart catheterization with invasive occlusion test heralded worsening right heart failure so closure was aborted. (Level of Difficulty: Intermediate.).

International Survey on Extracorporeal Membrane Oxygenation Transport.

Extracorporeal membrane oxygenation (ECMO) is a lifesaving therapy for severe respiratory and circulatory failure. It is best performed in high-volume centers to optimize resource utilization and outcomes. Regionalization of ECMO might require the implementation of therapy before and during transfer to the high-volume center. The aim of this international survey was to describe the manner in which interhospital ECMO transport care is organized at experienced centers. Fifteen mobile ECMO centers from nine countries participated in this survey. Seven (47%) of them operated under the "Hub-and-Spoke" model. Transport team composition varies from three to nine members, with at least one ECMO specialist (i.e., nurse or perfusionist) participating in all centers, although intensivists and surgeons were present in 69% and 50% of the teams, respectively. All centers responded that the final decision to initiate ECMO is multidisciplinary and made bedside at the referring hospital. Most centers (75%) have a quality control system; all teams practice simulation and water drills. Considering the variability in ECMO transport teams among experienced centers, continuous education, training and quality control within each organization itself are necessary to avoid adverse events and maintain a low mortality rate. A specific international ECMO Transport platform to share data, benchmark outcomes, promote standardization, and provide quality control is required.

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.