Percutaneous Venopulmonary Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation.

Mechanical circulatory support (MCS) as a bridge to lung transplant is an infrequent but accepted pathway in patients who have refractory end-stage pulmonary failure. The American Association of Thoracic Surgeons Expert Consensus Guidelines, published in 2023, recommends venovenous (VV) extracorporeal membrane oxygenation (ECMO) as the initial configuration for those patients who have failed conventional medical therapy, including mechanical ventilation, while waiting for lung transplantation and needing MCS. Alternatively, venoarterial (VA) ECMO can be used in patients with acute right ventricular failure, hemodynamic instability, or refractory respiratory failure. With the advancement in percutaneous venopulmonary (VP) ECMO cannulation techniques, this option is becoming an attractive configuration as bridge to lung transplantation. This configuration enhances stability of the right ventricle, prevents recirculation with direct introduction of pulmonary artery oxygenation, and promotes hemodynamic stability during mobility, rehabilitation, and sedation-weaning trials before lung transplantation. Here, we present a case series of eight percutaneous VP ECMO as bridge to lung transplant with all patients mobilized, awake, and successfully transplanted with survival to hospital discharge.

Extracorporeal Carbon Dioxide Removal to De-escalate Venovenous Extracorporeal Membrane Oxygenation in Severe COVID-19 Acute Respiratory Distress Syndrome.

OBJECTIVES: In a subset of patients with COVID-19 acute respiratory distress syndrome (ARDS), there is a need for extracorporeal membrane oxygenation (ECMO) for pulmonary support. The primary extracorporeal support tool for severe COVID-19 ARDS is venovenous (VV) ECMO; however, after hypoxemic respiratory failure resolves, many patients experience refractory residual hypercarbic respiratory failure. Extracorporeal carbon dioxide removal (ECCO2R) for isolated hypercarbic type II respiratory failure can be used in select cases to deescalate patients from VV ECMO while the lung recovers the ability to exchange CO2. The objective of this study was to describe the authors' experience in using ECCO2R as a bridge from VV ECMO. DESIGN: Hemolung Respiratory Assist System (RAS) is a commercially available (ECCO2R) device, and the United States Food and Drug Administration accelerated its use under its Emergency Use Authorization for the treatment of refractory hypercarbic respiratory failure in COVID-19-induced ARDS. This created an environment in which selected and targeted mechanical circulatory support therapy for refractory hypercarbic respiratory failure could be addressed. This retrospective study describes the application of Hemolung RAS as a VV ECMO deescalation platform to treat refractory hypercarbic respiratory failure after the resolution of hypoxemic COVID-19 ARDS. SETTING: A quaternary-care academic medical center, single institution. PARTICIPANTS: Patients with refractory hypercarbic respiratory failure after COVID-19 ARDS who were previously supported with VV ECMO. MEASUREMENTS AND MAIN RESULTS: Twenty-one patients were placed on ECCO2R after VV ECMO for COVID-19 ARDS. Seventeen patients successfully were transitioned to ECCO2R and then decannulated; 3 patients required reescalation to VV ECMO secondary to hypercapnic respiratory failure, and 1 patient died while on ECCO2R. Five (23.8%) of the 21 patients were transitioned off of VV ECMO to ECCO2R, with a compliance of <20 (mL/cmH2O). Of these patients, 3 with low compliance were reescalated to VV ECMO. CONCLUSIONS: Extracorporeal carbon dioxide removal can be used to continue supportive methods for patients with refractory type 2 hypercarbic respiratory failure after COVID-19 ARDS for patients previously on VV ECMO. Patients with low compliance have a higher rate of reescalation to VV ECMO.

ECMO in trauma care: What you need to know.

ABSTRACT: Over the past 10 years, extracorporeal membrane oxygenation (ECMO) use in trauma patients has increased significantly. This includes adult and pediatric trauma patients and even combat casualties. Most ECMO applications are in a venovenous (VV ECMO) configuration for acute hypoxemic respiratory failure or anatomic injuries that require pneumonectomy or extreme lung rest in a patient with insufficient respiratory reserve. In this narrative review, we summarize the most common indications for VV ECMO and other forms of ECMO support used in critically injured patients, underscore the importance of early ECMO consultation or regional referral, review the technical aspects of ECMO cannulation and management, and examine the expected outcomes for these patients. In addition, we evaluate the data where it exists to try to debunk some common myths surrounding ECMO management.

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.

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.

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.

Tracheostomy Is Safe During Extracorporeal Membrane Oxygenation Support.

Patients receiving extracorporeal membrane oxygenation (ECMO) often require prolonged mechanical ventilation. Providers may be reluctant to perform tracheostomies on patients during ECMO due to their tenuous clinical status and systemic anticoagulation. We report our experience with performing open and percutaneous tracheostomies on patients supported on ECMO from August 2009 to December 2017. Of the 127 patients who underwent tracheostomy during ECMO support, the median age was 42 years (interquartile range [IQR], 29-54), 99 (78%) patients had venovenous (VV) cannulation, 22 (17%) patients had venoarterial (VA) cannulation, and six (5%) patients had hybrid configurations. Percutaneous tracheostomy was performed in 110 (87%) patients. Median-activated partial thromboplastin time (aPTT) at the time of tracheostomy was 47.5 seconds (IQR, 41-57.6 seconds). The median time from ECMO initiation to tracheostomy was 7 days (IQR, 4-11 days). A total of 55 patients (43%) received packed red blood cell (pRBC) transfusions within 48 hours after tracheostomy with a median transfusion of 2 units (IQR, 1-3). There was no procedural mortality. Overall, 88 (69%) patients survived to decannulation and 74 (58%) survived to hospital discharge. Our experience with the largest published series of tracheostomies during ECMO demonstrates that excellent outcomes can be achieved without significant morbidity.

Outcomes and Mortality Prediction Model of Critically Ill Adults With Acute Respiratory Failure and Interstitial Lung Disease.

BACKGROUND: We aimed to examine short- and long-term mortality in a mixed population of patients with interstitial lung disease (ILD) with acute respiratory failure, and to identify those at lower vs higher risk of in-hospital death. METHODS: We conducted a single-center retrospective cohort study of 126 consecutive adults with ILD admitted to an ICU for respiratory failure at a tertiary care hospital between 2010 and 2014 and who did not undergo lung transplantation during their hospitalization. We examined associations of ICU-day 1 characteristics with in-hospital and 1-year mortality, using Poisson regression, and examined survival using Kaplan-Meier curves. We created a risk score for in-hospital mortality, using a model developed with penalized regression. RESULTS: In-hospital mortality was 66%, and 1-year mortality was 80%. Those with connective tissue disease-related ILD had better short-term and long-term mortality compared with unclassifiable ILD (adjusted relative risk, 0.6; 95% CI, 0.3-0.9; and relative risk, 0.6; 95% CI, 0.4-0.9, respectively). Our prediction model includes male sex, interstitial pulmonary fibrosis diagnosis, use of invasive mechanical ventilation and/or extracorporeal life support, no ambulation within 24 h of ICU admission, BMI, and Simplified Acute Physiology Score-II. The optimism-corrected C-statistic was 0.73, and model calibration was excellent (P = .99). In-hospital mortality rates for the low-, moderate-, and high-risk groups were 33%, 65%, and 96%, respectively. CONCLUSIONS: We created a risk score that classifies patients with ILD with acute respiratory failure from low to high risk for in-hospital mortality. The score could aid providers in counseling these patients and their families.

Management of Surge in Extracorporeal Membrane Oxygenation Transport.

BACKGROUND: Transporting patients receiving extracorporeal membrane oxygenation (ECMO) support is safe and reliable with a dedicated program and established management protocols. As our program has grown, our teams have had to adapt to manage surges in transport volume while maintaining patient safety. We assessed the outcomes at peak use of our ECMO transport services during surges. METHODS: We conducted a single-center retrospective review of all patients transported to our institution while supported with ECMO from September 2008 to September 2016. Survival to discharge was the primary outcome. Surge patients were defined as those transported during months with at least 8 transports or patients transported within 24 hours of another patient in nonsurge months. RESULTS: From 2008 to 2016, 222 patients were transported to our institution while supported with ECMO. Baseline characteristics and indices of disease severity were comparable between surge and nonsurge patients. Of the 84 patients transported during surges, 59 surge patients (70%) survived to hospital discharge vs 86 (63%) of nonsurge patients (p = 0.31). Multivariable logistic regression showed that age and APACHE II (Acute Physiology and Chronic Health Evaluation) severity index score were predictors of in-hospital death (p < 0.05), but transportation during a surge was not (odds ratio, 0.91; 95% confidence interval, 0.46 to 1.80; p = 0.79). CONCLUSIONS: Patient safety and clinical outcomes can be maintained during surges in ECMO transport volume if the ECMO program has developed plans for handling transient increases in volume and considers staff fatigue and burnout. Standardizing interhospital communication, patient selection, and management protocols are critical to maintaining quality of care.

Morbid obesity is not a contraindication to transport on extracorporeal support.

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) transport has not been described in morbidly obese patients, a population that can pose significant challenges in obtaining vascular access, indexed flows and transport logistics. We sought to study the feasibility and safety of transporting obese and morbidly obese patients during extracorporeal support. METHODS: We conducted a retrospective review of all patients transported to our institution while receiving ECMO from September 2008 to September 2016. Survival to decannulation and survival to discharge were the primary outcomes. Obesity and morbid obesity were defined as a body mass index of greater than 30 kg/m2 and greater than 40 kg/m2, respectively. RESULTS: From 2008 to 2016, 222 patients were transported to our institution while receiving ECMO. Among these included patients, 131 were non-obese (interquartile range 22-27 kg/m2), 63 were obese (interquartile range 31-35 kg/m2) and 28 were morbidly obese (interquartile range 41-49 kg/m2), with 6 patients having a body mass index greater than 50 kg/m2 (range 52.3-79 kg/m2). Pre-ECMO arterial blood gases, disease severity indices, cannulation strategies and transport distances were similar between these 3 groups. There was no mortality of patients during transport, and survival to discharge was 66% (n = 87) in non-obese patients, 56% (n = 35) in obese patients and 82% (n = 23) in morbidly obese patients (P = 0.042). On multivariable logistic regression analysis, body mass index was not a predictor of in-hospital mortality (odds ratio 0.99, 95% confidence interval 0.95-1.03; P = 0.517). CONCLUSIONS: Transport of morbidly obese patients receiving ECMO may be performed safely and with excellent results in the setting of a dedicated ECMO transport programme with well-established management protocols.

Eisenmenger Syndrome and Pregnancy: Novel ECMO Configuration as a Bridge to Delivery and Recovery Utilizing a Multidisciplinary Team.

Pregnancy is typically contraindicated in Eisenmenger syndrome because of its association with excessively high maternal and fetal morbidity and mortality. Here, we report on our novel approach to successfully managing a 29 year old pregnant woman with an unrepaired patent ductus arteriosus (PDA) with Eisenmenger syndrome through delivery and recovery. Venovenous extracorporeal membrane oxygenation (ECMO) was utilized during induction of labor to stabilize maternal hemodynamics and optimize fetal oxygenation by creating an oxygenated right-to-left shunt through the PDA. Delivery ultimately required cesarean section on ECMO support, with her hospital course complicated by intraabdominal hemorrhage and, later, recannulation with venoarterial ECMO for postoperative respiratory failure with decompensated pulmonary hypertension. Ultimately, both the mother and baby were successfully discharged to home. This case highlights not only the potential for ECMO in the peripartum setting for patients with severe pulmonary hypertension, but also the complexity of management and the need for a highly experienced, multidisciplinary team.

Functional vascularized lung grafts for lung bioengineering.

End-stage lung disease is the third leading cause of death worldwide, accounting for 400,000 deaths per year in the United States alone. To reduce the morbidity and mortality associated with lung disease, new therapeutic strategies aimed at promoting lung repair and increasing the number of donor lungs available for transplantation are being explored. Because of the extreme complexity of this organ, previous attempts at bioengineering functional lungs from fully decellularized or synthetic scaffolds lacking functional vasculature have been largely unsuccessful. An intact vascular network is critical not only for maintaining the blood-gas barrier and allowing for proper graft function but also for supporting the regenerative cells. We therefore developed an airway-specific approach to removing the pulmonary epithelium, while maintaining the viability and function of the vascular endothelium, using a rat model. The resulting vascularized lung grafts supported the attachment and growth of human adult pulmonary cells and stem cell-derived lung-specified epithelial cells. We propose that de-epithelialization of the lung with preservation of intact vasculature could facilitate cell therapy of pulmonary epithelium and enable bioengineering of functional lungs for transplantation.

Awake Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation: A 9-Year Experience.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is used as a bridge to lung transplantation, but characteristics that influence its success are poorly understood. This large, single-center experience evaluated the implementation and outcomes of ECMO in this setting. METHODS: Data were collected for patients at our institution (New York-Presbyterian Hospital/Columbia University Medical Center in New York) who received ECMO as a bridge to lung transplantation from January 1, 2007 through July 10, 2016. Data were analyzed for demographics, baseline characteristics, survival, and ECMO configuration. RESULTS: Seventy-two patients received ECMO as a bridge to lung transplantation. Of the 72 patients, 40 (55.6%) underwent the transplantation procedure, 37 (92.5%) survived to discharge, and 21 (84.0%) survived for 2 years. Inotropy or vasopressor support (70% vs 93.8%; p = 0.011), Simplified Acute Physiology Score (26.8 vs 30.5; p = 0.048), and ambulation (80% vs 56.2%; p = 0.030) were significantly different between the patients who underwent lung transplantation and those who did not. Patients with cystic fibrosis were more likely to have a bridge to transplantation than patients with other lung diseases (47.5% vs 25%; p = 0.050). Daily participation in physical therapy was achieved in 50 patients (69.4%). CONCLUSIONS: This study demonstrated favorable survival in patients receiving ECMO as a bridge to lung transplantation and achieved high rates of physical therapy and avoidance of mechanical ventilation while ECMO was used in patients awaiting lung transplantation. With more than half of these patients successfully bridged to lung transplantation, we gained insight into the factors influencing patients' outcomes, including patient selection, timing of ECMO, and patient management.

Chronic thromboembolic pulmonary hypertension, pregnancy, and a pulmonary endarterectomy: a rare challenge.

It is well described that patients with group 1 forms of pulmonary arterial hypertension have a high risk of mortality during pregnancy and in the early postpartum period. However, to the authors' knowledge, the diagnosis and management of group 4 pulmonary hypertension due to chronic thromboembolic pulmonary hypertension (CTEPH) during pregnancy with early postpartum pulmonary endarterectomy (PEA) has not been previously reported. We report the case of a 28-year-old woman who received a diagnosis of CTEPH during her pregnancy, was managed as an inpatient by a multidisciplinary team throughout the pregnancy and early postpartum period, and underwent PEA 6 weeks after delivery. While the management of acute pulmonary embolus in pregnancy is well described, this unique case of CTEPH diagnosed during pregnancy illustrates several challenging management issues.

Extracorporeal Membrane Oxygenation for Cardiopulmonary Failure During Pregnancy and Postpartum.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) has been used with increasing frequency to support pregnant and postpartum patients with severe cardiac or pulmonary failure, although patient management and clinical outcomes are underreported. This study represents patients who received ECMO during the peripartum period. METHODS: All pregnant or postpartum patients treated with ECMO in the medical intensive care unit between January 1, 2009, and June 30, 2015, were included in this study. Data were analyzed retrospectively. The primary objective was to characterize the circumstances and clinical characteristics of the patients who received ECMO, describe our management during pregnancy and at the time of delivery, evaluate maternal and fetal outcomes, and report bleeding and thrombotic complications. RESULTS: Eighteen peripartum patients were treated with ECMO during the study period; 4 were pregnant at the time of cannulation. Median age was 32.6 years, and median gestational age in pregnant patients was 32 weeks. Sixteen patients (88.9%) survived to hospital discharge. Fetal survival was 14 (77.8%) in the entire cohort and 100% in patients cannulated after fetal viability. Two patients successfully delivered on ECMO. Bleeding complications developed in 6 patients (33.3%) and were associated with disseminated intravascular coagulation. No fetal complications were attributed to ECMO. CONCLUSIONS: ECMO can be used during pregnancy and postpartum with favorable maternal and fetal outcomes, and it outweighs the risk of bleeding or thrombotic complications when managed by an experienced, multidisciplinary team.

Heart Procurement from a Donor on Venovenous ECMO Support.

We report the case of a 37-year-old woman with acute respiratory distress syndrome and became a candidate for organ donation after anoxic brain injury and was on a venovenous extracorporeal membrane oxygenation (VV-ECMO) support. On preoperative evaluation and gross examination, the donor's heart was acceptable for heart transplantation to a 62-year-old female patient with a history of nonischemic cardiomyopathy with a HeartMate II mechanical assist device. Orthotopic heart transplantation was successfully performed in the recipient. We report a case that suggests that the procurement of a heart from a donor on ECMO support can potentially expand the donor heart pool in carefully selected patients.

One Hundred Transports on Extracorporeal Support to an Extracorporeal Membrane Oxygenation Center.

BACKGROUND: Extracorporeal life support technology has gained acceptance as a salvage mode for patients in respiratory or cardiac failure. Patients who are sick enough to require extracorporeal membrane oxygenation (ECMO) support are often too unstable for transfer to a hospital with ECMO capabilities. We highlight the progressive development of an ECMO transport team and the manner in which it provides reliable transport with excellent outcomes. METHODS: All data were collected retrospectively from our hospital's electronic medical record. Patient outcomes are reported through April 2, 2014. RESULTS: Our institution began an ECMO transport program in 2008, with the initial phase involving transport of highly selected patients for short distances. With experience we refined our intake and evaluation process. We also consolidated care for ECMO patients into two intensive care units and developed a dedicated ECMO intensivist position. As the program has matured, patient selection has become more inclusive and we have extended our capabilities to include interstate and international transport. All 100 patients were successfully placed on ECMO and transported to our center. Seventy-nine patients were placed on venovenous ECMO, 19 on venoarterial ECMO, and 2 on venovenous arterial ECMO. The median transport distance was 16 miles and ranged from 2.5 to 7,084 miles. CONCLUSIONS: Extracorporeal membrane oxygenation transport can be performed safely and reliably with excellent outcomes with a dedicated team that maintains stringent adherence to well-designed management protocols.

ECMO as bridge to lung transplant.

Since the advent of lung transplantation more than 5 decades ago, preoperative, surgical, and anesthetic management have improved. The growing experience with extracorporeal membrane oxygenation (ECMO) has enabled clinicians to expand its effective use to care for patients while bridging them to transplant (BTT). We highlight the approach in which ECMO is used to successfully bridge critically ill patients to lung transplantation when stringent daily clinical assessment is applied. In patients who continued to meet transplant criteria and were successfully transplanted, postoperative survival rates are acceptable. Larger studies are needed to inform decision algorithms for BTT patients and optimize outcomes.

Extracorporeal membrane oxygenation in the management of diffuse alveolar hemorrhage.

Extracorporeal membrane oxygenation (ECMO) may be used to support patients with severe hypoxemic respiratory failure refractory to conventional mechanical ventilation. However, because systemic anticoagulation is generally required to maintain circuit patency, severe bleeding is often seen as a contraindication to ECMO. We describe our center's experience with four patients who received ECMO for refractory hypoxemic respiratory failure due to diffuse alveolar hemorrhage (DAH), a condition for which anticoagulation is typically contraindicated, and provide a review of the literature. The mean age was 35.8 ± 16.4 years. The mean pre-ECMO PaO2 to FIO2 ratio was 52.3 ± 9.4 mm Hg. All patients were treated with continuous infusions of heparin with a goal-activated partial thromboplastin time between 40 and 60 seconds (mean, 47.4 ± 11.6 seconds). All four subjects (100%) survived to decannulation, and three subjects (75%) survived to discharge. The results from this case series, along with previously published data, suggest that ECMO is a reasonable management option for patients with DAH-associated severe, refractory hypoxemic respiratory failure. This is especially true in the era of modern ECMO technology where lower levels of anticoagulation are able to maintain circuit patency while minimizing bleeding risk.