Long-term Extracorporeal Membrane Oxygenation Support Research Articles

PULM9: Development of a Novel Cannula for Durable Venovenous Extracorporeal Membrane Oxygenation

Background: Fifteen million Americans suffer from chronic obstructive pulmonary disease (COPD). After failed optimal medical therapy, the only definitive treatment is lung transplantation, which is limited due to donor scarcity. Extracorporeal membrane oxygenation (ECMO) can be used in acute exacerbations of COPD or as a bridge to transplant for waitlisted COPD patients, but it is not currently suited for long-term respiratory support. Existing venovenous (VV) ECMO configurations often utilize a dual lumen cannula that is inserted into the jugular vein and is designed for short term use. While effective, dual lumen cannulas are associated with high resistance and malposition which limits blood flow, promotes cavitation, and increases blood trauma. Furthermore, patient ambulation is cumbersome because of the difficulty of securing the dual lumen cannula safely to the patient. A novel ECMO system that provides durable respiratory support could reduce morbidity and mortality in patients and facilitate ambulatory use. To this end, a dual lumen cannula that is attached to the heart and tunneled to a more ergonomic position could provide more durable, long term ECMO support. Here, we describe our initial efforts to develop a durable VV ECMO cannula with reduced resistance. Methods: A novel cannula for long-term VV ECMO support was developed using computer aided design. The cannula is designed for surgical attachment to the right atrium with the cannula’s drainage tip at the cavoatrial junction and the reinfusion port directed towards the tricuspid valve to minimize recirculation. Pressure drop was evaluated for the novel cannula, 28Fr, and 32Fr Crescent cannulas (MC3, Dexter, MI) for comparison (N≥5) in circuits primed with deionized water at ambient temperature. A Rotaflow (Maquet, Wayne, NJ) blood pump was operated at 2700-3625 RPM, and pressure drop was assessed for flow rates between 0.1 – 5 LPM. Porcine hearts were harvested from healthy pigs and utilized for ex vivo cannula fit studies. Water flow through the cannula into the right atrium was evaluated using videography. Results: The novel cannula drainage pressure drop (-12±1.1mmHg) was similar to the 28Fr Crescent (-13± 0.3mmHg) and 32Fr Crescent (-9±0.3mmHg) at 2LPM (Figure 1). Reinfusion pressure drop was similar between the novel cannula (22±1.2mmHg) and the 32Fr Crescent (21±0.4mmHg), and higher for the 28Fr Crescent (43±0.9mmHg) at 2LPM. Total pressure drop was similar between the novel cannula (33.4±1.2mmHg) and 32Fr Crescent (29.4±0.5mmHg) and higher for the 28Fr Crescent (57±1.0mmHg) at 2LPM. In ex-vivo heart studies flow through the novel cannula was directed towards the tricuspid valve and entered the right ventricle. Conclusions: Our novel cannula possesses an excellent pressure-flow profile, comparable to the largest-bore commercially available dual lumen cannulas. This novel cannula will enhance durability and ease of use for patients requiring durable mechanical respiratory support.Figure 1. Pressure Flow Curve for Novel VV ECMO Cannula

PULM14: Long-haul ECMO as Bridge to Transplant in COVID-19 ARDS

Background: Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (LT) is an established treatment modality for refractory acute respiratory distress syndrome (ARDS). Per the Scientific Registry of Transplant Recipients (SRTR) database, 215 patients supported on ECMO due to the Coronavirus disease of 2019 (COVID-19) related ARDS underwent LT between August 2020 and June 2022. The COVID-19 pandemic limited donor availability and increased duration of ECMO support in ECMO-dependent patients listed for LT. Outcomes of long-term ECMO as bridge to transplant (BTT) in this population remain unclear, and no cases of VV ECMO greater than 200 days has been documented in the literature. Methods: A single-center review was conducted to identify patients cannulated for VV-ECMO to treat COVID-19 associated ARDS between January 1, 2021 and January 1, 2022. Patients were selected who were supported by VV-ECMO for ARDS secondary to COVID-19 for greater than 200 days before receiving a lung transplant. Detailed analysis was performed for the outcomes and characteristics of all patients who received a lung transplant for post-COVID-19 ARDS after >200 days of VV-ECMO support. Results: Three patients were identified as long-term ECMO as BTT recipients (>200 days) for COVID-19-associated ARDS. Average age was 38 years (22,52), BMI 32.9 (31.6,34) and no patients had any known relevant respiratory medical history. One patient had a history of daily e-cigarette use. All patients were unvaccinated at the time of first positive COVID-19 test. All were successfully bridged to bilateral lung transplant (BLT) off of VV-ECMO. None required VV-ECMO post-operatively. One patient required VA-ECMO post-operatively for elevated pulmonary arterial pressures related to incidentally discovered septal defects. Average ECMO duration was 278 days (250, 324). Two patients were cannulated as bridge to recovery, and one as bridge to decision. Patients remained ambulant on ECMO support until they were able to undergo the transplant procedure. Cannulation strategies included double lumen right internal jugular (RIJ), RIJ to right femoral vein, and bifemoral venous cannulation. Complications on ECMO included sepsis, hemorrhage, stroke, reconfiguration, and atrial fibrillation. Two were discharged to home and one to inpatient rehabilitation. Average length of stay after transplant was 27 days (16,37). All 3 patients have continued to do well. Conclusion: We present three patients with the longest documented VV-ECMO support for COVID-19 ARDS a bridge to lung transplant. Our findings suggest long-term VV-ECMO support is a feasible bridge to LT for patients with COVID-19-related ARDS when used in the long-term (>200 days). The duration of ECMO support remains associated with known ECMO-related complications. Post-transplant survival to-date suggests that survival in long-term ECMO support as a BTT may be comparable to short-term ECMO in patients with COVID-19-related ARDS.

Directed Hypercapnia for Weaning From ECMO to Mechanical Ventilation—Progress or Just a Process?

In this issue of The Annals of Thoracic Surgery, Kluis and colleagues1Kluis A. Shih E. Squiers J.J. et al.Directed hypercapnia as a strategy to wean extracorporeal membrane oxygenation in COVID-19 pneumonia.Ann Thorac Surg. 2022; 114: e307-e309Abstract Full Text Full Text PDF Scopus (1) Google Scholar report a single-institution experience with 5 cases of severe COVID-19 acute respiratory distress syndrome (ARDS) with hypercarbic respiratory failure using directed hypercapnia as a strategy to wean patients from venovenous extracorporeal membrane oxygenation (ECMO). The authors instituted a directed hypercapnia approach in combination with metabolically compensated respiratory acidosis to terminate long-term ECMO support and to reduce associated morbidity and mortality. Five patients were successfully weaned off ECMO. One patient with preexisting kidney disease requiring renal replacement therapy ultimately died of refractory acidosis and sepsis. ECMO duration ranged from 56 to 167 days, highlighting the extended duration of support. More than 13,000 cases of COVID-19 requiring ECMO have been reported to the Extracorporeal Life Support Organization registry with a 47% in-hospital mortality.2Extracorporeal Life Support OrganizationELSO live registry dashboard of ECMO patient data.https://www.elso.org/Registry/ELSOLiveRegistryDashboard.aspxDate accessed: March 20, 2022Google Scholar Early use of ECMO for COVID-19 resulted in poor outcomes, with many clinicians discouraging this application.3Henry B.M. Lippi G. Poor survival with extracorporeal membrane oxygenation in acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19): pooled analysis of early reports.J Crit Care. 2020; 58: 27-28Crossref PubMed Scopus (144) Google Scholar As the pandemic progressed, ECMO use increased rapidly, and more recent data suggest similar outcomes to non-COVID ARDS.4Barbaro R.P. MacLaren G. Boonstra P.S. et al.Extracorporeal membrane oxygenation support in COVID-19: an international cohort study of the Extracorporeal Life Support Organization registry.Lancet. 2020; 396: 1071-1078Abstract Full Text Full Text PDF PubMed Scopus (420) Google Scholar Much of the management of ECMO and mechanical ventilation has been extrapolated from non-COVID ARDS populations. Whereas most centers use lung-protective ventilation, there are no standard guidelines for ventilator management in this setting. Institutional demands and experiences often dictate the pathway of care. The authors report an ECMO weaning protocol that successfully liberated patients from this high-risk, resource-intensive therapy, allowing discharge from a tertiary center to long-term acute rehabilitation facilities. At the individual patient level, this may translate into decreases in the morbidity and mortality associated with prolonged ECMO. At the health system level, the economic and resource allocation benefits associated with freeing up intensive care beds, staff, and resources could be immense. This protocol could be particularly valuable during high infectivity periods when the health system is significantly strained. Certain considerations temper enthusiasm for widespread adoption of this protocol. Individualized care is essential, and recovery is the primary aim. As reported, all survivors remain on assist-control ventilation, and long-term outcomes, including prospects for eventual ventilator liberation, are unknown. Patients may have been better served with sedative reduction, extubation, and ambulation on ECMO. In addition, proponents of directed hypercapnia must ensure that protocols do not restrict evaluation for lung transplantation. Outcomes from ECMO bridging to transplantation have improved because of better patient selection and protocolized management approaches. As highlighted in a recent US nationwide analysis published in the New England Journal of Medicine, lung transplantation is an important option for refractory COVID-19 ARDS or post-COVID fibrosis, with promising early outcomes including 95% 3-month survival in more than 200 recipients.5Roach A. Chikwe J. Catarino P. et al.Lung transplantation for Covid-19–related respiratory failure in the United States.N Engl J Med. 2022; 386: 1187-1188Crossref PubMed Scopus (24) Google Scholar Notwithstanding, there will likely be a role for directed hypercapnia in this population, which will be further delineated as more research is performed. Directed Hypercapnia as a Strategy to Wean Extracorporeal Membrane Oxygenation in COVID-19 PneumoniaThe Annals of Thoracic SurgeryVol. 114Issue 5PreviewCoronavirus disease 2019 pneumonia with respiratory failure refractory to maximum medical therapy has been successfully managed with venovenous extracorporeal membrane oxygenation. This report describes a process of using directed hypercapnia in 5 patients to wean them from prolonged extracorporeal support secondary to refractory hypercarbic respiratory failure. Full-Text PDF

Development of an ambulatory extracorporeal membrane oxygenation system: From concept to clinical use

Extracorporeal membrane oxygenation (ECMO) is a modality of life support for patients suffering from respiratory and/or cardiac failure. With the advances in membrane oxygenation and pump technology in the last two decades, ECMO has become safer and more durable for clinical use. Along with its overall use, there has been an increase in patients who require long-term ECMO support; either awaiting lung recovery or transplantation. Many of them are awake, participating in physical rehabilitation, and even ambulating while supported on ECMO. While the broader ECMO experience is applied to bed-restricted and mechanically ventilated patients, contemporary studies demonstrated that the artificial respiration provided by ECMO is compatible with freedom from adjunctive mechanical ventilation, ambulation, and exercise. With this in mind, our group set out to develop a novel ambulatory ECMO system to facilitate ambulation in patients supported on ECMO. This paper gives a brief overview of the development of this system, focusing on the journey from a laboratory concept to approval for clinical use by the Food and Drug Administration.

Catastrophic Mechanical Complications of Extracorporeal Membrane Oxygenation.

Technical advances in extracorporeal membrane oxygenation (ECMO) have increased the number of cases that maintain longer duration. Long-term use of ECMO results in ECMO-related complications. Anticipation of the life-threatening mechanical complications and their management are critical for safe ECMO. In this study, we analyzed the incidence, nature, and risk factors of life-threatening mechanical complications during ECMO support. Furthermore, we presented our bedside algorithms to manage catastrophic ECMO complications. Data from 549 patients who underwent ECMO between December 2008 and December 2018 were retrospectively analyzed. The incidence of all life-threatening mechanical complications was 4.0%. Accidental decannulation (1.3%) was most common, followed by abrupt falling circuit flows (1.1%), pump failure (1.1%), circuit rupture (0.4%), and air in circuit (0.2%). Most (90.9%) of life-threatening events required circuit and cannula change, while 9.1% required vein collapse relief procedure. There was no death related to the event; however, six (27.3%) died during ECMO due to the underlying disease for which ECMO was required, and three (13.6%) died after weaning from ECMO. Multivariate regression analysis showed that awake ECMO and long-term ECMO support were significantly associated with life-threatening mechanical complications (p < 0.01). Our algorithm safely managed catastrophic ECMO problems without event-related deaths.

Long-term Respiratory Extracorporeal Membrane Oxygenation and Prognosis: A Retrospective Analysis.

The duration of extracorporeal membrane oxygenation (ECMO) treatments increases, however, data presented from prolonged support is limited. We retrospectively analyzed all patients during a 4-year period undergoing respiratory ECMO for duration of therapy, demographics, therapy-associated parameters, and outcome according to ECMO duration (<28 days and ≥28 days = long-term ECMO). Out of 55 patients undergoing ECMO for ARDS or during bridging to lung transplantation, 18 were on ECMO for ≥28 days (33%). In the long-term group, median ECMO run time was 40 days (interquartile range 34-54 days). Hospital survival was not significantly different between the groups (54% in short-term and 50% in long-term ECMO patients). There was a significantly higher proportion of patients suffering from malignancy in the group of long-term nonsurvivors. Recovery occurred after more than 40 days on ECMO in 3 patients. The longest ECMO run time in a hospital survivor was 65 days. Duration of ECMO support alone was no prognostic factor and should not represent a basis for decision-making. In patients suffering from malignancy, long-term ECMO support seems to be a factor of adverse prognosis, if not futile.

Long-Term Venovenous Extracorporeal Membrane Oxygenation Support for Acute Respiratory Distress Syndrome

Given substantial advances in venovenous extracorporeal membrane oxygenation (ECMO) technology, long-term support is increasingly feasible. Although the benefits of short-term ECMO as a bridge to recovery in acute respiratory distress syndrome (ARDS) are well described, the utility and outcomes of long-term support remain unclear. Patients requiring ECMO for ARDS between January 2009 and November 2012 were retrospectively reviewed and analyzed separately for those requiring ECMO support for less than 3 weeks or for 3 weeks or longer. Demographic factors, ECMO variables, and outcomes were assessed. Fifty-five patients with ARDS received ECMO during the study period, with 11 patients requiring long-term ECMO support and a median duration of 36 (interquartile range: 24 to 68) days. Recovery was the initial goal in all patients. Pre-ECMO mechanical ventilatory support, indices of disease severity, and the ECMO cannulation strategy were similar between the two groups. Eight (73%) patients receiving long-term support were bridged to recovery, and 1 patient was bridged to transplantation after a refractory course. Eight (73%) patients receiving long-term support and 25 (57%) patients receiving short-term support survived to 30 days and hospital discharge. Previously, long-term ECMO support was thought to be associated with unfavorable outcomes. This study, however, may provide support for the efficacy of ECMO support even for 3 weeks or more as a bridge to recovery or transplantation.

Outcomes of Long-Term Veno-Venous Extracorporeal Membrane Oxygenation Support for Acute Respiratory Distress Syndrome

Purpose Given substantial advances in veno-venous extracorporeal membrane oxygenation (ECMO) technology, long-term support is increasingly feasible. Although the benefits of short-term ECMO as a bridge to recovery in acute respiratory distress syndrome (ARDS) are well described in the literature, the outcomes of patients requiring long-term support remain unclear. Methods and Materials Patients requiring ECMO for ARDS between January 2009 and November 2012 were retrospectively reviewed and analyzed separately for those requiring short-term and long-term ECMO support (≥3 weeks). Demographics, ECMO variables and outcomes of patient bridged to recovery or transplantation were assessed. Results 57 patients with ARDS were placed on ECMO during that time period with 11 patients requiring long-term ECMO support (59±51 days). Recovery was the goal in all patients. In the long-term support group, pre-ECMO mechanical ventilation was conventional PC or PRVC (N=4), APRV (N=5), or HFO (N=2). The mean pre-ECMO FiO2 was 0.93±0.13 with mean pH, PaO2, and PaCO2 of 7.3±0.1, 69±26 mmHg, 63±21 mmHg, respectively. Pre-ECMO Murray Scores were 3.7±0.4 and 3.82±0.29 (p=NS) in the long-term and short-term groups, respectively. 8 (73%) long-term support patients were successfully bridged to recovery and 1 patient was bridged to transplantation after a refractory course. 25 (52%) short-term support patients and 8 (73%) long-term support patients survived to 30-days or hospital discharge. In the long-term support group, 4 of the 8 surviving patients had mid-term follow-up available; with 100% surviving, returned to home, and with normal functional status at 1 year. Conclusions Previously, long-term ECMO support has not been thought to be associated with favorable outcomes. This study, however, may provide support for the efficacy of ECMO for patients even requiring support greater than 3 weeks as a bridge to recovery or transplantation.

The Impact of Extracorporeal Membrane Oxygenation on Survival in Pediatric Patients With Respiratory and Heart Failure: Review of Our Experience

Extracorporeal membrane oxygenation (ECMO) is widely used for circulatory support in pediatric cardiac patients with low cardiac output and hypoxemia. We retrospectively evaluated the efficacy of ECMO support for respiratory and heart failure in infants and children. From April 2002 to February 2011, 14 patients aged 19 days to 20 years old (average 44 months), with body weight 2.6 kg to 71 kg (median 14.1 kg), underwent ECMO support for failing cardiac function, hypoxemia, and low cardiac output syndrome. In 12 patients, ECMO was introduced after operation for congenital heart disease (four with complete repair including Fontan circulation, and eight with palliative repair). In one patient, ECMO was introduced after partial pulmonary resection for congenital cystic adenomatoid malformation because of respiratory failure. ECMO was introduced in a patient with severe heart failure caused by fulminant myocarditis. Patients' demographics, duration of extracorporeal membrane oxygenation, additional support, and outcomes were analyzed. Ten patients (71%) were successfully weaned from ECMO, and eight patients (57%) were discharged from the hospital. The mean duration of ECMO support was 332 h (range 11-2030 h). Although management of the ECMO circuit, including anticoagulation (activated clotting time: 150-250), was conducted following the institutional practice guidelines, it was difficult to control the bleeding. Seven patients required renal replacement therapy during ECMO support using peritoneal dialysis or continuous hemodiafiltration. Five patients had additional operative procedures: systemic-pulmonary shunt in two, bidirectional Glenn takedown with right modified Blalock-Taussig shunt, total cavopulmonary connection takedown, and redo ECMO in one patient each. The patient who had the longest ECMO support for respiratory failure due to acute respiratory distress syndrome after lung surgery was successfully weaned from ECMO because high-frequency oscillation (HFO) improved respiratory function. ECMO for heart and respiratory failure in infants and children is effective and allows time for recovery of cardiac dysfunction and acute hypoxic insult. The long-term ECMO support for over 2000 h was very rare, but it was possible to wean this patient from ECMO using HFO.

How to ensure a good flow to the arm during direct axillary artery cannulation

We herein describe a simple and safe technique to avoid compartment syndrome/arm ischemia during direct right axillary artery cannulation, especially in patients who require long-term extracorporeal membrane oxygenation support.

Extracorporeal Membrane Oxygenator Support in a Case of Severe Status Asthmaticus

Support with extracorporeal membrane oxygenation (ECMO) can sustain life for a substantial period of time, but the role of long-term ECMO support is limited. The National Institutes of Health ECMO collaborative study revealed no significant reduction in mortality in adults with severe respiratory distress syndrome treated with ECMO. The value of ECMO in the treatment of transient, severe acute respiratory insufficiency has been demonstrated in patients after cardiac operations, in patients with Pneumocystis carinii pneumonia, and in patients following trauma. We present an example of refractory respiratory failure in a young asthmatic with massive atelectasis in whom the institution of ECMO allowed us to perform adequate pulmonary lavage. It resulted in improvement in gas exchange and the patient's survival.