Extracorporeal membrane oxygenation support before lung transplant: A bridge over troubled water

Impact of Preoperative Extracorporeal Membrane Oxygenation Use on Lung Transplant Outcomes

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) may be used to support critically ill patients before lung transplantation. The relationship between preoperative venoarterial and venovenous ECMO and their relationship with lung transplantation indications remain poorly elucidated.

METHODS

This study analyzed data from the Organ Procurement and Transplantation Network database pertaining to adult lung transplant recipients who underwent transplantation procedures between January 1, 2018, and December 20, 2023. Patients were categorized by preoperative ECMO status. Multivariable risk adjustment was performed with Cox mixed-effect models and logistic regression. Subgroup analysis was performed on patients who underwent lung transplantation for coronavirus disease 2019 (COVID-19) and restrictive lung disease.

RESULTS

Of 12,098 lung transplant recipients, 854 (7%) required ECMO preoperatively. Patients who underwent preoperative ECMO were younger (median age, 52 years vs 63 years; P < .001), were more likely not to have diabetes (81.0% vs 74.5%; P < .001) and had different primary diagnoses compared with other lung transplant recipients. After risk adjustment, preoperative venovenous ECMO use was not associated with a shorter time to graft failure or lower survival (P = .864 and P = .140, respectively). However, preoperative venoarterial ECMO was associated with lower survival (hazard ratio [HR], 1.36; P = .014) and higher need for ECMO 72 hours after transplantation (odds ratio, 3.83; P < .001). In subgroup analysis, patients with restrictive lung disease who required venoarterial ECMO before lung transplantation had inferior survival compared to those with VV-ECMO and no ECMO (P = .010 and P = .023, respectively). Patients who underwent lung transplantation for COVID-19 had similar survival regardless of their preoperative venovenous ECMO status (HR, 0.943; P = .522).

CONCLUSIONS

Preoperative venoarterial ECMO is associated with worse overall survival in lung transplant recipients, but venovenous ECMO is not. These findings are consistent across disease origin and transplantation indication.

Extracorporeal membrane oxygenation for prevention of barotrauma in patients with respiratory failure: A scoping review

BACKGROUND

Barotrauma is a frequent complication in patients with severe respiratory failure and is associated with poor outcomes. Extracorporeal membrane oxygenation (ECMO) implantation allows to introduce lung-protective ventilation strategies that limit barotrauma development or progression, but available data are scarce. We performed a scoping review to summarize current knowledge on this therapeutic approach.

METHODS

We systematically searched PubMed/MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for studies investigating ECMO as a strategy to prevent/limit barotrauma progression in patients with respiratory failure. Pediatric studies, studies on perioperative implantation of ECMO, and studies not reporting original data were excluded. The primary outcome was the rate of barotrauma development/progression.

RESULTS

We identified 21 manuscripts presenting data on a total of 45 ECMO patients. All patients underwent veno-venous ECMO. Of these, 21 (46.7%) received ECMO before invasive mechanical ventilation. In most cases, ECMO implantation allowed to modify the respiratory support strategy (e.g., introduction of ultraprotective/low pressure ventilation in 12 patients, extubation while on ECMO in one case, and avoidance of invasive ventilation in 15 cases). Barotrauma development/progression occurred in <10% of patients. Overall mortality was 8/45 (17.8%).

CONCLUSION

ECMO implantation to prevent barotrauma development/progression is a feasible strategy and may be a promising support option.

Cannulation Configuration and Its Effects on Bridging to Lung Transplant: Analysis of the Extracorporeal Life Support Organization Registry

BACKGROUND

Donor stagnation and modification of lung allocation scores has resulted in a higher acuity of patient presentation before lung transplantation. Extracorporeal membrane oxygenation (ECMO) has been used as a bridge to lung transplant (BTT), although the effect of cannulation strategy on outcomes has not been well investigated. We analyzed contemporary data on ECMO BTT by using a large, international registry of patients.

METHODS

We used the Extracorporeal Life Support Organization registry to identify all adult patients from 2010 to 2022 undergoing ECMO as a BTT. Patients were stratified by venovenous or venoarterial support type.

RESULTS

A total of 1066 patients were identified. ECMO BTT increased over the study period (P < .001), as did survival to hospital discharge (P < .001), with an overall survival of 87.7%. Venovenous patients experienced fewer complications on ECMO, including dialysis (16.7% vs 25.3%, P = .006), stroke (1.4% vs 5.1%, P = .004), and limb ischemia (0.2% vs 3.4%, P < .001) and required ECMO less frequently in the postoperative period (41.0% vs 53.4%, P = .002) and for less time (4 days [interquartile range, 2-7 days] vs 5 days [interquartile range, 3-9 days], P = .01). In-hospital mortality was significantly lower for venovenous patients compared with venoarterial patients (11.0% vs 18.5%, P = .005). Increasing center volume of ECMO BTT was protective of in-hospital mortality (P < .001), with benefit observed after ∼45 total BTT intent cannulations.

CONCLUSIONS

ECMO BTT has resulted in improved posttransplant survival to discharge. Owing to a higher rate of complications and worsened mortality, thoughtful implementation of venoarterial ECMO in BTT should be undertaken when assessing patient candidacy.

Venopulmonary extracorporeal membrane oxygenation for right ventricular support as a bridge to lung transplantation: A narrative review

This review evaluates the effectiveness of veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation as a bridge to lung transplantation strategy in patients undergoing veno-venous extracorporeal membrane oxygenation while awaiting lung transplantation. Examining indications, contraindications, and clinical outcomes, the study highlights potential benefits, drawing insights from successful cases in South Korea and the United States. Despite limited sample sizes, veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation emerges as a promising approach for further investigation in lung transplantation support. The review emphasizes its role in improving hemodynamic status, preventing complications during extended waiting periods, and presenting a cost-effective alternative to traditional methods, especially in developing countries. While in-hospital mortality rates range from 0% to 10%, comparable to other approaches, cautious optimism surrounds veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation, urging expanded research to solidify its standing in enhancing patient outcomes, reducing costs, and promoting transplant success.

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.

Donor Lung Preservation at 10°C: Clinical and Logistical Impact

INTRODUCTION

Cold static donor lung preservation at 10°C appears to be a promising method to safely extend the cold ischemic time (CIT) and improve lung transplant (LTx) logistics.

METHODS

LTx from November 2021 to February 2023 were included in this single institution, prospective, non-randomized study comparing prolonged preservation at 10°C versus standard preservation on ice. The inclusion criteria for 10°C preservation were suitable grafts for LTx without any donor retrieval concerns.

PRIMARY ENDPOINT

primary graft dysfunction (PGD) grade-3 at 72-h. Secondary endpoints: clinical outcomes, cytokine profile and logistical impact.

RESULTS

Thirty-three out of fifty-seven cases were preserved at 10°C. Donor and recipient characteristics were similar across the groups. Total preservation times (h:min) were longer (p<0.001) in the 10°C group [1st lung: median 12:09 (IQR 9:23-13:29); 2nd: 14:24 (12:00-16:20)] vs. standard group [1st lung: median 5:47 (IQR 5:18-6:40); 2nd: 7:15 (6:33-7:40)]. PGD grade-3 at 72-h was 9.4% in 10°C group vs. 12.5% in standard group (p=0.440). Length of mechanical ventilation (MV), ICU and hospital stays were similar in both groups. Thirty and ninety-day mortality rates were 0% in 10°C group (vs. 4.2% in standard group). IL-8 concentration was significantly higher 6-h post-LTx in the standard group (p=0.025) and IL-10 concentration was increased 72-h post-LTx in the 10°C group (p=0.045).

CONCLUSIONS

Preservation at 10°C may represent a safe and feasible strategy to intentionally prolong the CIT. In our center, extending the CIT at 10°C may allow for semi-elective LTx and improve logistics with similar outcomes compared to the current standard preservation on ice.

Lobar Lung Transplantation: A Single-Center 10-Year Experience

BACKGROUND

The shortage of donors for lung transplants is the main limitation of the preceding. Lobar transplantation is an alternative especially useful in patients with short stature and small thoracic cavities. The aim of this study was to perform a descriptive analysis of Portuguese patients who underwent lobar lung transplantation.

METHODS

A retrospective study was conducted, and patients submitted to lobar lung transplantation from January 2012 to December 2023 were evaluated. A descriptive analysis was made, including demographic data, lung diseases, waiting list dynamics, pre-transplant evaluations, and post-transplant outcomes.

RESULTS

Sixteen lobar transplants were performed with a predominance of female patients and a median age of 47 years. Most patients had interstitial lung disease or bronchiectasis either due to cystic fibrosis or non-cystic fibrosis. The median predicted total lung capacity (pTLC) ratio was 0.73. The median waiting list time was 6 months with 9 urgent transplants and 1 emergent lobar retransplant. Extracorporeal membrane oxygenation (ECMO) was used in pre-, intra-, and postoperative periods. Most transplanted lobes were the median lobe (ML) + right upper lobe (RUL) and left upper lobe (LUL). The median length of stay was 58 days, with complications such as PDG grade 3, bronchial tree ischemia, and concentrical stenosis of bronchial anastomosis. Six patients died in this period, 1 in the immediate postoperative period and 5 during the post-transplant hospitalization, with a median survival of 20.7 months and a 1-year and 5-year survival rate of 60%.

CONCLUSION

Our results show a population with an increased waiting list converging in many urgent cases, with an early mortality and high primary graft dysfunction rate. Nevertheless, mid- and long-term survival are promising.

Nurses' Interventions in Minimizing Adult Patient Vulnerability During Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplantation: An Integrative Review

Introduction

People during extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation find themselves in a high degree of physical and psychological vulnerability, which could cause additional problems for their health status. Therefore, this review aims to identify the interventions that shape critical nursing care to minimize patient vulnerability during ECMO as a bridge to lung transplantation.

Method

A literature review was performed using CINAHL, MEDLINE, PubMed, Scopus and Web of Science databases with searches conducted in March 2023, with temporal restriction of articles published between 2013 and 2023. After selecting articles involving adults in critical situations on ECMO, their quality was assessed using the critical appraisal tools from the Joanna Briggs Institute. Articles with the pediatric population, reviews, and opinion articles were excluded. A spreadsheet was built for data extraction and a narrative analysis was performed.

Results

Three articles were included involving 40 participants in total. Interventions that shape critical nursing care to minimize a person's vulnerability are in the physical domain (basic precautions to prevent infection) and in the psychological domain (trusting relationships, consistent and clear communication, physical presence of nurses and family members and the use of advocacy). The Awake ECMO strategy was identified as beneficial for reducing vulnerability.

Conclusion

By recognizing and identifying the person's vulnerability during ECMO as a bridge to lung transplantation, nurses can implement effective interventions to minimize vulnerability in this population, thus contributing to the person's well-being through personalization and individualization of care. Additionally, the results of this review could be useful for developing tools to assess the degree of vulnerability and for implementing person-centered care measures and policies. However, further research is warranted given the scarcity of literature on these topics.

Recovery of Lung Function After 149 Days on Extracorporeal Membrane Oxygenation for COVID-19

This report highlights survival and the patient's perspective after prolonged venovenous extracorporeal membrane oxygenation (ECMO) for COVID-19-related respiratory failure. A 36-year-old man with COVID-19 presented with fever, anosmia, and hypoxia. After respiratory deterioration necessitating intubation and lung-protective ventilation, he was referred for ECMO. After 3 days of conventional venovenous ECMO, he required multiple creative cannulation configurations. Adequate sedation and recurrent bradycardia were persistent challenges. After 149 consecutive days of ECMO, he recovered native lung function and was weaned from mechanical ventilation. This represents the longest-duration ECMO support in a survivor of COVID-19 yet reported. Necessary strategies included unconventional cannulation and flexible anticoagulation.

Extracorporeal Membrane Oxygenation in Acute Respiratory Failure

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a form of mechanical life support that provides full respiratory bypass in patients with severe respiratory failure as a bridge to recovery or lung transplantation. The use of ECMO for respiratory failure and capable centers offering ECMO has expanded over the years, increasing its availability. As VV-ECMO provides an artificial mechanism for oxygenation and decarboxylation of native blood, it allows for an environment in which safer mechanical ventilatory care may be provided, allowing for treatment and resolution of underlying respiratory pathologies. Landmark clinical trials have provided a framework for better understanding patient selection criteria, resource utilization, and outcomes associated with ECMO when applied in settings of refractory respiratory failure. Maintaining close vigilance and management of complications during ECMO as well as identifying strategies post-ECMO (e.g., recovery, transplantation, etc.), are critical to successful ECMO support. In this review, we examine considerations for candidate selection for VV-ECMO, review the evidence of utilizing VV-ECMO in respiratory failure, and provide practical considerations for managing respiratory ECMO patients, including complication identification and management, as well as assessing for the ability to separate from ECMO support and the procedures for decannulation.