Improved results treating lung allograft failure with venovenous extracorporeal membrane oxygenation

Primary graft dysfunction following lung transplantation: From pathogenesis to future frontiers

Lung transplantation is the treatment of choice for patients with end-stage lung disease. Currently, just under 5000 lung transplants are performed worldwide annually. However, a major scourge leading to 90-d and 1-year mortality remains primary graft dysfunction. It is a spectrum of lung injury ranging from mild to severe depending on the level of hypoxaemia and lung injury post-transplant. This review aims to provide an in-depth analysis of the epidemiology, pathophysiology, risk factors, outcomes, and future frontiers involved in mitigating primary graft dysfunction. The current diagnostic criteria are examined alongside changes from the previous definition. We also highlight the issues surrounding chronic lung allograft dysfunction and identify the novel therapies available for ex-vivo lung perfusion. Although primary graft dysfunction remains a significant contributor to 90-d and 1-year mortality, ongoing research and development abreast with current technological advancements have shed some light on the issue in pursuit of future diagnostic and therapeutic tools.

Outcomes of Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Lung Transplantation

BACKGROUND

Primary graft dysfunction (PGD) is the leading cause of death in the first 30 days after lung transplantation and is also associated with worse long-term outcomes. Outcomes of patients with PGD grade 3 requiring extracorporeal membrane oxygenation (ECMO) support after lung transplantation have yet to be well described. We sought to describe short- and long-term outcomes for patients with PGD grade 3 who required ECMO support.

METHODS

This is a single-center retrospective cohort study of patients undergoing lung transplantation. We stratified patients with PGD grade 3 into non-ECMO, venoarterial (VA) ECMO, and venovenous (VV) ECMO groups after transplantation. We then compared the outcomes between the groups.

RESULTS

Of 773 lung transplant recipients, PGD grade 3 developed in 204 (26%) at any time in the first 72 hours after lung transplantation. Of these, 13 (5%) required VA ECMO and 25 (10%) required VV ECMO support. The 30-day, 1-year, and 5-year survival in the VA ECMO group was 62%, 54%, and 43% compared with 96%, 84%, and 65% in the VV ECMO group and 99%, 94%, and 71% in the non-ECMO group. Multivariable Cox regression analysis showed that VA ECMO was associated with increased mortality (hazard ratio, 2.37; 95% CI, 1.06-5.28; P = .04).

CONCLUSIONS

Patients who required VA ECMO support for PGD grade 3 have significantly worse survival compared with those who did not require ECMO and those who required VV ECMO support. This suggests that VA ECMO treatment of patients with PGD grade 3 after lung transplantation can be a predictable risk factor for mortality.

The American Association for Thoracic Surgery (AATS) 2022 Expert Consensus Document: The use of mechanical circulatory support in lung transplantation

OBJECTIVE

The use of mechanical circulatory support (MCS) in lung transplantation has been steadily increasing over the prior decade, with evolving strategies for incorporating support in the preoperative, intraoperative, and postoperative settings. There is significant practice variability in the use of these techniques, however, and relatively limited data to help establish institutional protocols. The objective of the AATS Clinical Practice Standards Committee (CPSC) expert panel was to review the existing literature and establish recommendations about the use of MCS before, during, and after lung transplantation.

METHODS

The AATS CPSC assembled an expert panel of 16 lung transplantation physicians who developed a consensus document of recommendations. The panel was broken into subgroups focused on preoperative, intraoperative, and postoperative support, and each subgroup performed a focused literature review. These subgroups formulated recommendation statements for each subtopic, which were evaluated by the entire group. The statements were then developed via discussion among the panel and refined until consensus was achieved on each statement.

RESULTS

The expert panel achieved consensus on 36 recommendations for how and when to use MCS in lung transplantation. These recommendations included the use of veno-venous extracorporeal membrane oxygenation (ECMO) as a bridging strategy in the preoperative setting, a preference for central veno-arterial ECMO over traditional cardiopulmonary bypass during the transplantation procedure, and the benefit of supporting selected patients with MCS postoperatively.

CONCLUSIONS

Achieving optimal results in lung transplantation requires the use of a wide range of strategies. MCS provides an important mechanism for helping these critically ill patients through the peritransplantation period. Despite the complex nature of the decision making process in the treatment of these patients, the expert panel was able to achieve consensus on 36 recommendations. These recommendations should provide guidance for professionals involved in the care of end-stage lung disease patients considered for transplantation.

Extracorporeal life support as a bridge to pulmonary retransplantation: prognostic factors for survival in a multicentre cohort analysis

OBJECTIVES

Pulmonary retransplant (ReTx) is considered a controversial procedure. Despite literature reporting outcomes following ReTx, limited data exist in recipients bridged to their ReTx on extracorporeal life support (ECLS). The goal of this study was to investigate the outcomes of recipients bridged to a first-time ReTx by ECLS.

METHODS

We performed a retrospective multicentre cohort analysis from 10 centres in Europe, Asia and North America. The primary outcome was overall survival. Risk factors were analysed using Cox regression models.

RESULTS

ECLS as a bridge to a first-time ReTx was performed in 50 recipients (ECLS-ReTx). During the study period, 210 recipients underwent a first-time ReTx without bridging on ECLS (regular-ReTx) and 4959 recipients had a primary pulmonary transplant (index-Tx). The overall 1-year (55%) and 5-year (29%) survival was significantly worse for the ECLS-ReTx group.Compared to the index-Tx group, the mortality risk was significantly higher after ECLS-ReTx [hazard ratio 2.76 (95% confidence interval 1.94-3.91); P < 0.001] and regular-ReTx [hazard ratio 1.65 (95% confidence interval 1.36-2); P < 0.001].In multivariable analysis, recipient age ≥35 years, time interval <1 year from index-Tx, primary graft dysfunction as transplant indication, venoarterial-extracorporeal membrane oxygenation and Zurich donor score ≥4 points were significant risk factors for mortality in ECLS-ReTx recipients.

CONCLUSIONS

Recipients for ECLS-ReTx should be carefully selected. Risk factors, such as recipient age, intertransplant interval, primary graft dysfunction as transplant indication and type of ECLS should be kept in mind before bridging these patients on ECLS to ReTx.

Postoperative Management of Lung Transplant Recipients in the Intensive Care Unit

The number of lung transplantations is progressively increasing worldwide, providing new challenges to interprofessional teams and the intensive care units. The outcome of lung transplantation recipients is critically affected by a complex interplay of particular pathophysiologic conditions and risk factors, knowledge of which is fundamental to appropriately manage these patients during the early postoperative course. As high-grade evidence-based guidelines are not available, the authors aimed to provide an updated review of the postoperative management of lung transplantation recipients in the intensive care unit, which addresses six main areas: (1) management of mechanical ventilation, (2) fluid and hemodynamic management, (3) immunosuppressive therapies, (4) prevention and management of neurologic complications, (5) antimicrobial therapy, and (6) management of nutritional support and abdominal complications. The integrated care provided by a dedicated multidisciplinary team is key to optimize the complex postoperative management of lung transplantation recipients in the intensive care unit.

Early postoperative complications in lung transplant recipients

Lung transplantation has become an established therapy for end-stage lung diseases. Early postoperative complications can impact immediate, mid-term, and long-term outcomes. Appropriate management, prevention, and early detection of these early postoperative complications can improve the overall transplant course. In this review, we highlight the incidence, detection, and management of these early postoperative complications in lung transplant recipients.

Extracorporeal membrane oxygenation and lung transplantation

The use of extracorporeal membrane oxygenation has had a positive impact on the outcomes after lung transplantation. Extracorporeal membrane oxygenation has a role in all phases of lung transplantation-preoperative, intraoperative, and postoperative periods. It serves as a bridge to transplantation in appropriate patients awaiting lung transplantation. Extracorporeal membrane oxygenation is used as a preferred method of cardiopulmonary support in some centres during implantation; and, after lung transplantation, it can be used to salvage the implanted lung in cases of severe primary graft dysfunction or as a planned extension of intraoperative extracorporeal membrane oxygenation onto the postoperative period. It has now gained acceptance as a mandatory tool in most lung transplant units. This article reviews the history of extracorporeal membrane oxygenation and lung transplantation, their subsequent development, and the current use of extracorporeal membrane oxygenation during lung transplantation. Our institutional practice and experience are described. The implications of the current global coronavirus disease pandemic on extracorporeal membrane oxygenation and lung transplantation are also briefly discussed.

Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Lung Transplantation

Extracorporeal membrane oxygenation (ECMO) is used as the last resort for primary graft dysfunction (PGD). The aim of this study is to explore the predictors and outcomes for early mortality in postlung transplant patients who required ECMO for PGD. Between January 2006 and December 2015, 1,049 cases of lung transplantation were performed at our center. Ninety-six patients required ECMO support after lung transplantation, 52 patients (54%) had PGD. Seven patients (13.5%) required venoarterial ECMO due to concomitant hemodynamical instability, and the others required venovenous ECMO. The patients were on ECMO for 5.00 ± 10.6 days. Forty-four patients (84.6%) were successfully decannulated. The 90 day, 1 year, and 5 year survival of patients who required ECMO for PGD after lung transplantation were 67.3%, 50.0%, and 31.5%, respectively. Cox regression indicated that when the patient was placed on ECMO later than 48 hours after transplantation, the patient could have higher in-house mortality (hazard ratio, 2.79; 95% CI, 1.21-6.43) and also higher 3 year mortality (hazard ratio, 2.30; 95% CI, 1.13-4.68) regardless of the patients' preoperative conditions or complexity of lung transplantation. Earlier recognition of PGD and initiation of ECMO may be beneficial in this population.

Lung transplantation for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis. Lung transplantation is the only intervention shown to increase life expectancy for patients with IPF, but it is associated with disease-specific challenges. In this Review, we discuss the importance of a proactive approach to the management of IPF comorbidities, including gastro-oesophageal reflux, pulmonary hypertension, coronary artery disease, and malignancy. With a donor pool too small to meet demand and unacceptably high mortality on transplant waiting lists, we discuss different systems used internationally to facilitate organ allocation. We explore the rapidly evolving landscape of transplantation for patients with IPF with regards to antifibrotic therapy, technological advances in extracorporeal life support, advances in understanding of the genetics of the disease, and the importance of a holistic multidisciplinary approach to care. Finally, we consider potential advances over the next decade that are envisaged to improve transplantation outcomes in patients with advanced IPF.

The Role and Impact of Extracorporeal Membrane Oxygenation in Critical Care

Use of extracorporeal membrane oxygenation (ECMO) has been exponentially increasing over the last decade and is now considered a mainstream lifesaving treatment modality in critical care medicine. However, the need for physician education, training, and experience remains imperative. Although ECMO has traditionally been used in end-stage lung disease and circulatory collapse, it is being adopted for use in right heart failure, as a bridge to heart and lung transplantation, and as rescue therapy for both sepsis and post-organ transplantation. The following article discusses indications, management, complications, and challenges of ECMO as well as our experience at the Houston Methodist DeBakey Heart & Vascular Center.

Extracorporeal support, during and after lung transplantation: the history of an idea

During recent years, continuous technological innovation has provoked an increase of extracorporeal life support (ECLS) use for perioperative cardiopulmonary support in lung transplantation. Initial results were disappointing, due to ECLS-specific complications and high surgical risk of the supported patients. However, the combination of improved patient management, multidisciplinary team work and standardization of ECLS protocols has recently yielded excellent results in several case series from high-volume transplant centres. Therein, it was demonstrated that, although the prevalence of complications remains higher in supported patients, there may be no difference in long-term graft function between supported and non-supported patients. These results are important, because most of the patients who require ECLS support in lung transplantation are young and have no other chance to survive, but to be transplanted. Moreover, there is no device for "bridging to destination" therapy in lung transplantation. Of note, the evidence in favour of ECLS support in lung transplantation was never validated by randomized controlled trials, but by everyday experience at the patient bed-side. Here, we review the state-of-the-art ECLS evidence for intraoperative and postoperative cardiopulmonary support in lung transplantation.

Extracorporeal Life Support as a Bridge to Lung Transplantation in Patients With Acute Respiratory Failure

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is being used more often as a bridge to transplantation (BTT) in patients with acutely decompensated end-stage lung disease in Korea. ECMO as a BTT may be the only rescue strategy for severe acute respiratory failure, but many centers still consider it to be a relative contraindication to lung transplantation because of its poor outcome. Because there are not enough lung donors, it is important to determine their optimal use. We reviewed and analyzed our experiences with the use of ECMO as a BTT in patients with acute respiratory failure.

METHODS

This was a retrospective analysis of all patients with acutely decompensated end-stage lung disease treated with ECMO as a bridge to lung transplantation between March 2012 and February 2016.

RESULTS

Of the 194 patients who underwent respiratory ECMO over a 4-year period, a BTT strategy was used for 19 patients (median age, 58 years) on our institution's lung transplantation waiting list (15 veno-venous, 3 veno-veno-arterial, 1 veno-arterial). Fourteen patients (73.7%) were successfully bridged to transplantation; however, 3 died while on the waiting list and 2 returned to their baseline functions without transplantation. The overall in-hospital survival rate was 57.9% (11 of 19), including the 9 (64.3%) patients who underwent transplantation.

CONCLUSIONS

Our findings support the view that well-selected candidates with acutely decompensated end-stage lung disease may be safely bridged until a suitable donor is identified. ECMO is not able to reverse the course of patients; however, it could be a life-saving option for patients with acute respiratory failure requiring lung transplantation.

Risk Factor Analysis for Intraoperative Extracorporeal Membrane Oxygenation Weaning Failure After Lung Transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been widely used for hemodynamic support during lung transplantation (LTx). We evaluated the risk factors associated with failure of weaning from ECMO in the operating room during LTx.

METHODS

We retrospectively reviewed 74 consecutive patients who had undergone LTx from March 2013 to February 2016. Patients who underwent single LTx, multiorgan transplantation, and LTx for pulmonary hypertension were excluded. All operations were performed under ECMO support. Clinical data of donor, recipient, and intraoperative parameters were reviewed.

RESULTS

Younger donors (40 ± 11 versus 45 ± 10 years, p = 0.047), donors with shorter mechanical ventilation (125 ± 74 versus 160 ± 80 minutes, p = 0.066) and donors with higher Pao₂ at 100% oxygen (455 ± 87 mm Hg versus 399 ± 88 mm Hg, p = 0.008) were significantly different in the ECMO weaning group than in the weaning failure group. Of the recipients, the number of patients who had preoperative ECMO support were significantly fewer in the successful weaning group than in the weaning failure group (11.9% versus 34.4%, p = 0.061). The operation time was significantly shorter in the weaning group than in the weaning failure group (392 ± 66 versus 435 ± 82 minutes, p = 0.014). In multivariate logistic regression analysis, the independent risk factors for ECMO weaning were donor age (odds ratio 1.101, 95% confidence interval: 1.030 to 1.177, p = 0.005), donor Pao₂ (odds ratio 0.992, 95% confidence interval: 0.984 to 0.999, p = 0.034), and operation time (odds ratio 1.010, 95% confidence interval: 1.000 to 1.019, p = 0.043).

CONCLUSIONS

Our results showed that younger donor age, high Pao₂, and shorter operation time were factors related to successful ECMO weaning in the operating room after LTx.

Extracorporeal membrane oxygenation following lung transplantation: indications and survival

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is employed to rescue patients with early graft dysfunction after lung transplantation (LTx). Rates of post-LTx ECMO and subsequent outcomes have been limited to single-center reports.

METHODS

UNOS registry was queried for LTx recipients from March 2015 to March 2016; 2,001 recipients were identified and stratified by need for post-LTx ECMO. Logistic regression was used to determine variables associated with post-LTx ECMO. Cox proportional hazards modeling identified factors associated with survival. Kaplan-Meier analysis with log-rank testing was employed for survival analysis.

RESULTS

Of 2,001 recipients identified, 107 required post-LTx ECMO (5.1%). Recipients requiring ECMO were younger (56 vs 60 years, p = 0.007) and had higher body mass index (27.2 vs 25.8, p = 0.012). Recipients requiring post-LTx ECMO were more likely to have required mechanical ventilation before transplant (9.3% vs 4.9%, p = 0.049) and were more likely to have required pre-transplant ECMO (15% vs 3.7%, p < 0.001). On multivariable analysis, pre-transplant ECMO and increasing ischemic time were associated with post-LTx ECMO. Six-month survival for recipients requiring ECMO was 62.2%. On multivariable analysis, need for post-transplant dialysis was associated with mortality. Six-month survival for recipients requiring ECMO with and without dialysis was 25.8% and 86.7% (p < 0.001).

CONCLUSIONS

In a nationally representative database, ischemic time and pre-transplant ECMO and/or ventilator requirement were associated with need for post-LTx ECMO. Need for post-transplant dialysis was associated with mortality in patients requiring post-LTx ECMO. These data may permit improved prediction of graft dysfunction. Strategies to minimize renal toxicity in the perioperative phase may lead to improved early survival post-LTx.

The potential of accurate SVO2 monitoring during venovenous extracorporeal membrane oxygenation: an in vitro model using ultrasound dilution

Introduction. Some degree of recirculation occurs during venovenous extracorporeal membrane oxygenation (VV ECMO) which, (1) reduces oxygen (O2) delivery, and (2) renders venous line oxygen saturation monitoring unreliable as an index of perfusion adequacy. Ultrasound dilution allows clinicians to rapidly monitor and quantify the percent of recirculation that is occurring during VV ECMO. The purpose of this paper is to test whether accurate patient mixed venous oxygen saturation (SVO2) can be calculated once recirculation is determined. It is hypothesized that it is possible to derive patient mixed venous saturations by integrating recirculation data with the ECMO circuit arterial and venous line oxygen saturation data. Methods. A test system containing sheep blood adjusted to three venous saturations (low-30%, med-60%, high-80%) was interfaced via a mixing chamber with a standard VV ECMO circuit. Recirculation, arterial line and venous line oxygen saturations were measured and entered into a derived equation to calculate the mixed venous saturation. The resulting value was compared to the actual mixed venous saturation. Results. Recirculation was held constant at 30.5 ± 2.0% for all tests. A linear regression comparison of “actual” versus “calculated” mixed venous saturations produced a correlation coefficient of R2 = 0.88. Direct comparison of actual versus calculated saturations for all three test groups respectively are as follows; Low: 31.8 ± 3.95% vs. 37.0 ± 6.7% (NS), Med: 61.7 ± 1.5% vs. 72.3 ± 1.8% (p < 0.05), High: 84.4 ± 0.9% vs. 91.2 ± 1.1% (p < 0.05). Discussion. There was a strong correlation between actual and calculated mixed venous saturations; however, significant differences between actual and calculated values where observed at the Med and High groups. While this data suggests that using quantified recirculation data to calculate SVO2 is promising, it appears that a straightforward derivative of the oxygen saturation-based equation may not be sufficient to produce clinically accurate calculations of actual mixed venous saturations. Perfusion (2007) 22, 239—244.

Lung transplantation at Duke

Lung transplantation represents the gold-standard therapy for patients with end-stage lung disease. Utilization of this therapy continues to rise. The Lung Transplant Program at Duke University Medical Center was established in 1992, and since that time has grown to one of the highest volume centers in the world. The program to date has performed over 1,600 lung transplants. This report represents an up-to-date review of the practice and management strategies employed for safe and effective lung transplantation at our center. Specific attention is paid to the evaluation of candidacy for lung transplantation, donor selection, surgical approach, and postoperative management. These evidence-based strategies form the foundation of the clinical transplantation program at Duke.

Effects of Additional Intra-aortic Balloon Counter-Pulsation Therapy to Cardiogenic Shock Patients Supported by Extra-corporeal Membranous Oxygenation

Extra-corporeal membranous oxygenation (ECMO) has been applied in patients with cardiopulmonary failure. One critical drawback of peripheral ECMO is an increase in left ventricular (LV) afterload which could be counterbalanced by the combination of intra-aortic balloon counter-pulsation (IABP) therapy. We hypothesized that an add-on therapy with IABP could improve outcomes in patients receiving ECMO support. We included patients (>18 years old) from 2002 to 2013 requiring ECMO support due to cardiogenic shock in a medical center. A total of 529 patients (227 ECMO alone and 302 combined IABP plus ECMO) were included. The mortality rates at 2 weeks (48.5 vs. 47.7%) after ECMO implantation were not different between the two groups (ECMO vs. combined group). After adjustment for propensity score and potential confounders, the odds ratios of outcomes within 14 days (combined group vs. ECMO) for poor LV systolic function, high preload, multi-organ failure and mortality were not different. The results remained similar for subgroup analysis. Compared with ECMO alone, combined IABP and ECMO treatment did not improve outcomes in patients with circulatory failure.

Successfully treated severe obstetric sepsis and acute respiratory distress syndrome with extracorporeal membrane oxygenation

We report a unique clinical case about an 18-year-old woman, immediately post-partum after an urgent C-section, who survived severe sepsis, acute respiratory distress syndrome (ARDS) and disseminated intravascular coagulation (DIC) and was successfully treated with 11 different antibiotics, massive blood transfusions and repetitive surgeries and was on extracorporeal membrane oxygenation (ECMO) support for 22 days. Although, ECMO is a time-limited procedure and most manufacturers do not advise more than 14 days of use, the situation for this patient was life-threatening and ECMO, despite the dangerous risks listed above, was the only way to win time for the lungs to recover and for treatment of the underlying disease, while maintaining adequate oxygenation and circulation. Fortunately, the condition of this woman was stabilized and she achieved complete physical recovery, despite minor neurological deficit in the fingers of her right hand.

Mechanical circulatory support in lung transplantation: Cardiopulmonary bypass, extracorporeal life support, and ex-vivo lung perfusion

Lung transplant is the standard of care for patients with end-stage lung disease refractory to medical management. There is currently a critical organ shortage for lung transplantation with only 17% of offered organs being transplanted. Of those patients receiving a lung transplant, up to 25% will develop primary graft dysfunction, which is associated with an 8-fold increase in 30-d mortality. There are numerous mechanical lung assistance modalities that may be employed to help combat these challenges. We will discuss the use of mechanical lung assistance during lung transplantation, as a bridge to transplant, as a treatment for primary graft dysfunction, and finally as a means to remodel and evaluate organs deemed unsuitable for transplant, thus increasing the donor pool, improving survival to transplant, and improving overall patient survival.

Extracorporeal removal CO2 using a venovenous, low-flow system (Decapsmart) in a lung transplanted patient: a case report

BACKGROUND

Primary graft dysfunction (PGD) is a syndrome that may occur after lung transplantation. In some cases of severe PGD, conventional therapies like ventilatory support, administration of inhaled nitric oxide (iNO), and surfactant and intravenous prostacyclins are inadequate to achieve adequate gas exchange. The only lifesaving option is to use an extracorporeal membrane oxygenator. The Decapsmart is a new venovenous, low-flow extracorporeal device to removal carbon dioxide (CO(2)). It does not need a specialized staff. Herein we have presented a case report of a patient who underwent single lung transplantation and experienced respiratory failure.

METHODS

On November 2007, a 52-year-old woman underwent a single right lung transplantation, and developed severe PGD in the postoperative period. After institution of conventional treatments, including ventilatory and hemodynamic support, iNO, and prostaglandine E1, we started treatment with Decapsmart to remove CO(2). Hemodynamic and respiratory parameters were assessed at baseline and after 3, 12, 24, and 48 hours.

RESULTS

No adverse events occurred. From baseline to 48 hours, pH values increased and partial pressure of CO(2) reduced. At the same time ventilatory support was reduced, thereby mitigating barotrauma and risk of overdistension.

CONCLUSION

The use of Decapsmart may be an important aid for patients with severe respiratory acidosis in association with conventional therapy during the perioperative period after lung transplantation.

Bridge to lung transplantation and rescue post-transplant: the expanding role of extracorporeal membrane oxygenation

Over the last several decades, the growth of lung transplantation has been hindered by a much higher demand for donor lungs than can be supplied, leading to considerable waiting time and mortality among patients waiting for transplant. This has led to the search for an alternative bridging strategy in patients with end-stage lung disease. The use of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation as well as a rescue strategy post-transplant for primary graft dysfunction (PGD) has been studied previously, however due to initially poor outcomes, its use was not heavily instituted. In recent years, with significant improvement in technologies, several single and multi-center studies have shown promising outcomes related to the use of ECMO as a bridging strategy as well as a therapy for patients suffering from PGD post-transplant. These results have challenged our current notion on ECMO use and hence forced us to reexamine the utility, efficacy and safety of ECMO in conjunction with lung transplantation. Through this review, we will address the various aspects related to ECMO use as a bridge to lung transplantation as well as a rescue post-transplant in the treatment of PGD. We will emphasize newer technologies related to ECMO use, examine recent observational studies and randomized trials of ECMO use before and after lung transplantation, and reflect upon our own institutional experience with the use of ECMO in these difficult clinical situations.

Low-flow venovenous CO₂ removal in association with lung protective ventilation strategy in patients who develop severe progressive respiratory acidosis after lung transplantation

BACKGROUND

Primary graft dysfunction (PGD) might occur after lung transplantation. In some severe cases, conventional therapies like ventilatory support, administration of inhaled nitric oxide (iNO), and intravenous prostacyclins are not sufficient to provide an adequate gas exchange. The aim of our study was to evaluate the use of a lung protective ventilation strategy associated with a low-flow venovenous CO2 removal treatment to reduce ventilator-associated injury in patients that develop severe PGD after lung transplantation.

METHODS

From January 2009 to January 2011, 3 patients developed PGD within 24 hours after lung transplantation. In addition to conventional medical treatment, including hemodynamic support, iNO and prostaglandin E1 (PGE1), we initiated a ventilatory protective strategy associated with low-flow venovenous CO2 removal treatment (LFVVECCO2R). Hemodynamic and respiratory parameters were assessed at baseline as well as after 3, 12, 24, and 48 hours.

RESULTS

No adverse events were registered. Despite decreased baseline elevated pulmonary positive pressures, application of a protective ventilation strategy with LFVVECCO2R reduced PaCO2 and pulmonary infiltrates as well as increased pH values and PaO2/FiO2 ratios. Every patient showed simultaneous improvement of clinical and hemodynamic conditions. They were weaned from mechanical ventilation and extubated after 24 hours after the use of the low-flow venovenous CO2 removal device.

CONCLUSION

The use of LFVVECCO2R together with a protective lung ventilation strategy during the perioperative period of lung transplantation may be a valid clinical strategy for patients with PGD and severe respiratory acidosis occured despite adequate mechanical ventilation.

Clinical neurology in lung transplantation

Lung transplantation is the only established therapeutic option for several end-stage respiratory diseases. Limited mostly by lack of suitable allografts, the results have measurably improved over the last decade. Numerous surgical and pharmaceutical improvements have had positive impact on outcomes. The potential for critical care issues and the need for interdisciplinary management remains paramount. Cardiac, renal, and metabolic complications are frequently encountered in the acute postoperative phase. Allograft rejection and infectious diseases as well as problems related to immunosuppressive regimen are seen later after lung transplantation. Neurologic manifestations with a range of etiologies are discussed here in this context.

Anesthetic management including extracorporeal membrane oxygenation therapy of liver transplant recipient with life-threatening hypoxemia -a case report-

We present a rare case of successful anesthetic management for a patient who had refractory hypoxia during liver transplantation (LT) with intraoperative veno-venous (VV) extracorporeal membrane oxygenation (ECMO) support. A 49 year-old female patient underwent living donor LT. After reperfusion of the grafted liver, graft congestion and massive oozing developed. Thus it was decided to reoperate with a temporary gauze packing. However, the patient's condition deteriorated with azotemia and severe hypoxemia. VV ECMO with continuous renal replacement therapy was started 24 hours before secondary LT and maintained during secondary LT. VV ECMO was weaned 32 hours after secondary LT. This case indicates that not only after the LT but also before and during LT, VV ECMO can be a treatment option for the patient with end-stage liver disease combined with respiratory failure when there is the possibility of lung recovery.

Primary graft dysfunction

Primary graft dysfunction (PGD) is a syndrome encompassing a spectrum of mild to severe lung injury that occurs within the first 72 hours after lung transplantation. PGD is characterized by pulmonary edema with diffuse alveolar damage that manifests clinically as progressive hypoxemia with radiographic pulmonary infiltrates. In recent years, new knowledge has been generated on risks and mechanisms of PGD. Following ischemia and reperfusion, inflammatory and immunological injury-repair responses appear to be key controlling mechanisms. In addition, PGD has a significant impact on short- and long-term outcomes; therefore, the choice of donor organ is impacted by this potential adverse consequence. Improved methods of reducing PGD risk and efforts to safely expand the pool are being developed. Ex vivo lung perfusion is a strategy that may improve risk assessment and become a promising platform to implement treatment interventions to prevent PGD. This review details recent updates in the epidemiology, pathophysiology, molecular and genetic biomarkers, and state-of-the-art technical developments affecting PGD.

[Extracorporeal membrane oxygenation in primary graft dysfunction in a paediatric double lung transplant: presentation of a case]

Primary graft dysfunction is a leading cause of morbimortality in the immediate postoperative period of patients undergoing lung transplantation. Among the treatment options are: lung protective ventilatory strategies, nitric oxide, lung surfactant therapy, and supportive treatment with extracorporeal membrane oxygenation (ECMO) as a bridge to recovery of lung function or re-transplant. We report the case of a 9-year-old girl affected by cystic fibrosis who underwent double-lung transplantation complicated with a severe primary graft dysfunction in the immediate postoperative period and refractory to standard therapies. Due to development of multiple organ failure, it was decided to insert arteriovenous ECMO catheters (pulmonary artery-right atrium). The postoperative course was satisfactory, allowing withdrawal of ECMO on the 5th post-surgical day. Currently the patient survives free of rejection and with an excellent quality of life after 600 days of follow up.

Pediatric extracorporeal life support in specialized situations

OBJECTIVES

The purpose of this review was to provide a systematic review of the literature regarding the use of extracorporeal life support (ECLS) in various specialized conditions, as part of the Pediatric Cardiac Intensive Care Society/Extracorporeal Life Support Organization Joint Statement on Mechanical Circulatory Support.

DATA SOURCES

MEDLINE and PubMed.

STUDY SELECTION

Searches for published abstracts and articles were conducted using the following MeSH terms: extracorporeal life support, extracorporeal membrane oxygenation, or mechanical support, and pediatric or children.

DATA EXTRACTION

Abstracts of all articles including case reports were reviewed; the full article was reviewed if the abstract indicated that it focused on extracorporeal life support for conditions other than primary respiratory disease or persistent pulmonary hypertension of the newborn and described outcomes such as survival to hospital discharge. Studies with potential overlapping patients were highlighted in the review process and summary results.

DATA SYNTHESIS

Classification of recommendations and level of evidence are expressed in the American College of Cardiology Foundation/American Heart Association format.

CONCLUSIONS

The majority of specialized situations where extracorporeal life support is used fall into the category of class II-III evidence. Class I indications for extracorporeal life support in the pediatric population include myocarditis and in the context of acute interventions in the cardiac catheterization laboratory.

Outcome of extracorporeal membrane oxygenation as a bridge to lung transplantation and graft recovery

BACKGROUND

Indications for extracorporeal membrane oxygenation (ECMO) use in lung transplantation are (1) temporary assistance as a bridge to transplantation, (2) stabilization of hemodynamics during transplantation in place of cardiopulmonary bypass, and (3) treatment of severe lung dysfunction and primary graft failure after transplantation. This study compares the survival of lung transplant recipients requiring ECMO support with survival of patients without ECMO.

METHODS

A retrospective database review was performed for 108 consecutive patients who underwent single-lung or bilateral-lung transplantation at our center between 2002 and 2009.

RESULTS

Of 108 transplant recipients, 27 (25%) required venoarterial ECMO compared with 81 patients who did not. Nine patients required ECMO preoperatively (87±102 hours), and ECMO was continued for 5 patients during the lung transplant operation. Seven additional patients received ECMO during transplantation. Six patients required early (<7 days) and 5 patients delayed (≥7 days) postoperative ECMO for treatment of allograft dysfunction. The subgroup with support showed the most favorable patient discharge rate (66.7%). ECMO support was a significant risk factor for death (p<0.001). Survival was significantly reduced with the use of ECMO: 30-day, 90-day, 1-year, and 5-year survival was 97%, 91%, 83%, and 58% in the patients without ECMO compared with 63%, 44%, 33%, and 21% in those with ECMO, respectively.

CONCLUSIONS

Survival after lung transplantation was significantly reduced with ECMO. However, patients who survived the first year showed similar long-term survival as those patients who did not need perioperative ECMO support.

[ECMO in lung transplantation]

New technologies have become available to minimize the adverse events of extracorporeal devices. Link to these technological improvements ECMO in lung transplantation is currently essential. Bridging to lung transplantation changes to concepts avoiding the sequels mechanical ventilation and thereby offers improvement of lung recipients prior to the transplant procedure. Its use as hemodynamic and respiratory support during the lung transplant surgery can replace conventional Cardiopulmonary bypass. And finally, ECMO is sometimes the only alternative in the most severe forms of primary graft failure.

Successful lung retransplantation after extended use of extracorporeal membrane oxygenation as a bridge

Redo lung transplantation remains a major clinical challenge and its indication for patients with early allograft dysfunction is difficult to determine. We report a case of potentially fatal early allograft dysfunction owing to possible acute cellular rejection after single lung transplantation in a patient who underwent redo double lung transplantation after successful use of extracorporeal membrane oxygenation as a bridge, which resulted in a successful outcome.

Improved survival but marginal allograft function in patients treated with extracorporeal membrane oxygenation after lung transplantation

BACKGROUND

Previous reports demonstrate that 1-year survival is severely compromised in patients with severe primary graft dysfunction (PGD) after lung transplantation. We examined if advances in extracorporeal membrane oxygenation (ECMO) support, including polymethylpentene oxygenators and reliance on venovenous (VV) ECMO have improved outcomes in patients with severe PGD after lung transplantation.

METHODS

The analysis included data prospectively collected on all single-lung or double-lung transplants between November 2001 and December 2009. Heart-lung transplants were excluded. Comparisons were made between recipients who did and did not require ECMO for PGD after transplant.

RESULTS

Since November 2001, when VV ECMO became the routine treatment for severe PGD after transplant at our center, 28 of 498 patients (6%) have required VV ECMO support. Successful weaning occurred in 27 of 28 (96%). Support was withdrawn for 1 patient with irreversible neurologic injury. Survival was substantially better than in previous reports: 30 days, 82%; 1 year, 64%; and 5 years, 49%. Freedom from bronchiolitis obliterans syndrome was 88% in the ECMO survivors at 3 years, but maximum allograft function was considerably worse than in transplant recipients not requiring ECMO (peak forced expiratory volume in 1 second: 58% in ECMO vs 83% in non-ECMO, p=0.001).

CONCLUSIONS

Advances in ECMO technology, particularly VV ECMO, have greatly improved the ability to support patients with severe PGD after lung transplantation. VV ECMO is an important tool in the armamentarium of any lung transplant program to optimize patient outcomes; however, strategies to improve lung allograft function in patients experiencing severe PGD are still needed.

Extracorporeal membrane oxygenation as a bridge to lung transplant: midterm outcomes

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is used occasionally as a bridge to lung transplantation. The impact on mid-term survival is unknown. We analyzed outcomes after lung transplant over a 19-year period in patients who received ECMO support.

METHODS

From March 1991 to October 2010, 1,305 lung transplants were performed at our institution. Seventeen patients (1.3%) were supported with ECMO before lung transplant. Diagnoses included retransplantation (n = 6), pulmonary fibrosis (n = 6), cystic fibrosis (n = 4), and chronic obstructive pulmonary disease (n = 1). Fifteen patients underwent double lung transplant, one patient had single left lung transplant and one patient had a heart-lung transplant. Venovenous and venoarterial ECMO were implanted in eight and nine cases, respectively. Median duration of support was 3.2 days (range, 1 to 49 days). Mean patient follow-up was 2.3 years.

RESULTS

Thirty-day, 1-year, and 3-year survivals were 81%, 74%, and 65%, respectively, for the supported patients and 93%, 78%, and 62% in the control group (p = 0.56). Two-year survival was not affected by ECMO type, with survival of five out of nine patients supported by venoarterial ECMO vs seven out of eight patients supported by venovenous ECMO (p = 0.17). At 1- year follow-up, allograft function for the ECMO-supported patients did not differ from the control group (forced expiratory volume in one second, 2.35 L vs 2.09 L, p = 0.39) (forced vital capacity, 3.06 L vs 2.71 L, p = 0.34).

CONCLUSIONS

Extracorporeal membrane oxygenation as a bridge to lung transplantation is associated with higher perioperative mortality but acceptable mid-term survival in carefully selected patients. Late allograft function did not differ in patients who received ECMO support before lung transplant from those who did not receive ECMO.

Extracorporeal life support as a bridge to lung transplantation

Patients who are excellent candidates for lung transplantation often die on the waiting list because they are too sick to survive until an organ becomes available. Improvements in lung transplant outcomes, patient selection, and artificial lung device technologies have made it possible to bridge these patients to successful life-saving transplantation. Extracorporeal life support (ECLS) should be tailored to minimize morbidity and provide the appropriate mode and level of cardiopulmonary support for each patient's physiologic requirements. Novel device refinements and further development of ECLS in an ambulatory and simplified manner will help maintain these patients in better condition until transplantation.