Extracorporeal membrane oxygenation with spontaneous breathing as a bridge to lung transplantation

Hemocompatibility Evaluation of a Novel Ambulatory Pulmonary Assist System Using a Lightweight Axial-Flow Pump

The Pulmonary Assist System (PAS) is currently under development as a wearable respiratory assist system. In this study, the hemocompatibility of the PAS's axial-flow mechanical pump (AFP) was compared to other contemporary mechanical pumps in an acute ovine model. The PAS was attached to a normal sheep in a venovenous configuration using one of three pumps: 1) AFP, 2) ReliantHeart HeartAssist 5 (control), or 3) Abbott Pedimag (control) (n = 5 each). Each sheep was supported on the PAS for 12 hours with two L/minute of blood flow and four L/minute of sweep gas. Hemolysis, coagulation, inflammation, and platelet activation and loss were compared among the groups. In this study, the plasma-free hemoglobin (pfHb) was less than 10 mg/dl in all groups. The pfHb was significantly lower in the AFP group compared to other groups. There was no significant clot formation in the pumps and oxygenators in all groups. Furthermore, no significant differences in coagulation (oxygenator resistance, fibrinopeptide A), inflammation (white blood cell counts, IL-8), and platelet activation and loss (p-selectin, platelet counts) were observed among the groups (all, p > 0.05). This study demonstrates equivalent hemocompatibility of the PAS's AFP to other contemporary mechanical pumps with a reduced level of hemolysis on startup.

Mechanical ventilation during extracorporeal membrane oxygenation support - New trends and continuing challenges

BACKGROUND

The impact of mechanical ventilation on the survival of patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) due to severe acute respiratory distress syndrome (ARDS) remains still a focus of research.

METHODS

Recent guidelines, randomized trials, and registry data underscore the importance of lung-protective ventilation during respiratory and cardiac support on ECMO.

RESULTS

This approach includes decreasing mechanical power delivery by reducing tidal volume and driving pressure as much as possible, using low or very low respiratory rate, and a personalized approach to positive-end expiratory pressure (PEEP) setting. Notably, the use of ECMO in awake and spontaneously breathing patients is increasing, especially as a bridging strategy to lung transplantation. During respiratory support in V-V ECMO, native lung function is of highest importance and adjustments of blood flow on ECMO, or ventilator settings significantly impact the gas exchange. These interactions are more complex in veno-arterial (V-A) ECMO configuration and cardiac support. The fraction on delivered oxygen in the sweep gas and sweep gas flow rate, blood flow per minute, and oxygenator efficiency have an impact on gas exchange on device side. On the patient side, native cardiac output, native lung function, carbon dioxide production (VCO2), and oxygen consumption (VO2) play a role. Avoiding pulmonary oedema includes left ventricle (LV) distension monitoring and prevention, pulse pressure >10 mm Hg and aortic valve opening assessment, higher PEEP adjustment, use of vasodilators, ECMO flow adjustment according to the ejection fraction, moderate use of inotropes, diuretics, or venting strategies as indicated and according to local expertise and resources.

CONCLUSION

Understanding the physiological principles of gas exchange during cardiac support on femoro-femoral V-A ECMO configuration and the interactions with native gas exchange and haemodynamics are essential for the safe applications of these techniques in clinical practice. Proning during ECMO remains to be discussed until further data is available from prospective, randomized trials implementing individualized PEEP titration during proning.

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.

Standardized approach for extubation during extracorporeal membrane oxygenation in severe acute respiratory distress syndrome: a prospective observational study

BACKGROUND

Extubation during extracorporeal oxygenation (ECMO) in severe acute respiratory distress syndrome (ARDS) has not been well studied. Despite the potential benefits of this strategy, weaning from ECMO before liberation from invasive mechanical ventilation remains the most frequent approach. Our aim was to evaluate the safety and feasibility of a standardized approach for extubation during ECMO in patients with severe ARDS.

RESULTS

We conducted a prospective observational study to assess the safety and feasibility of a standardized approach for extubation during ECMO in severe ARDS among 254 adult patients across 4 intensive care units (ICU) from 2 tertiary ECMO centers over 6 years. This consisted of a daily assessment of clinical and gas exchange criteria based on an Extracorporeal Life Support Organization guideline, with extubation during ECMO after validation by a dedicated intensive care medicine specialist. Fifty-four (21%) patients were extubated during ECMO, 167 (66%) did not reach the clinical criteria, and in 33 (13%) patients, gas exchange precluded extubation during ECMO. At ECMO initiation, there were fewer extrapulmonary organ dysfunctions (lower SOFA score [OR, 0.88; 95% CI, 0.79-0.98; P = .02] with similar PaO2/FiO2) when compared with patients not extubated during ECMO. Extubation during ECMO associated with shorter duration of invasive mechanical ventilation (7 (4-18) vs. 32 (18-54) days; P < .01) and of ECMO (12 (7-25) vs. 19 (10-41) days; P = .01). This was accompanied by a lower incidence of hemorrhagic shock (2 vs. 11%; P = .05), but more cannula-associated deep vein thrombosis (49 vs. 31%; P = .02) and failed extubation (20 vs. 6%; P < .01). There were no increased major adverse events. Extubation during ECMO is associated with a lower risk of all-cause death, independently of measured confounding (adjusted logistic regression OR 0.23; 95% confidence interval 0.08-0.69, P = .008).

CONCLUSIONS

A standardized approach was safe and feasible allowing extubation during ECMO in 21% of patients with severe ARDS, selecting patients who will have a shorter duration of invasive mechanical ventilation, ECMO course, and ICU stay, as well as fewer infectious complications, and high hospital survival.

Fundamentals of weaning veno-arterial and veno-venous extracorporeal membrane oxygenation

Recent advances in veno-arterial (VA) and veno-venous (VV) extracorporeal membrane oxygenation (ECMO) technology and management have enabled us to support patients with cardiac and/or pulmonary failure, who may have previously been considered untreatable. VA ECMO and VV ECMO are by definition transient therapies and serve as a bridge to recovery, bridge to decision, bridge to transplant, or bridge to no recovery. Weaning ECMO should be considered for all patients once native cardiac and pulmonary function show signs of recovery. Currently, there are no universally accepted protocols for weaning VA and VV ECMO, and consequently, each individual center follows their own weaning protocols. The aim of this review article is to describe different approaches to safely wean from VA and VV ECMO.

Analgosedation in Critically Ill Adults Receiving Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation (ECMO) is an increasingly utilized intervention for cardiopulmonary failure. Analgosedation during ECMO support is essential to ensure adequate pain and agitation control and ventilator synchrony, optimize ECMO support, facilitate patient assessment, and minimize adverse events. Although the principles of analgosedation are likely similar for all critically ill patients, ECMO circuitry alters medication pharmacodynamics and pharmacokinetics. The lack of clinical guidelines for analgosedation during ECMO, especially at times of medication shortage, can affect patient management. Here, we review pharmacological considerations, protocols, and special considerations for analgosedation in critically ill adults receiving ECMO support.

Major Bleeding and Thromboembolic Events in Veno-Venous Extracorporeal Membrane Oxygenation-Patients With Isolated Respiratory Failure

Bleeding and thromboembolic events are common during veno-venous extracorporeal membrane oxygenation (vvECMO). It is unknown whether these complications are driven by the ECMO system itself, multiorgan-failure, or both. The aim of this study was to assess the prevalence of bleeding and thromboembolic events in patients with isolated respiratory failure. Patients with vvECMO were retrospectively included from March 2009 to October 2017. Exclusion included any organ failure other than respiratory. Major bleeding was defined as a decrease in hemoglobin ≥2 g/dl per 24 hours, the requirement for transfusion of ≥2 packed red blood cell concentrates per 24 hours, any retroperitoneal, pulmonary, central nervous system bleeding, or bleeding requiring surgery. Thromboembolic events were assessed by duplex sonography or CT scan. Of 601 patients, 123 patients with a mean age of 49 ± 15 years and a median Sepsis-related Organ Failure Assessment score of 8 (7-9) were eligible for the analysis. Major bleeding was observed in 73%; 35% of all bleedings occurred on the day of or after ECMO initiation. A more pronounced decrease of PaCO2 after ECMO initiation was seen in patients with intracranial bleeding (ICB) compared with those without. Thromboembolic events were noted in 30%. The levels of activated prothrombin time, fibrinogen, platelet count, or D-dimers affected neither bleeding nor the prevalence of thromboembolic events.

Heparin-Free Lung Transplantation on Venovenous Extracorporeal Membrane Oxygenation Bridge

Extracorporeal membrane oxygenation (ECMO) bridge to lung transplantation (LuTX) exposes the patients to a high risk of perioperative bleeding secondary to systemic anticoagulation and coagulation factors deficiency. With this case series, we propose innovative "no-heparin" management of ECMO-bridge support during LuTX, based upon 1) control heparin resistance with antithrombin III in the preoperative period; 2) relying upon a fully functional, brand new heparinized ECMO circuit; 3) completely avoiding perioperative heparin; 4) hampering fibrinolysis with tranexamic acid; and 5) limiting venoarterial (VA) ECMO escalation, and the following need for full anticoagulation. Following the application of this new approach, we carried out three challenging clinical cases of bilateral ECMO-bridged LuTX effectively, with limited intraoperative blood requirement and no major postoperative bleeding or thromboembolic events. Of note, two of them had an extremely high risk for hemorrhage due to complete right lung anatomic derangement in case number 2 and surgical adhesion following first LuTX in case number 3, while for the case number 1, no blood products were administered during surgery. Despite the limited patient population, such an approach relies on a strong rationale and may be beneficial for managing ECMO bridging to LuTX. Prospective studies are necessary to confirm the validity of our strategy.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary technology capable of supporting cardiac and respiratory function in the presence of end-stage lung disease. Initial experiences using ECMO as a bridge to lung transplant (ECMO-BTLT) were characterized by high rates of ECMO-associated complications and poor posttransplant outcomes. More recently, ECMO-BTLT has garnered success in preserving patients' physiologic condition and candidacy prior to lung transplant due to technological advances and improved management. Despite recent growth, clinical practice surrounding use of ECMO-BTLT remains variable, with little data to inform optimal patient selection and management. Although many questions remain, the use of ECMO-BTLT has shown promising outcomes suggesting that ECMO-BTLT can be an effective strategy to ensure that complex and rapidly decompensating patients with end-stage lung disease can be safely transplanted with good outcomes. Further studies are needed to refine and inform practice patterns, management, and lung allocation in this high-risk and fragile patient population.

Month-long Respiratory Support by a Wearable Pumping Artificial Lung in an Ovine Model

BACKGROUND

A wearable artificial lung could improve lung transplantation outcomes by easing implementation of physical rehabilitation during long-term pretransplant respiratory support. The Modular Extracorporeal Lung Assist System (ModELAS) is a compact pumping artificial lung currently under development. This study evaluated the long-term in vivo performance of the ModELAS during venovenous support in awake sheep. Feedback from early trials and computational fluid dynamic analysis guided device design optimization along the way.

METHODS

The ModELAS was connected to healthy sheep via a dual-lumen cannula in the jugular vein. Sheep were housed in a fixed-tether pen while wearing the device in a holster during support. Targeted blood flow rate and support duration were 2-2.5 L/min and 28-30 days, respectively. Anticoagulation was maintained via systemic heparin. Device pumping and gas exchange performance and hematologic indicators of sheep physiology were measured throughout support.

RESULTS

Computational fluid dynamic-guided design modifications successfully decreased pump thrombogenicity from initial designs. For the optimized design, 4 of 5 trials advancing past early perioperative and cannula-related complications lasted the full month of support. Blood flow rate and CO2 removal in these trials were 2.1 ± 0.3 L/min and 139 ± 15 mL/min, respectively, and were stable during support. One trial ended after 22 days of support due to intradevice thrombosis. Support was well tolerated by the sheep with no signs of hemolysis or device-related organ impairment.

CONCLUSIONS

These results demonstrate the ability of the ModELAS to provide safe month-long support without consistent deterioration of pumping or gas exchange capabilities.

Characteristics of Patients Managed without Positive Pressure Ventilation While on Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome

Background: Extracorporeal membrane oxygenation (ECMO) has expanding indications for cardiopulmonary resuscitation including severe acute respiratory distress syndrome (ARDS). Despite the adjunct of ECMO for patients with severe ARDS, they often have prolonged mechanical ventilation and are subject to many of its inherent complications. Here, we describe patients who were cannulated for venovenous (VV) ECMO and were taken off positive pressure ventilation. Methods: This is a primary analysis of patients admitted at a tertiary medical center between the dates of August 2014 to January 2020 who were cannulated to ECMO for refractory respiratory failure. We included all patients ≥18 years old. Patients who were extubated or had a tracheostomy and taken off positive pressure while on ECMO were classified as “off positive pressure ventilation (PPV)” and were compared to patients who remained “on PPV” while on ECMO. Primary outcome was survival to hospital discharge. Secondary outcomes were ventilator free days at 30 days and 60 days after ECMO cannulation, time from cannulation to date of first out-of-bed (OOB), and hospital length of stay (LOS). Patient characteristics were derived from routine clinical information in the electronic health record (EHR). Categorical characteristics were compared using chi-square test or Fisher exact test. Continuous characteristics were compared using independent samples t-test or Wilcoxon–Mann–Whitney test. p-values were reported from all analysis. Results: Sixty-five patients were included in this retrospective analysis. Forty-eight were managed on ECMO with PPV and 17 patients were removed from PPV. Patients removed from PPV had significantly higher lung injury scores prior to cannulation (2.5 ± 0.6 vs. 1.04 ± 0.3; p = 0.031) and non-significantly longer duration of ventilation prior to ECMO (6.1 days ± 2.1 vs. 5.0 days ± 01.1; p = 0.634). One hundred percent (100%) of patients removed from PPV survived to hospital discharge compared to 45% who received PPV throughout their duration of ECMO management (p < 0.001). The mean ventilator free days at day 60 was 15 with PPV and 36 without PPV (p = 0.003). The average duration from cannulation to mobilization (i.e., out-of-bed) was 18 days with PPV and 7 days without PPV (p = 0.015). Conclusions: Patients taken off PPV while on ECMO had a very high likelihood of survival to discharge and were mobilized in half as many days. While this likely reflects patient selection, the benefit of early mobilization is well documented and the approach of extubating while on ECMO warrants further investigation.

Artificial lungs--Where are we going with the lung replacement therapy?

Lung transplantation may be a final destination therapy in lung failure, but limited donor organ availability creates a need for alternative management, including artificial lung technology. This invited review discusses ongoing developments and future research pathways for respiratory assist devices and tissue engineering to treat advanced and refractory lung disease. An overview is also given on the aftermath of the coronavirus disease 2019 pandemic and lessons learned as the world comes out of this situation. The first order of business in the future of lung support is solving the problems with existing mechanical devices. Interestingly, challenges identified during the early days of development persist today. These challenges include device-related infection, bleeding, thrombosis, cost, and patient quality of life. The main approaches of the future directions are to repair, restore, replace, or regenerate the lungs. Engineering improvements to hollow fiber membrane gas exchangers are enabling longer term wearable systems and can be used to bridge lung failure patients to transplantation. Progress in the development of microchannel-based devices has provided the concept of biomimetic devices that may even enable intracorporeal implantation. Tissue engineering and cell-based technologies have provided the concept of bioartificial lungs with properties similar to the native organ. Recent progress in artificial lung technologies includes continued advances in both engineering and biology. The final goal is to achieve a truly implantable and durable artificial lung that is applicable to destination therapy.

Awake veno-arterial extracorporeal membrane oxygenation in patients with perioperative period acute heart failure in cardiac surgery

Background

Extracorporeal membrane oxygenation (ECMO) is an effective extracorporeal life support technology that has been applied to treat cardiorespiratory failure patients. Some medical centers have started using ECMO on awake, non-intubated, spontaneously breathing patients, as this strategy offers several benefits over mechanical ventilation. However, most awake-ECMO methods focus on venovenous ECMO, and few cases of awake veno-arterial ECMO (V-A ECMO) have been reported, especially in perioperative acute heart failure. Therefore, our study aimed to examine awake—V-A ECMO cases that were not given continuous sedation or invasive mechanical ventilation (IMV) during perioperative heart failure.

Method

In total, 40 ECMO patients from December 2013 to November 2019 were divided into 2 groups (the awake-ECMO group and the asleep-ECMO group) according to the ventilation use. The demographics, patient outcomes, and ECMO parameters were collected and retrospectively analyzed.

Results

We identified 12 cases of awake ECMO without continuous ventilation, and 28 cases of simultaneous IMV and ECMO (asleep ECMO). Awake-ECMO patients showed fewer complications and better outcomes compared to ventilation patients. All patients in the awake group were successfully weaned off ECMO, while only 5 (18%) patients were weaned off ECMO in the asleep group. Furthermore, 9 (75%) patients survived until discharge in the awake group vs. 3 (11%) in the asleep group; 3 patients died of septic shock after weaning in the awake group, while 25 patients died of septic shock, hemodynamic disorder, bleeding, cerebral hemorrhage, etc., in the asleep group. These complications, including bleeding, pneumonia, hemolysis, and abdominal distension, etc., occurred less frequently in the asleep group compared to the awake group (P<0.05).

Conclusions

Awake V-A ECMO is an effective, feasible, and safe strategy in patients with perioperatively acute heart failure and can be applied as a bridge to cardiac function recovery or transplantation.

Extubation and Noninvasive Ventilation of Patients Supported by Extracorporeal Life Support for Cardiogenic Shock: A Single-Center Retrospective Observational Cohort Study

Background:

Temporary extracorporeal life support (ECLS) by venoarterial extracorporeal membrane oxygenation is an emerging therapy for patients with severe, ongoing cardiogenic shock. After stabilization of the hemodynamic status and end-organ function, sedation weaning, extubation, and noninvasive ventilation (NIV) can be attempted. The goal of this study was to analyze the feasibility of extubation and NIV during versus after ECLS for cardiogenic shock.

Methods:

Single-center retrospective observational study of 132 patients undergoing ECLS due to severe cardiogenic shock between January 2015 and December 2016 at a tertiary care university hospital.

Results:

Patients received ECLS due to acute myocardial infarction (20.6%), ongoing cardiogenic shock (15.2%), postoperative low-cardiac-output syndrome (24.2%), and extracorporeal cardiopulmonary resuscitation (40.2%). Overall, intensive care unit survival was 44.7%. Sixty-nine (52.3%) patients could never be extubated. Forty-three (32.6%) were extubated while on ECLS support (group 1) and 20 (15.1%) were extubated after weaning from ECLS (group 2). Patients extubated during ECLS had a significantly shorter total time on ventilator (P = .003, mean difference: −284 hours [95% confidence limits: −83 to −484]) and more invasive ventilation free days (P = .0018; mean difference 8 days [95%CL: 2-14]). Mortality and NIV failure rates were similar between groups.

Conclusions:

Extubation and NIV are feasible in patients who stabilize during ECLS therapy. Further studies need to address whether extubation has the potential to improve patients outcome or if the feasibility to extubate is a surrogate for disease severeness.

Echocardiography-Guided Dual-Lumen Venovenous Extracorporeal Membrane Oxygenation Cannula Placement in the ICU-A Retrospective Review

OBJECTIVE

The most effective method of image guidance for venovenous extracorporeal membrane oxygenation is not known. The authors' objectives were to define the frequency of successful initial cannulation using echocardiographic guidance in the intensive care unit, as well as to determine the frequency of subsequent adjustments. Additional aims were to illustrate cannula malposition problems and to describe features associated with difficult cannulation.

DESIGN

Retrospective consecutive case series analysis.

SETTING

Single tertiary care university hospital.

PARTICIPANTS

Forty-five patients treated with venovenous extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The most common causes of respiratory failure were pneumonia, aspiration, and inhalational burn injury. Sixty-two percent survived to discharge. Initial cannulation was successful in 39 cases (87%). Adverse events included 5 cases of cannula malposition and 1 case of hemorrhagic shock. During the course of extracorporeal membrane oxygenation, 17 patients (38%) required echo-guided cannula position adjustments. There were no fatal complications. Factors associated with difficult cannulation included extremes of size, a prominent Eustachian valve, and an anterior guidewire bending in the right atrium. Younger age was associated positively with survival. There was no significant association between adverse events during cannulation and survival.

CONCLUSIONS

Dual-lumen venovenous extracorporeal membrane oxygenation cannulation in the intensive care unit under echo guidance has a high initial success rate, but many patients require subsequent repositioning. Echocardiography can define cannula position in sufficient detail to identify malposition precisely and to guide repositioning.

Spontaneous breathing in patients with severe acute respiratory distress syndrome receiving prolonged extracorporeal membrane oxygenation

Background

The use of extracorporeal membrane oxygenation (ECMO) in awake, spontaneously breathing and non-intubated patients (awake ECMO) may be a novel therapeutic strategy for severe acute respiratory distress syndrome (ARDS) patients. The purpose of this study is to assess the feasibility and safety of awake ECMO in severe ARDS patients receiving prolonged ECMO (> 14 days).

Methods

We describe our experience with 12 consecutive severe ARDS patients (age, 39.1 ± 16.4 years) supported with awake ECMO to wait for native lung recovery during prolonged ECMO treatment from July 2013 to January 2018. Outcomes are reported including the hospital mortality, ECMO-related complications and physiological data on weaning from invasive ventilation.

Results

The patients received median 26.0 (15.5, 64.8) days of total ECMO duration in the cohort. The longest ECMO support duration was 121 days. Awake ECMO and extubation was implemented after median 10.2(5.0, 42.9) days of ECMO. Awake ECMO was not associated with increased morbidity. The total invasive ventilation duration, lengths of stay in the ICU and hospital in the cohort were 14.0(12.0, 37.3) days, 33.0(22.3, 56.5) days and 46.5(27.3, 84.8) days, respectively. The hospital mortality rate was 33.3% (4/12) in the cohort. Survivors had more stable respiratory rate and heart rate after extubation when compared to the non-survivors.

Conclusions

With carefully selected patients, awake ECMO is a feasible and safe strategy for severe pulmonary ARDS patients receiving prolonged ECMO support to wait for native lung recovery.

Bridging to lung transplantation with double-lumen venovenous extracorporeal membrane oxygenation

BACKGROUND

Double-lumen venovenous extracorporeal membrane oxygenation may be used as a bridge to lung transplantation. Predictors of outcome with this strategy have not been well described.

METHODS

All patients with irreversible lung disease who developed acute pulmonary failure and required double-lumen venovenous extracorporeal membrane oxygenation as a bridge to decision or lung transplant at our institution were included in this study. Survival of the extracorporeal membrane oxygenation patients was compared with listed patients who did not require extracorporeal membrane oxygenation with lung allocation score in the highest 10% for the same period.

RESULTS

Fifteen patients (46 ± 17 years old) received double-lumen venovenous extracorporeal membrane oxygenation cannula. Mean length of extracorporeal membrane oxygenation support was 18.2 (1-60) days. Of these, seven patients were bridged to lung transplant, six died on extracorporeal membrane oxygenation, and two weaned to recovery. Amount of red blood cell transfusion was significantly higher (3.3 vs 18.5 U, p = 0.003) and lowest oxygen saturation was significantly lower in non-survivors (84.5% vs 66.3%, p = 0.002). Of the seven patients who were already listed for lung transplant at the onset of extracorporeal membrane oxygenation, five were transplanted. Overall survival to hospital discharge was 60%. Survival of patients with lung allocation score in the highest 10% (average lung allocation score 83.4) in the same period was 80%.

CONCLUSION

Double-lumen venovenous extracorporeal membrane oxygenation cannula is a feasible option to bridge patients to decision or lung transplantation. Blood transfusion requirement and low oxygen saturation are markers of poor prognosis. Listing status at the time of cannulation and ambulation during extracorporeal membrane oxygenation support may be important indicators of good outcome.

Twenty-year experience with extracorporeal life support as bridge to lung transplantation

OBJECTIVES

Extracorporeal life support is increasingly used to bridge deteriorating candidates to lung transplantation. Nevertheless, only few systematic reports with a limited number of patients exist describing this practice and its changes over time.

METHODS

We retrospectively reviewed our institutional database and performed an era analysis to identify trends over time and risk factors for mortality. After applying propensity score matching, outcomes of bridged patients were compared with those of standard lung transplantation recipients.

RESULTS

Extracorporeal life support was used in 120 patients as an intention to bridge to lung transplantation. Eleven patients (9.2%) were bridged between 1998 and 2004, 39 patients (32.5%) were bridged between 2005 and 2010, and 70 patients were bridged (58.3%) between 2010 and 2017. In the first era, the main bridging modality was venoarterial-extracorporeal membrane oxygenation (n = 10, 90.9%), whereas venovenous devices were primarily used in later eras (second era: n = 18, 46.2%; third era: n = 39, 55.8%). In the second and third eras, 9 patients (23.1%) and 24 patients (34.3%) could be bridged awake. Short-term outcome was poor in the first era, with only 36.4% of patients discharged alive but improved in later eras (53.8% and 77.1%; P = .002). Extracorporeal life support-bridged patients showed an impaired short-term outcome compared with standard recipients. However, survival conditional on 90 days did not differ among the groups (P = .178). In univariate and multivariate analyses, awake extracorporeal life support was protective for survival, whereas acute retransplantation was a risk factor for mortality.

CONCLUSIONS

Over the past 2 decades, the role of extracorporeal life support bridging evolved from an acute rescue therapy to a semi-elective procedure. Stratified outcome analysis revealed that extracorporeal life support bridging yielded similar long-term survival compared with nonbridged patients.

Pressure ulcers in paediatric patients on extracorporeal membrane oxygenation

It has been shown that pressure ulcer formation in critically ill paediatric patients increases morbidity and mortality. We sought to identify factors associated with pressure ulcer formation in paediatric patients on extracorporeal membrane oxygenation (ECMO). From December 2014 to 2015, we identified patients at our institution who developed a pressure ulcer to create two cohorts: ulcer and no ulcer. Variables of interest included: type of ECMO, ECMO indication, hours on ECMO, location of cannulas, volume of crystalloid and blood products received during the first 7 days or during the length of the ECMO run, albumin and lactate levels on the day of cannulation, and presence of vasopressor support or steroid therapy. Of 43 patients studied, 11 (25.5%) developed a pressure ulcer. Patients that developed ulcers were older (P = 0.001) and weighed more (P = 0.006). Femoral cannulation was more frequent in the ulcer group (36.4% vs 6.3%, P = 0.029), and duration of ECMO was longer (P = 0.007). Age, weight, duration of ECMO, and femoral cannulation may contribute to the development of pressure ulcers in children who require ECMO support. Further analysis is imperative to identify specific techniques and protocols that will prevent pressure ulcers in this critically ill population.

Recent advances in lung transplantation

Lung transplantation can improve quality of life and prolong survival for individuals with end-stage lung disease, and many advances in the realms of both basic science and clinical research aspects of lung transplantation have emerged over the past few decades. However, many challenges must yet be overcome to increase post-transplant survival. These include successfully bridging patients to transplant, expanding the lung donor pool, inducing tolerance, and preventing a myriad of post-transplant complications that include primary graft dysfunction, forms of cellular and antibody-mediated rejection, chronic lung allograft dysfunction, and infections. The goal of this manuscript is to review salient recent and evolving advances in the field of lung transplantation.

Extracorporeal lung support

PURPOSE OF REVIEW

The applications for extracorporeal membrane oxygenation for lung support are constantly evolving. This review highlights fundamental concepts in extracorporeal lung support and describes directions for future research.

RECENT FINDINGS

Since the 1950s, extracorporeal lung support has experienced continuous advancements in circuit design and safety in acute respiratory distress syndrome, chronic obstructive pulmonary disease exacerbations, as a bridge to transplantation, intraoperative cardiopulmonary support, and for transportation to referral centers. Patients on extracorporeal membrane oxygenation are now capable of being awake, extubated, and ambulatory for accelerated recovery or optimization for transplantation.

SUMMARY

Extracorporeal lung support is a safe and an easily implemented intervention for refractory respiratory failure. Recent advances have extended its use beyond acute illnesses and the developments for chronic support will facilitate the development of durable devices and possible artificial lung development.

Tracheostomy as a bridge to spontaneous breathing and awake-ECMO in non-transplant surgical patients

AIMS

The tracheostomy is a frequently used procedure for the respiratory weaning of ventilated patients allows sedation free ECLS use in awake patient. The aim of this study is to assess the possibility and highlight the benefits of lowering the impact of sedation in surgical non-transplant patients on ECLS. The specific objective was to investigate the use of tracheostomy as a bridge to spontaneous breathing on ECLS.

METHODS AND RESULTS

Of the 95 patients, 65 patients received a tracheostomy, and 5 patients were admitted with a tracheostoma. One patient was cannulated without intubation, one is extubated during ECLS course after 48 hours. 4 patients were extubated after weaning and the removal of ECLS. 19 patients died before the indication to tracheostomy was given.

CONCLUSION

Tracheostomy can bridge to spontaneous breathing and awake-ECMO in non-transplant surgical patients. The "awake ECMO" strategy may avoid complications related to mechanical ventilation, sedation, and immobilization and provide comparable outcomes to other approaches for providing respiratory support.

ECFS best practice guidelines: the 2018 revision

Developments in managing CF continue to drive dramatic improvements in survival. As newborn screening rolls-out across Europe, CF centres are increasingly caring for cohorts of patients who have minimal lung disease on diagnosis. With the introduction of mutation-specific therapies and the prospect of truly personalised medicine, patients have the potential to enjoy good quality of life in adulthood with ever-increasing life expectancy. The landmark Standards of Care published in 2005 set out what high quality CF care is and how it can be delivered throughout Europe. This underwent a fundamental re-write in 2014, resulting in three documents; center framework, quality management and best practice guidelines. This document is a revision of the latter, updating standards for best practice in key aspects of CF care, in the context of a fast-moving and dynamic field. In continuing to give a broad overview of the standards expected for newborn screening, diagnosis, preventative treatment of lung disease, nutrition, complications, transplant/end of life care and psychological support, this consensus on best practice is expected to prove useful to clinical teams both in countries where CF care is developing and those with established CF centres. The document is an ECFS product and endorsed by the CF Network in ERN LUNG and CF Europe.

Weaning from veno-venous extracorporeal membrane oxygenation: how I do it

Veno-venous extracorporeal membrane oxygenation (VV ECMO) is a rescue treatment for acute respiratory distress syndrome (ARDS) failing protective mechanical ventilation. It temporarily provides proper gas exchange: hypoxia is treated by adjusting the blood flow rate and fraction in spired oxygen over the ventilator (FiO2) on the extracorporeal membrane oxygenation (ECMO) circuit while CO2 removal is regulated by the ECMO fresh gas flow. Therefore, ventilator settings can be gradually reduced allowing the lungs to rest and recover. Nowadays, indications for ECMO referral and implantation are clearly formulated; on the contrary, little evidence currently exists to guide the process of weaning from ECMO support, especially concerning the timing during the course of lung healing. Therefore, indications to stop ECMO are less well standardized so that in clinical trials extracorporeal assistance is generally continued until lung recovery, with neither specific nor homogenous criteria for withdrawal. Notably, in almost all papers dealing with data on VV ECMO support, the management of weaning and the weaning procedure itself are not described. The aim of this paper is to make a picture of VV ECMO weaning, as it is performed in three European large volume intensive care units (ICUs) which represent referral centers for VV ECMO treatment. We focused on data concerning the timing of VV ECMO weaning and parameters at the time of weaning, in order to assess adequacy and safety of VV ECMO removal.

Ambulatory veno-venous extracorporeal membrane oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) is used for support in patients with severe respiratory failure. The method allows extracorporeal gas exchange and may replace the patient's lung function for weeks and even years. ECMO is not a contraindication for lung transplant. The most important factor for a good outcome is the physiological status of the patient when accepted for transplantation. Ambulatory ECMO makes it possible for the patient to exercise and walk, and provides the best outcome for high risk patients in severe respiratory failure. Ambulatory ECMO is safe in the hands of skilled personnel and prevents critical illness neuropathy and myopathy during prolonged treatments in the intensive care unit.

Anticoagulation Practices during Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure. A Systematic Review

BACKGROUND

The optimal anticoagulation strategy for venovenous extracorporeal membrane oxygenation (VV-ECMO) is not known.

OBJECTIVES

To evaluate the safety of anticoagulation strategies and monitoring during VV-ECMO for respiratory failure.

DATA SOURCES

We conducted a systematic review to evaluate the association between anticoagulation strategies during VV-ECMO and prespecified outcomes, including major bleeding episodes, thrombotic events, and in-hospital mortality. We included articles published between 1977 and January 30, 2015. Study quality was assessed using the Newcastle-Ottawa scoring system. A separate meta-analysis was not planned.

DATA EXTRACTION

Data were independently extracted by two authors and collected on a standardized report form.

SYNTHESIS

A total of 18 studies (n = 646) were included; 17 studies enrolled patients with acute respiratory distress syndrome. Across all studies, the duration of VV-ECMO support ranged from 4 to 20 days. Patients received an average of 2.3 (±3.9) units of transfused red blood cells per day. The bleeding rate across all studies was 16%, and the rate of thrombosis was 53%. Among seven studies (199 patients) targeting a specified activated partial thromboplastin time (aPTT), there were 37 (19%) major bleeding episodes and 53 (27%) major thromboses. Among five studies (43 patients) with aPTT targets of 60 seconds or greater, there were 24 (56%) bleeding episodes and 3 (7%) clotting events. Three studies (156 patients) with an aPTT target under 60 seconds reported 13 (8%) and 50 (32%) significant bleeding and thrombotic events, respectively. The most commonly reported thrombotic events were circuit-related clotting and deep-vein thrombosis. Mortality during VV-ECMO varied across the studies, ranging from 0 to at least 50% at heterogeneous time points. The total number of deaths for all studies combined was 186 (29%).

CONCLUSIONS

The role and optimal therapeutic targets for anticoagulation during VV-ECMO are unclear. Previously published studies are limited by retrospective, observational design, small cohorts, and patient heterogeneity. The clinical significance of reported thrombotic complications is largely unknown. This systematic review underscores the need for randomized controlled trials of anticoagulation strategies for patients undergoing VV-ECMO for respiratory failure.

Sequential use of extracorporeal devices to avoid mechanical ventilation in a patient with complicated pulmonary fibrosis

Extracorporeal lung assist devices are widely used these days for a growing number of indications. We report the case of a patient managed with three different flow-range devices sequentially, enabling us to avoid mechanical ventilation. Handling and ethics of this approach are discussed.

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.

Extracorporeal techniques in acute respiratory distress syndrome

Extracorporeal membrane oxygenation (ECMO) was first introduced for patients with acute respiratory distress syndrome (ARDS) in the 1970s. However, enthusiasm was tempered due to the high mortality seen at that time. The use of ECMO has grown considerably in recent years due to technological advances and the evidence suggesting potential benefit. While the efficacy of ECMO has yet to be rigorously demonstrated with high-quality evidence, it has the potential not only to have a substantial impact on outcomes, including mortality, but also to change the paradigm of ARDS management.

Spontaneously Breathing Extracorporeal Membrane Oxygenation Support Provides the Optimal Bridge to Lung Transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is being increasingly used as a bridge to lung transplantation. Small, single-institution series have described increased success using ECMO in spontaneously breathing patients compared with patients on ECMO with mechanical ventilation, but this strategy has not been evaluated on a large scale.

METHODS

Using the United Network for Organ Sharing database, all adult patients undergoing isolated lung transplantation from May 2005 through September 2013 were identified. Patients were categorized by their type of pretransplant support: no support, ECMO only, invasive mechanical ventilation (iMV) only, and ECMO + iMV. Kaplan-Meier survival analysis with log-rank testing was performed to compare survival based on type of preoperative support. A Cox regression model was used to determine whether type of preoperative support was independently associated with survival, using previously established predictors of survival as covariates.

RESULTS

Approximately 12,403 primary adult pulmonary transplantations were included in this analysis. Sixty-five patients (0.52%) were on ECMO only, 612 (4.93%) required only iMV, 119 (0.96%) were on ECMO + iMV, and the remaining 11,607 (94.6%) required no invasive support before transplantation. One-year survival was decreased in all patients requiring support, regardless of type. However, mid-term survival was similar between patients on ECMO alone and those not on support but significantly worse with patients requiring iMV only or ECMO + iMV. In multivariable analysis, ECMO + iMV and iMV alone were independently associated with decreased survival compared with nonsupport patients, whereas ECMO alone was not significant.

CONCLUSIONS

In patients with worsening pulmonary disease awaiting lung transplantation, those supported via ECMO with spontaneous breathing demonstrated improved survival compared with other bridging strategies.

Lung Allocation Score: A Single-Center Simulation

BACKGROUND

The lung allocation score (LAS) was introduced in the United States in May 2005 with the main goal of reducing the waiting list mortality of patients with end-stage lung diseases, but also to enhance the lung transplant benefit and improve the management of urgent candidates. Several papers have reported that LAS resulted in a reduction of the waiting list mortality but no significant survival benefit was noted.

METHODS

We evaluate the usefulness of LAS as a predictor for lung transplantation outcome in 123 patients listed for lung transplantation in an Italian center. Primary endpoints were waiting list mortality and posttransplant mortality at 1 year; secondary endpoints included perioperative circulatory support, cardiopulmonary bypass, primary graft dysfunction, and long-term survival after transplantation.

RESULTS

We observed the absence of correlation between LAS and waiting list mortality. The LAS did not affect the long-term survival in our population.

CONCLUSIONS

High LAS was predictive of primary graft dysfunction of grade 3 in the first 72 hours after transplantation.

"Awake" Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant

Mortality of patients awaiting lung transplant remains a significant problem as the number of patients on the waiting list far surpasses the number of donor organs available. Interest in the use of "awake" extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplant has emerged because this strategy offers several benefits over mechanical ventilation. This article provides a review of relevant literature and discusses indications and complications of awake ECMO therapy, cannulation strategies, and nursing considerations for this patient population.

Adult venovenous extracorporeal membrane oxygenation for severe respiratory failure: Current status and future perspectives

Extracorporeal membrane oxygenation (ECMO) for severe acute respiratory failure was proposed more than 40 years ago. Despite the publication of the ARDSNet study and adoption of lung protective ventilation, the mortality for acute respiratory failure due to acute respiratory distress syndrome has continued to remain high. This technology has evolved over the past couple of decades and has been noted to be safe and successful, especially during the worldwide H1N1 influenza pandemic with good survival rates. The primary indications for ECMO in acute respiratory failure include severe refractory hypoxemic and hypercarbic respiratory failure in spite of maximum lung protective ventilatory support. Various triage criteria have been described and published. Contraindications exist when application of ECMO may be futile or technically impossible. Knowledge and appreciation of the circuit, cannulae, and the physiology of gas exchange with ECMO are necessary to ensure lung rest, efficiency of oxygenation, and ventilation as well as troubleshooting problems. Anticoagulation is a major concern with ECMO, and the evidence is evolving with respect to diagnostic testing and use of anticoagulants. Clinical management of the patient includes comprehensive critical care addressing sedation and neurologic issues, ensuring lung recruitment, diuresis, early enteral nutrition, treatment and surveillance of infections, and multisystem organ support. Newer technology that delinks oxygenation and ventilation by extracorporeal carbon dioxide removal may lead to ultra-lung protective ventilation, avoidance of endotracheal intubation in some situations, and ambulatory therapies as a bridge to lung transplantation. Risks, complications, and long-term outcomes and resources need to be considered and weighed in before widespread application. Ethical challenges are a reality and a multidisciplinary approach that should be adopted for every case in consideration.

Vascular access for extracorporeal life support: tips and tricks

In thoracic surgery, extracorporeal life support (ECLS) techniques are performed to (I) provide a short to mid term extracorporeal mechanical support; (II) realize the gas exchanges; and (III)-depending the configuration of the circuit-substitute the failed heart function. The objective of this review is to describe the rational of the different ECLS techniques used in thoracic surgery and lung transplantation (LTx) with a specific attention to the vascular access. Venovenous extracorporeal membrane oxygenation (VV ECMO) is the most common ECLS technique used in thoracic surgery and represents the best strategy to support the lung function. VV ECMO needs peripheral vascular access. The selection between his double-site or single-site configuration should be decided according the level of O2 requirements, the nosological context, and the interest to perform an ECLS ambulatory strategy. Venoarterial (VA) ECMO uses peripheral and/or central cannulation sites. Central VA ECMO is mainly used in LTx instead a conventional cardiopulmonary bypass (CPB) to decrease the risk of hemorrhagic issues and the rate of primary graft dysfunction (PGD). Peripheral VA ECMO is traditionally realized in a femoro-femoral configuration. Femoro-femoral VA ECMO allows a cardiocirculatory support but does not provide an appropriate oxygenation of the brain and the heart. The isolated hypercapnic failure is currently supported by extracorporeal CO2 removal (ECCO2R) devices inserted in jugular or subclavian veins. The interest of the Novalung (Novalung GmbH, Hechingen, Germany) persists due to his central configuration indicated to bridge to LTx patients suffering from pulmonary hypertension. The increasing panel of ECLS technologies available in thoracic surgery is the results of a century of clinical practices, engineering progress, and improvements of physiological knowledges. The selection of the ECLS technique-and therefore the vascular access to implant the device-for a given nosological context trends to be defined according an evidence-based medicine.

Venovenous Extracorporeal Membrane Oxygenation in Intractable Pulmonary Insufficiency: Practical Issues and Future Directions

Venovenous extracorporeal membrane oxygenation (vv-ECMO) is a highly invasive method for organ support that is gaining in popularity due to recent technical advances and its successful application in the recent H1N1 epidemic. Although running a vv-ECMO program is potentially feasible for many hospitals, there are many theoretical concepts and practical issues that merit attention and require expertise. In this review, we focus on indications for vv-ECMO, components of the circuit, and management of patients on vv-ECMO. Concepts regarding oxygenation and decarboxylation and how they can be influenced are discussed. Day-to-day management, weaning, and most frequent complications are covered in light of the recent literature.

Clinical risk factors for primary graft dysfunction in a low-volume lung transplantation center

Primary graft dysfunction (PGD) is a severe acute lung injury syndrome following lung transplantation. Previous studies of clinical risk factors, including a multicenter prospective cohort trial, have identified a number of recipient, donor, and operative variables related to Grade 3 PGD. The aim of this study was to validate these risk factors in a lung transplantation center with a low volume of procedures. We conducted a retrospective cohort study of 45 consecutive lung transplantations performed between January 2011 and September 2013. PGD was defined according to the International Society for Heart and Lung Transplantation grading scale. Risk factors were evaluated independently and the significant confounders entered into multivariable logistic regression models. The overall incidence of Grade 3 PGD was 35.5% at T24, 17.7% at T48, and 15.5% at T72. The following risk factors were associated with Grade 3 PGD at the indicated time points: recipient female gender at T24 (P=.034), mixed diagnoses at T72 (P=.047), ECMO bridge-to-lung transplantation at T24 (P=.0004) and at T48 (P=.038), donor causes of death different from stroke and trauma at T24 (P=.019) and T72 (P=.014), blood transfusions during surgery at T24 (P=.001), intraoperative venoarterial ECMO T24 (P<.0001). Multivariate analysis at T24 identified recipient female gender and intraoperative venoarterial ECMO as risk factors (P=.010 and P=.018, respectively). This study demonstrated that risk factors for severe PGD in a low-volume center were similar to international reports in prevalence and type. ECMO bridge-to-lung transplantation emerged as a risk factor previously underestimated.

Extracorporeal Membrane Oxygenation Applications in Cardiac Critical Care

The use of extracorporeal membrane oxygenation therapy (ECMO) in cardiac critical care has steadily increased over the past decade. Significant improvements in the technology associated with ECMO have propagated this recent resurgence and contributed to improved patient outcomes in the fields of cardiac and transplant (heart and lung) surgery. Specifically, ECMO is being increasingly utilized as a bridge to heart and lung transplantation, as well as to ventricular assist device placement. ECMO is also employed during the administration of cardiopulmonary resuscitation, known as extracorporeal life support. In this review, we examine the recent literature regarding the applications of ECMO and also describe emerging topics involving current ECMO management strategies.

Ambulatory extracorporeal membrane oxygenation as a bridge to lung transplantation: walking while waiting

The proportion of critically ill patients awaiting lung transplantation has increased since the implementation of the Lung Allocation Score (LAS) in 2005. Critically ill patients comprise a sizable proportion of wait-list mortality and are known to experience increased posttransplant complications. These critically ill patients have been successfully bridged to lung transplantation with extracorporeal membrane oxygenation (ECMO), but historically these patients have required excessive sedation, been immobile, and have had difficult functional recovery in the posttransplant period and high mortality. One solution to the deconditioning often seen in critically ill patients is the implementation of rehabilitation and ambulation while awaiting transplantation on ECMO. Ambulatory ECMO programs of this nature have been developed in an attempt to provide rehabilitation, physical therapy, and minimization of sedation prior to lung transplantation to improve both surgical and posttransplant outcomes. Favorable outcomes have been reported using this novel approach, but how and where this strategy should be implemented remain unclear. In this commentary, we review the currently available literature for ambulation and rehabilitation during ECMO support as a bridge to lung transplantation, discuss future directions for this technology, and address the important issues of resource allocation and regionalization of care as they relate to ambulatory ECMO.

Critically Ill Patients with Interstitial Lung Disease

Interstitial lung disease (ILD) is a clinical syndrome of various etiologies and histopathologic categorization that, when clinically significant, impair respiratory function. Patients with ILD may develop critical illness from respiratory failure, nonpulmonary organ failure, or after surgical procedures. Additionally, the intensivist must be adept at recognizing exacerbation syndromes, which can complicate the disease course of some forms of ILD. This article discusses mechanical ventilation, noninvasive mechanical ventilation, exacerbation syndromes, and surgical concerns for patients with ILD who are critically ill.

Extracorporeal life support: experience with 2,000 patients

This is a review of the University of Michigan experience with extracorporeal life support (ECLS) also known as extracorporeal membrane oxygenation (ECMO). Two thousand patients were managed with ECMO from 1973 to 2010. The first 1,000 patients were reported previously. Of the 2,000 patients, 74% were weaned from ECLS, and 64% survived to hospital discharge. In patients with respiratory failure, survival to hospital discharge was 84% in 799 neonates, 76% in 239 children, and 50% in 353 adults. Survival in patients with cardiac failure was 45% in 361 children and 38% in 119 adults. ECLS during extracorporeal cardiopulmonary resuscitation was performed in 129 patients, with 41% surviving to discharge. Survival decreased from 74 to 55% between the first and second 1,000 patients. The most common complication was bleeding at sites other than the head, with an incidence of 39%, and the least frequent complication was pump malfunction, with a 2% incidence. Intracranial bleeding or infarction occurred in 8% of patients, with a 43% survival rate. This is the largest series of ECLS at one institution reported in the world to date. Our experience has shown that ECLS saves lives of moribund patients with acute pulmonary and cardiac failure in all age groups.

Effects of ultraprotective ventilation, extracorporeal carbon dioxide removal, and spontaneous breathing on lung morphofunction and inflammation in experimental severe acute respiratory distress syndrome

BACKGROUND

To investigate the role of ultraprotective mechanical ventilation (UP-MV) and extracorporeal carbon dioxide removal with and without spontaneous breathing (SB) to improve respiratory function and lung protection in experimental severe acute respiratory distress syndrome.

METHODS

Severe acute respiratory distress syndrome was induced by saline lung lavage and mechanical ventilation (MV) with higher tidal volume (VT) in 28 anesthetized pigs (32.8 to 52.5 kg). Animals (n = 7 per group) were randomly assigned to 6 h of MV (airway pressure release ventilation) with: (1) conventional P-MV with VT ≈6 ml/kg (P-MVcontr); (2) UP-MV with VT ≈3 ml/kg (UP-MVcontr); (3) UP-MV with VT ≈3 ml/kg and SB (UP-MVspont); and (4) UP-MV with VT ≈3 ml/kg and pressure supported SB (UP-MVPS). In UP-MV groups, extracorporeal carbon dioxide removal was used.

RESULTS

The authors found that: (1) UP-MVcontr reduced diffuse alveolar damage score in dorsal lung zones (median[interquartile]) (12.0 [7.0 to 16.8] vs. 22.5 [13.8 to 40.8]), but worsened oxygenation and intrapulmonary shunt, compared to P-MVcontr; (2) UP-MVspont and UP-MVPS improved oxygenation and intrapulmonary shunt, and redistributed ventilation towards dorsal areas, as compared to UP-MVcontr; (3) compared to P-MVcontr, UP-MVcontr and UP-MVspont, UP-MVPS yielded higher levels of tumor necrosis factor-α (6.9 [6.5 to 10.1] vs. 2.8 [2.2 to 3.0], 3.6 [3.0 to 4.7] and 4.0 [2.8 to 4.4] pg/mg, respectively) and interleukin-8 (216.8 [113.5 to 343.5] vs. 59.8 [45.3 to 66.7], 37.6 [18.8 to 52.0], and 59.5 [36.1 to 79.7] pg/mg, respectively) in dorsal lung zones.

CONCLUSIONS

In this model of severe acute respiratory distress syndrome, MV with VT ≈3 ml/kg and extracorporeal carbon dioxide removal without SB slightly reduced lung histologic damage, but not inflammation, as compared to MV with VT = 4 to 6 ml/kg. During UP-MV, pressure supported SB increased lung inflammation.

[The place of extra-corporeal oxygenation in pulmonary diseases]

Extra-corporeal membrane oxygenation (ECMO) effectively replaces the lung in providing oxygenation and carbon dioxide (CO2) removal. For some years, and in parallel to the H1N1 influenza pandemic, this technique has gained interest in relation to significant technological improvements, leading to new concepts of "awake and mobile ECMO" or rehabilitation with ECMO. Finally, the publication of randomized controlled trials giving encouraging results in the adult respiratory distress syndrome (ARDS) has helped to validate this technique and further studies are warranted. This general review aims to outline the definition, classification and principles of ECMO and to give some current information about the indications and possibilities of the technique to the pulmonologist and intensivist. Further possible uses for this technique include extra-corporeal removal of CO2 during hypercapnic respiratory failure and assistance during lung transplantation from the preoperative to the early postoperative period.