Extracorporeal membrane oxygenation in adults for severe acute respiratory failure

The purpose of this review is to examine the indications of extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS). This technique of oxygenation has significantly increased worldwide with the H1N1 flu pandemic. The goal of ECMO is to maintain a safe level of oxygenation and controlled respiratory acidosis under protective ventilation. The enthusiasm for ECMO should not obscure the consideration for potential associated complications. Before widespread diffusion of ECMO, new trials should test the efficacy of early initiation or CO₂ removal in addition to, or even as an alternative to mechanical ventilation for severe ARDS.     

Long-term extracorporeal membrane oxygenation with minimal ventilatory support: a new paradigm for severe ARDS?

Pulmonary tuberculosis can lead to acute respiratory distress syndrome (ARDS) which is associated with high mortality. We report the case of a patient with pulmonary tuberculosis and severe ARDS (PaO2/FiO2<100 mmHg) who was initially managed with advanced up-to-date treatments (protective ventilation and extracorporeal membrane oxygenation, ECMO) but failed to improve. After a month of failure and the development of bilateral pneumothoraces, we drastically changed our therapeutic strategy: we maximized ECMO support to maintain oxygenation, we greatly reduced ventilation pressures and we left the pneumothoraces undrained. From then on, the patient improved and he eventually survived. This case suggests that ECMO permits large reductions in lung inflation and ventilation to rest the lungs, while maintaining acceptable oxygenation. The combination of ECMO and markedly attenuated ventilation strategy may be effective in cases of severe ARDS.     

Severe acute respiratory distress syndrome secondary to acute pancreatitis successfully treated with extracorporeal membrane oxygenation in three patients.

OBJECTIVE: To review three patients who underwent extracorporeal membrane oxygenation (ECMO) for acute respiratory failure secondary to pancreatitis. SUMMARY BACKGROUND DATA: Severe acute pancreatitis often causes the acute respiratory distress syndrome (ARDS), and if ventilation is required, the mortality rate is more than 50%. If the ratio of PaO2/FiO2 falls below 100 mm Hg or the Murray lung injury score exceeds 3.5, the mortality rate rises to more than 80%. Three patients who have severe ARDS secondary to pancreatitis, who were hypoxic despite ventilation with 100% oxygen and high airway pressures, and who were all successfully treated with ECMO are reported here. The consensus here is that all three patients would have died without ECMO. METHODS: Retrospective chart review and discussion of the literature. RESULTS: Pre-ECMO data: mean PaO2/FiO2 59.3 mm Hg, mean Murray lung injury score 3.7, one patient administered 20 ppm inhaled nitric oxide. ECMO data: mean extracorporeal flow at initiation of ECMO 56.3 mL/kg per minute, all patients administered veno-venous ECMO, mean duration of ECMO 104.7 hours. All patients were successfully weaned from ECMO and extubated. One patient had a protracted hospital stay because of a colo-cutaneous fistula. All patients are long-term survivors. CONCLUSIONS: Extracorporeal membrane oxygenation proved an effective therapy for severe ARDS complicating acute pancreatitis. Extracorporeal membrane oxygenation was conducted without bleeding complications in these three patients.     

Extrakorporale Membranoxygenierung beim akuten Lungenversagen

After various observational studies demonstrated a benefit of extracorporeal membrane oxygenation (ECMO) in the therapy of severe acute respiratory distress syndrome (ARDS), ECMO now represents an important contribution for ARDS therapy using clinical algorithms despite a lack of positive controlled studies. In specialized centers patients with severe ARDS and imminent hypoxia despite intensive conventional therapy, are treated with ECMO using blood pumps and artificial membrane lungs (oxygenators) for extracorporeal lung assist. The development of new surface modifications, optimized oxygenators and miniaturized blood pumps should increase hemocompatibility and lead to simplified treatment as well as less complications. New oxygenators with significantly decreased blood resistance allow the clinical application of pumpless arteriovenous extracorporeal lung assist (ECLA). After these new developments indications for ECMO could be extended from use not only as ultimate ratio but to less severe ARDS to enable lung protective, less invasive mechanical ventilation.     

Polytrauma mit schwerem Lungenparenchymschaden

Extracorporeal membrane oxygenation (ECMO) is a technique for sustaining body oxygenation in case of respiratory failure. Since ECMO technology has undergone improvements resulting in better hemo-compatibility and reduced side effects, venovenous ECMO is a mostly accepted treatment of adult respiratory distress syndrome (ARDS). One should discuss the early initiation of ECMO therapy for post-traumatic respiratory failure. We report about a 23-year-old male and a 15-year-old female patient, who suffered polytrauma and received early treatment with ECMO because of severe lung contusion.     

Role of extracorporeal lung assist in the treatment of acute respiratory failure

For patients with most severe acute respiratory distress syndrome (ARDS) conservative treatment with lung protective ventilation is often not sufficient to prevent life-threatening hypoxemia and additional strategies are necessary. Extracorporeal lung assist (ECLA) or extracorporeal membrane oxygenation (ECMO) using capillary membrane oxygenators can provide sufficient gas exchange and lung rest. In 2 randomized trials mortality was unchanged for ECMO. Today an technically enhanced ECMO is used for most severe ARDS using clinical algorithm and different case studies demonstrated a survival rate about 56%. Today miniaturized ECMO with optimized blood pumps and oxygenators are available and could enhance safety and clinical management. Another approach is an arterio-venous pumpless interventional lung assist (ILA) with a low resistance oxygenator. Advantages seem a simplified clinical management and less blood trauma. At present new devices are developed for chronic respiratory failure or bridge to lung transplant. Oxygenators with even less flow resistance could be implanted paracorporeal using the right ventricle as driving force. An intravascular oxygenator has been developed using the combination of a miniaturized blood pump and an oxygenator for implantation in the vena cava. Well designed clinical trials are necessary to demonstrate a clinical benefit for these experimental devices.     

Extracorporeal membrane oxygenation and severe traumatic brain injury. Is the ECMO-therapy in traumatic lung failure and severe traumatic brain injury really contraindicated?

Veno-venous extracorporeal membrane oxygenation (ECMO) may be lifesaving in multiple injured patients with acute respiratory distress syndrome (ARDS) due to chest trauma. To prevent circuit thrombosis or thrombembolic complications during ECMO systemic anticoagulation is recommended. Therefore, ECMO treatment is contraindicated in patients with intracranial bleeding. The management of veno-venous ECMO without systemic anticoagulation in a patient suffering from traumatic lung failure and severe traumatic brain injury is reported.     

Early treatment with arteriovenous extracorporeal lung assist and high-frequency oscillatory ventilation in a case of severe acute respiratory distress syndrome

BACKGROUND: Lung protective ventilation can reduce mortality in acute respiratory distress syndrome (ARDS). However, many patients with severe ARDS remain hypoxemic and more aggressive ventilation is necessary to maintain sufficient gas exchange. Pumpless arteriovenous extracorporeal lung assist (av-ECLA) has been shown to remove up to 95% of the systemic CO(2) production, thereby allowing ventilator settings and modes prioritizing oxygenation and lung protection. High-frequency oscillatory ventilation (HFOV) is an alternative form of ventilation that may improve oxygenation while limiting the risk of further lung injury by using extremely small tidal volumes (VT). METHODS: We discuss the management of a patient suffering from severe ARDS as a result of severe bilateral lung contusions and pulmonary aspiration. RESULTS: Severe ARDS developed within 4 h after intensive care unit admission. Conventional mechanical ventilation (CV) with high-airway pressures and low VT failed to improve gas exchange. Av-ECLA was initiated to achieve a less aggressive ventilation strategy. VT was reduced to 2-3 ml/kg, but oxygenation did not improve and airway pressures remained high. HFOV (8-10 Hz) was started using a recruitment strategy and oxygenation improved within 2 h. After 5 days, the patient was switched back to CV uneventfully and av-ECLA was removed after 8 days. CONCLUSION: The combination of two innovative treatment modalities resulted in rapid stabilization and improvement of gas exchange during severe ARDS refractory to conventional lung protective ventilation. During av-ECLA, extremely high oscillatory frequencies were used minimizing the risk of baro- and volutrauma.     

Traumatic lung injury treated by extracorporeal membrane oxygenation (ECMO)

BACKGROUND: Conventional mechanical ventilation is the mainstay of treatment for severe respiratory failure associated with trauma. However, when extensive lung injury is present, this technique may not be sufficient to prevent hypoxia, and furthermore, may exacerbate pulmonary damage by barotrauma. Extracorporeal membrane oxygenation (ECMO) has been used successfully in critically ill adult trauma patients and can offer an additional treatment modality. This study reports the use of ECMO in a cohort of adults referred with severe respiratory failure following trauma. METHODS: Retrospective analysis over an 8-year period of all 28 adult patients referred to a single tertiary unit for ECMO support. Survival relative to Injury severity score (ISS), lung injury score (Murray grade), duration of treatment and patient age was evaluated. RESULTS: Twenty of 28 patients who received ECMO with severe trauma related respiratory failure (mean PaO2/FiO2 of 62 mmHg) survived. Most patients had long bone fractures, blunt chest trauma, or combined injuries. Lung injury and injury severity scores, patient age, ECMO duration and oxygenation indices pre-ECMO (PaO2/FiO2) were similar in both the survivor and non-survivor groups. CONCLUSION: A high proportion of trauma patients treated with ECMO for severe lung injury survived. This outcome appears to compare favourably to conventional ventilation techniques and may have a role in patients who develop acute severe respiratory distress associated with trauma.     

Extrakorporale Membranoxygenierung

Altough the concept of extracorporeal membrane oxygenation (ECMO) therapy has been established and used for over 30 years, in recent years the number of implanted ECMO systems has increased and it has developed into an integral component of the clinical routine. All forms of ECMO therapy can be summarized under the term extracorporeal life support (ECLS). The latest developments are surface-coated and miniaturized ECMO systems which allow the long-term support of critically ill patients. Severe lung failure with a normal cardiac index is treated by venovenous ECMO (vv-ECMO). The interventional lung assist/pumpless extracorporeal lung assist (iLA/PECLA) systems are mostly indicated for hypercapnic respiratory acidosis as is frequent with acute respiratory distress syndrome (ARDS). The support of ARDS patients with ECMO seems to improve outcome by allowing further protective lung ventilation. Cardiopulmonary failure is treated by venoarterial ECMO (va-ECMO) and is often used in an interdisciplinary setting in emergency rooms where survival of these patients is increased by up to 40%. Although clear indications are defined only a few risk analyses have been carried to show which patients benefit most from va-ECMO. The decision whether to implant a va-ECMO or not is still based on center and physician experience. To guarantee safe and high quality treatment for patients interdisciplinary ECMO therapy has to be regulated in the near future. New concepts for ECMO therapy, e.g. the total artificial lung concept or the long-term treatment of patients with pulmonary hypertension with ECMO need further clinical observation and testing.     

Application of ECMO in multitrauma patients with ARDS as rescue therapy

BACKGROUND: Despite recent advances in critical care management, the mortality of acute respiratory distress syndrome (ARDS) remains high. The final rescue therapy for patients with severe hypoxia refractory to conventional therapy modalities is the extracorporeal gas exchange. METHODS: We report the management of three polytraumatized patients with life-threatening injuries, severe blunt thoracic trauma, and consecutive ARDS treating by extracorporeal membrane oxygenation (ECMO). Two patients suffered a car accident with severe lung contusion and parenychmal bleeding. Bronchial rupture and mediastinal emphysema was found in one of them. Another patient developed ARDS after attempted suicide with multiple fractures together with blunt abdominal and thoracic trauma. RESULTS: All patients were placed on ECMO and could be rapidly stabilized. They were weaned from ECMO after a mean of 114 +/- 27 hours of support without complications, respectively. Mean duration of ICU stay was 37 +/- 23 days. CONCLUSIONS: Quick encouragement of ECMO for the temporary management of gas exchange may increase survival rates in trauma patients with ARDS.     

A complication of ECMO cannula placement resulting in hemodynamic and oxygenation alterations: A case report

Veno-veno extracorporeal membrane oxygenation (VV ECMO) is used as a bridge to recovery in acute respiratory distress syndrome (ARDS) patients who have reversible lung failure. We present a complication of ECMO cannula placement/position resulting in hemodynamic and oxygenation alterations. These demonstrate principles related to the interaction of the VV ECMO circuit and patient cardio-pulmonary physiology. Consideration and comprehension of pulmonary shunt fraction, ECMO cannula recirculation ratio and ECMO blood flow to cardiac output (CO) ratio are central to continuous assessment and diagnosis of cardio-pulmonary changes encountered during management of VV ECMO.     

ECMO in ARDS: a long-term follow-up study regarding pulmonary morphology and function and health-related quality of life

Background: A high survival rate can be achieved in patients with severe acute respiratory distress syndrome (ARDS) using extracorporeal membrane oxygenation (ECMO). The technique and the costs are, however, debated and follow-up studies in survivors are few. The aim of this study was to evaluate long-term pulmonary health after ECMO and severe ARDS.
Methods: Twenty-one long-term survivors of severe ARDS and ECMO were studied in a follow-up program including high-resolution computed tomography (HRCT) of the lungs, extensive pulmonary function tests, pulmonary scintigraphy and the pulmonary disease-specific St George's Respiratory Questionnaire (SGRQ).
Results: The majority of patients had residual lung parenchymal changes on HRCT suggestive of fibrosis, but the extension of morphologic abnormalities was limited and without the typical anterior localization presumed to indicate ventilator-associated lung injury. Pulmonary function tests revealed good restitution with mean values in the lower normal range, while T½ for outwash of inhaled isotope was abnormal in all patients consistent with subclinical obstructivity. Most patients had reduced health-related quality of life (HRQoL), according to the SGRQ, but were stating less respiratory symptoms than conventionally treated ARDS patients in previous studies. The majority were integrated in normal work.
Conclusion: The majority of ECMO-treated ARDS patients have good physical and social functioning. However, lung parenchymal changes on HRCT suggestive of fibrosis and minor pulmonary function abnormalities remain common and can be detected more than 1 year after ECMO. Furthermore, most patients experience a reduction in HRQoL due to the pulmonary sequelae.     

ECLS in Trauma: Practical Application and a Review of Current Status

Extracorporeal life support has evolved considerably over the past two decades. Once considered as salvage or experimental therapy in adults, extracorporeal membrane oxygenation (ECMO) is evolving into a mainstream treatment for adult critical care. This is especially true in trauma and high-risk surgical patients, who have traditionally been excluded from consideration. Several technological advances have made this possible. This includes anticoagulant-bonded circuits, device miniaturization, servo-regulated centrifugal systems, and more efficient oxygenators. Adult ECMO may now be rapidly deployed for severe acute respiratory distress syndrome (ARDS) and cardiogenic shock. Trauma and surgical patients with severe ARDS should be considered for ECMO early in their clinical course to provide optimal lung rest.

     

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a heterogeneous lung disease that is triggered by pulmonary and non-pulmonary pathologies. It predominantly causes hypoxaemic respiratory failure and can lead to significant morbidity and mortality. Although ARDS remains underdiagnosed, 24% of mechanically ventilated patients in intensive care units and 33% of coronavirus disease (COVID-19) patients admitted to the hospital are reported to have ARDS. Despite recent advances in treatment, mortality remains at more than 30% for all ARDS patients and 43% for severe ARDS.The pathophysiology is complex and involves acute pulmonary and systemic inflammation, alveolar oedema, and de-recruitment which lead to ventilation-perfusion mismatch, reduced lung compliance and hypoxaemia. Similarities in the pathophysiology of COVID-19 ARDS outnumber differences from non-COVID-19 ARDS. Inhomogeneous distribution of transpulmonary pressure variation throughout the lungs in ARDS increases the risk of patient self-inflicted lung injury and ventilator-associated lung injury.Stratifying ARDS patients as per Berlin definition can help to recognize ARDS early, identify resource requirements and plan appropriate management. Treating the underlying cause, lung-protective ventilation and supportive care are the mainstays of clinical management. Multiple rescue therapies, novel treatments, and methods of facilitating individualized ventilation have been described but many require further validation; and appropriate patient selection is warranted.     

The advent of ECMO and pumpless extracorporeal lung assist in ARDS—a review

Despite advances in critical care facilities and ventilation therapies Acute Respiratory Distress Syndrome (ARDS) is associated with high mortality rates. The condition can stem from a multitude of causes including pneumonia, septicemia, and trauma ultimately resulting in ARDS. ARDS is characterized by respiratory insufficiency with severe hypoxemia or hypercapnia. The treatment strategy depends on the knowledge of the underlying disease. But lung protective ventilation with adjusted positive end expiratory pressure remains the most effective therapeutic tool despite advances in prone positioning, inhalation of nitric oxide and the use of steroids. Newer modalities including Extracorporeal Membrane Oxygenation (ECMO) and Pumpless Extracorporeal Lung Assist (PECLA) are being increasingly introduced in critical care settings as rescue therapies in patients who fail to respond to conservative measures. We describe here the introduction and advances of both ECMO and ECLA in the management of ARDS.     

Successful extracorporeal membranous oxygenation for a patient with life-threatening transfusion-related acute lung injury

A case of transfusion-related acute lung injury (TRALI) that was successfully treated with extracorporeal membranous oxygenation (ECMO) is reported. A 58-year-old male patient underwent hepatectomy, and pulmonary edema occurred after the administration of fresh-frozen plasma and packed red cells. In the postoperative period, the impaired oxygenation progressively worsened, resulting in life-threatening hypoxemia, despite vigorous treatments. ECMO was therefore applied to the patient as a method of safe emergency support. Aggressive treatments under ECMO led to the successful improvement of the impaired oxygenation. TRALI is recognized as part of acute respiratory distress syndrome (ARDS). As a treatment for ARDS, ECMO does not cure the underlying disease of the lungs, however, with ECMO, TRALI, usually improves within 96 h with respiratory support. ECMO for TRALI-induced lethal hypoxemia is useful for providing time to allow the injured lung to recover. It is suggested that ECMO might be a useful option for the treatment of TRALI-induced, potentially lethal hypoxemia.     

Temporary extracorporeal membrane oxygenation in the treatment of acute traumatic lung injury

PURPOSE: To report two cases of acute life-threatening traumatic lung injury, who required temporary extracorporeal veno-venous membrane oxygenation (ECMO), and airlifting to a level I trauma centre. CLINICAL FEATURES: The first patient suffered a severe motor vehicle accident with prolonged entrapment in the wreckage. After extrication, tracheal intubation, and fluid resuscitation, respiratory therapy failed to result in sufficient ventilation and oxygenation within the first hours after trauma due to severe lung contusion and intraparenychmal bleeding. The second patient was hit by a falling tree and suffered isolated blunt chest trauma. Due to pulmonary contusions and tracheal rupture, subsequent ventilation management was limited by extensive mediastinal emphysema. Both patients were airlifted to a University Hospital and placed on ECMO for four and six days without complications, respectively. After emergency surgery and 21 and 26 days intensive care treatment, both patients were transferred to a general ward, and discharged from the hospital with full recovery. CONCLUSION: These cases demonstrate the role of ECMO in the treatment of traumatic respiratory failure. If ventilatory support strategies fail due to severe lung or airway injury, ECMO may be an option for the temporary management of gas exchange in trauma patients.     

Successful Recovery After Veno-Arterio-Venous Extracorporeal Membrane Oxygenation Immediately Before Liver Transplantation in Multi-Organ Failure Including Acute Respiratory Distress Syndrome: A Case Report

Extracorporeal membrane oxygenation (ECMO) has emerged as an alternative treatment to conventional ventilation maneuvers in the nontransplantation literature to support acute respiratory distress syndrome. However, the role of ECMO in transplant is unclear, and few case reports have described using ECMO pretransplant. We discuss the successful use of veno-arteriovenous ECMO as a bridge therapy to deceased donor liver transplant (LT) in acute respiratory distress syndrome. Because the incidence of severe pulmonary complications resulting in acute respiratory distress syndrome with multiorgan failure is rare before LT, determining the usefulness of ECMO is challenging. However, in acute but reversible respiratory failure and cardiovascular failure, veno-arteriovenous ECMO provides a useful therapeutic option as a bridge for patients awaiting LT and should be considered if available even in multiorgan failure.     

Combination of extracorporeal membrane oxygenation and high-frequency oscillatory ventilation saved a child with severe ARDS after pulmonary resection

We report a case in which a 2-year-old girl who underwent a right middle and lower lung lobectomy for congenital cystic adenomatoid malformation suffered massive bleeding and developed acute respiratory distress syndrome (ARDS) during the operation. She was ventilated with a high level of F_IO₂ (0.75–1.0), PEEP (10–20 cmH₂O), and PIP (33–55 cmH₂O) to maintain SPO₂ (>90%). Following transfer to the ICU, continuous hemodialysis was introduced to reduce excessive blood volume. However, pulmonary oxygenation did not improve, and marked subcutaneous emphysema occurred on postoperative day 3 (POD 3). We introduced venovenous (V-V) extracorporeal membrane oxygenation (ECMO) to rest the lung, and V-V ECMO was changed to right and left atrial ECMO because of unsatisfactory oxygen support on POD 23. A CT scan showed almost the entire lung had collapsed, even though we had administered diuretics, steroids, nitric oxide, sivelestat, and surfactant for ARDS. We applied high-frequency oscillatory ventilation (HFOV) with a mean airway pressure of 20 cmH₂O, frequency of 9.2 Hz, and amplitude of 38 cmH₂O on POD 45. The collapsed lung was then gradually recruited, and pulmonary oxygenation improved (P/F ratio = 434). ECMO was successfully weaned on POD 88. The patient required a tracheostomy, but she was able to function without a ventilator on POD 142. Although HFOV has failed to show a mortality benefit in ARDS patients, the unique lung recruitment by HFOV can be a useful therapeutic option for severe ARDS patients in combination with sufficient lung rest produced by ECMO.