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Extracorporeal support for respiratory failure is growing rapidly; critical care physicians will be required to make informed decisions about the application of extracorporeal gas exchange.
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Venovenous extracorporeal gas exchange for severe respiratory failure may be used to rescue patients with severe acute respiratory distress syndrome (ARDS) who are not responding to lung protective ventilation and optimal critical care therapies.
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Extracorporeal carbon dioxide removal is a promising emerging
Extracorporeal Gas Exchange: The Expanding Role of Extracorporeal Support in Respiratory Failure
Section snippets
Key points
Extracorporeal support terminology
Extracorporeal membrane oxygenation (ECMO) is a temporary extracorporeal life support system (ECLS) to support a failing cardiopulmonary system in the setting of severe critical illness requiring mechanical ventilator support. ECMO may be implemented via venoarterial (VA-ECMO) or venovenous (VV-ECMO) approaches to exchange carbon dioxide (CO2) and oxygen under high blood flow conditions (up to 7 L/min) requiring large canulas (20–31 Fr)4 (Table 1). Extracorporeal CO2 removal (ECCO2R)
Historical context and current evidence base for the use extracorporeal gas exchange
ECMO and ECCO2R advanced from bench-side experiments to clinical practice in the late 1960s and early 1970s.9, 10 However, 4 decades of early trials implementing ECMO for critically ill adults showed a lack of benefit despite its theoretic intentions.11, 12 Since these early trials, technology and the management of respiratory failure in intensive care units have evolved greatly. Critical care medicine now uses multidisciplinary teams, evidence-based protocols, efficient care bundles, lung
Extracorporeal Carbon Dioxide Removal for Acute Respiratory Distress Syndrome
Much of the early work related to ECCO2R involved patients with ARDS. In general, most studies showed improvement in Paco2 and accommodated low lung volume ventilation. A recent excellent review by Schmidt and colleagues13 provides a comprehensive review of ECCO2R for ARDS (Box 3). The concept of using extracorporeal support to facilitate CO2 removal as an adjunct to positive pressure ventilation was introduced and investigated as early as 1978 by Gattinoni and colleagues.20
The SUPERNOVA trial
Permissive hypercapnia in severe respiratory failure and its physiologic effects: rationale for extracorporeal carbon dioxide removal
The National Institutes of Health ARDS Network (ARDSnet) found that hypercapnic acidosis is something to tolerate for the mortality benefits from lung-protective ventilation using low-tidal-volume, low-pressure mechanical ventilation strategies.22 Low-tidal-volume ventilation may result in decreased respiratory compliance resulting in hypercapnic acidosis. Although there have been suggestions that hypercapnia may mitigate lung injury and inflammation in ARDS, the evidence is conflicted, and
Extracorporeal gas exchange may facilitate lung protective ventilation; rationale for carbon dioxide removal
Significant reductions in pH caused by hypercapnia may force intensivists to abandon low-tidal-volume ventilation strategies.27 Extracorporeal gas exchange offers the opportunity to continue low-tidal-volume ventilation and maintain pH, therefore enhancing lung protective ventilation and avoiding the complications of hypercapnia.
Batchinsky and colleagues28 have professed the role of extracorporeal gas exchange as a form of “respiratory dialysis” to facilitate lung protective ventilation.
Indications for extracorporeal life support in respiratory failure and patient selection
Indications and patient selection for use of VV ECMO or ECCO2R are developed by each institution and variation exists. The Extracorporeal Life Support Organization (ELSO) has published expert guidelines informed by available evidence, which are listed in Box 4.
Once the indications for extracorporeal support have been met, patient selection may be further guided by the list in Box 5.
Different perspectives exist regarding the definition of failure of optimal treatment. The inability to achieve
Technical aspects: cannula, circuit, pump, gas exchange membrane
An extracorporeal system requires at least 4 components: a cannula or cannulas, tubing for the circuit, usually a pump, and a gas exchange device. Additional components include a heater/cooler, pressure monitor, continuous blood gas analyzer, and flow meter. Some of the newer devices have pressure, temperature, blood gas analyzers, and flow meters included into their system already.
Challenges and adverse effects of extracorporeal gas exchange
Successful implementation of extracorporeal gas exchange in critically ill patients requires a specialized multidisciplinary team. A facility with appropriate resources and experience with ECLS is recommended. In addition, staff must be experienced and trained in both the insertion and the setup of devices and in recognizing and managing complications. Finally, quality assurance and improvement policies should be implemented. The coordination of care and institutional requirements for
Summary
The revival of extracorporeal support over the last decade suggests an impending paradigm shift in the management of adult respiratory failure. If the EOLIA trial reports a survival benefit for ECMO, the use of ECMO will continue to expand in severe ARDS. Several RCTs examining the use of ECCO2R in non-ARDS respiratory failure are in progress. Based on the epidemiology of respiratory failure and the possible use of extracorporeal support in a preventative and preemptive fashion, the use of
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Cited by (5)
Transport While on Extracorporeal Membrane Oxygenation Support
2017, Critical Care ClinicsCitation Excerpt :Vision is the first of the body’s special senses to be affected by lack of oxygen and impairment can be detected at altitudes of 5000 feet at nighttime and 10,000 feet during the day.28 Extracorporeal support is a highly specialized treatment modality with complications such as catheter site hemorrhage, surgical site hemorrhage, pneumothorax, and catheter-related infection well-documented in the literature.34 In addition to the host of complications pertaining to extracorporeal support, the inherent nature of transporting such a critically ill patient on multiple different life support devices adds an additional layer of complexity and opportunity for error or adverse events.
On the horizon: Extracorporeal carbon dioxide removal
2022, Cleveland Clinic Journal of MedicineAssessment and management of acute respiratory distress in the ICU
2018, Surgical Critical Care Therapy: A Clinically Oriented Practical ApproachWhat Can We Apply to Manage Acute Exacerbation of Chronic Obstructive Pulmonary Disease with Acute Respiratory Failure?
2018, Tuberculosis and Respiratory DiseasesPrinciples of pulmonary medicine
2018, Principles of Pulmonary Medicine
Neither author has any disclosures or conflicts of interest.