Extracorporeal membrane oxygenation (ECMO) has become an increasingly important life-support therapy for patients with severe respiratory failure who do not respond to conventional treatments. The article titled “Evidence-Based Guidelines for the Use of Extracorporeal Membrane Oxygenation in Australia and New Zealand Using GRADE Methodology Series Part 1: Venovenous Extracorporeal Membrane Oxygenation (VV ECMO) Indications and Management” presents comprehensive clinical practice guidelines aimed at standardizing and improving ECMO use in adult patients across Australia and New Zealand. These guidelines were developed by a multidisciplinary panel of clinicians, researchers, and patient representatives using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) framework to evaluate evidence quality and formulate recommendations.
VV ECMO is a specialized form of extracorporeal life support designed to provide oxygenation and carbon dioxide removal for patients with severe respiratory failure. The technology evolved from cardiopulmonary bypass systems and functions by diverting blood outside the body through an oxygenator before returning it to the circulation. This allows the lungs to rest while clinicians implement lung-protective ventilation strategies, thereby reducing ventilator-induced lung injury (VILI). The therapy is particularly relevant in cases of severe acute respiratory distress syndrome (ARDS), where mortality rates can remain as high as 40 percent despite optimal conventional treatment.
Despite its potential benefits, ECMO remains an invasive and resource-intensive therapy. Complications may include bleeding, neurological injury, renal failure, and long-term functional impairment. Registry data cited in the guideline show that approximately two-thirds of ECMO survivors may experience moderate-to-severe disability six months after treatment, with many unable to return to work. These risks highlight the importance of careful patient selection and evidence-based protocols to ensure that ECMO is used appropriately and effectively.
The guideline addresses four major clinical questions related to VV ECMO. These include indications for ECMO in severe hypoxic respiratory failure, use in hypercapnic respiratory failure, the role of prone positioning during ECMO, and optimal mechanical ventilation strategies while patients are supported by ECMO. These topics are summarized in Table 1 on page 3, which outlines the outcomes evaluated for each question, including mortality, quality of life, neurological injury, hospital length of stay, and cost considerations.
For patients with severe hypoxic respiratory failure—most commonly associated with ARDS—the guideline suggests the use of VV ECMO in addition to standard care when conventional treatments fail. Evidence from randomized controlled trials such as the CESAR and EOLIA trials indicates that ECMO can reduce short-term mortality. A pooled analysis of 429 patients from two major trials showed a significant reduction in 28-day mortality and a trend toward improved 90-day survival. These findings support a conditional recommendation for ECMO in patients meeting specific criteria.
However, the certainty of evidence remains limited due to uncertainties surrounding long-term outcomes and patient quality of life. While some studies suggest improvements in health-related quality of life and psychological outcomes among survivors, evidence quality ranges from low to very low. Additionally, ECMO tends to increase hospital length of stay by approximately two weeks compared with conventional care. Despite these limitations, cost-effectiveness analyses indicate that ECMO may still be economically acceptable, with an estimated cost of approximately AUD 36,000 per quality-adjusted life year gained.
The guideline also discusses patient selection criteria for ECMO initiation. As outlined in Table 3 on page 6, patients should typically have severe oxygenation failure despite optimized ventilation strategies, including high inspired oxygen levels, appropriate positive end-expiratory pressure, prone positioning, and neuromuscular blockade. Additionally, mechanical ventilation should usually have been in place for fewer than seven days before ECMO initiation. These criteria help ensure that ECMO is reserved for patients most likely to benefit from the therapy.
For hypercapnic respiratory failure, such as severe asthma or exacerbations of chronic obstructive pulmonary disease (COPD), the guideline finds insufficient evidence to recommend ECMO routinely. No randomized controlled trials directly compare ECMO with conventional treatment in these populations. While observational studies suggest possible benefits, the evidence is too limited and heterogeneous to support a clear recommendation.
Another question addressed in the guideline is whether patients receiving VV ECMO for ARDS should be routinely placed in the prone position. Prone positioning has long been shown to improve outcomes in ARDS patients receiving mechanical ventilation. However, performing this maneuver in ECMO patients is technically complex and carries risks such as cannula displacement and circuit complications. A meta-analysis including more than 1,400 patients suggested a potential mortality benefit, but the only randomized trial on this topic did not confirm a significant effect. As a result, the guideline issues a conditional recommendation against routine proning during ECMO due to limited evidence and practical challenges.
Mechanical ventilation strategies during ECMO represent another important clinical consideration. ECMO allows clinicians to reduce ventilator pressures and tidal volumes to minimize lung injury. However, research comparing specific ventilation strategies remains limited. Observational studies suggest that lower driving pressures during ECMO are associated with improved survival, supporting the concept of “lung-protective” or “lung-rest” ventilation. The guideline therefore recommends minimizing ventilator parameters such as tidal volume, driving pressure, and mechanical power while patients are supported by ECMO.
Finally, the authors highlight several areas where further research is urgently needed. These include improved methods for predicting which patients will benefit most from ECMO, better understanding of long-term outcomes, and randomized trials comparing ventilation strategies during ECMO. The guideline also emphasizes the importance of standardizing outcome reporting to better evaluate patient-centered outcomes such as functional recovery and quality of life.
In conclusion, these guidelines represent a significant effort to synthesize current evidence and provide practical recommendations for ECMO use in adult respiratory failure. While VV ECMO can improve survival in carefully selected patients with severe hypoxic respiratory failure, it remains a complex therapy with substantial risks and costs. Continued research and collaborative international efforts will be essential to refine patient selection, optimize management strategies, and improve outcomes for critically ill patients requiring ECMO support.
