BLENDER Trial Findings Need Long-term Outcomes Blended into Clinical Practice
Will emerging evidence and clinical research reshape oxygen management in VA-ECMO? A key study leading this shift could be the BLENDER trial, recently published in Intensive Care Medicine, which challenges the longstanding caution against hyperoxemia in critically ill patients. My article looks at the BLENDER trial and contrasts it with other research from China on hyperoxia, including insights from the ELSO Red Book and the ELSO Specialist Training Manual.
You can access the full Blender Trial here.
BLENDER Trial at a Glance:
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Design and Scope: The BLENDER trial was a multicentre, randomized controlled study conducted across 12 Australian hospitals involving 300 adult VA-ECMO patients. The study compared outcomes between two groups: those managed with conservative oxygen targets (SaO2 92–96%) and those with more liberal targets (SaO2 97–100%). *1.
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Key Findings: Surprisingly, there was no significant difference in primary outcomes, such as ICU-free days at 28 days, nor secondary outcomes, like mortality at 60 days and long-term functional status at six months_. However, the conservative group experienced more protocol deviations, indicating potential challenges in maintaining lower saturation levels consistently *_1.
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Implications: The findings question the assumption that mild hyperoxemia is inherently harmful in the acute setting of VA-ECMO *1.
Harmful Effects of Hyperoxia in Recent Literature:
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Gut Health and Systemic Inflammation: Recent studies underscore the harmful impacts of hyperoxia on the gut. Excessive oxygen levels can disrupt the gut microbiome, leading to dysbiosis, increased gut permeability, and systemic endotoxemia. These changes can worsen inflammation and contribute to poor outcomes in critically ill patients *2,3.
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Reactive Oxygen Species (ROS) and Organ Damage: Hyperoxia is associated with the overproduction of ROS, which causes oxidative stress and tissue damage in organs such as the lungs and gut, potentially leading to increased mortality *2,3.
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VA-ECMO Specific Risks: Studies indicate that hyperoxia in VA-ECMO, especially with peripheral cannulation, can result in localized hyperoxic injury to organs like the gut. The targeted delivery of supplemental oxygen, although often essential, can have adverse effects on the gastrointestinal tract. This focused oxygen exposure may damage the villi—finger-like projections in the small intestine that are crucial for nutrient absorption. It can also compromise the integrity of the intestinal barrier, which serves as a defense against harmful substances entering the bloodstream. Furthermore, this oxygen exposure can alter the gut microbiome, promoting the growth of oxygen-tolerant, potentially pathogenic microbes while reducing beneficial, oxygen-intolerant species. *2,3,.
ELSO Red Book and ECMO Training Manual Insights:
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ELSO Red Book: Recommends careful oxygen management to mitigate the risks of hyperoxia-related complications, aligning with research that connects excessive oxygen levels with increased mortality and poorer neurological outcomes *4.
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ECMO Specialist Training Manual: Emphasizes maintaining balanced oxygenation levels to avoid the adverse effects of hyperoxia while ensuring adequate patient oxygenation *5.
Comparing the BLENDER Trial and Current Literature:
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Short-Term vs. Long-Term Outcomes: The BLENDER trial’s finding that liberal oxygen targets did not lead to worse short-term outcomes is noteworthy *1. However, recent studies highlight potential long-term risks associated with hyperoxia, such as chronic inflammation and organ health issues 2,3. This discrepancy underscores the need for further studies to evaluate long-term impacts and guide practice.
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Clinical Application: While the BLENDER trial supports flexibility in oxygen management, caution remains essential. ELSO guidelines and the broader literature emphasize avoiding hyperoxia to minimize risks, particularly in patients susceptible to complications like gut injury and systemic inflammation *2,4,5.
Conclusion:
The BLENDER trial challenges traditional beliefs and may encourage a more flexible approach to oxygen management in VA-ECMO. However, findings from recent research and established ELSO guidelines emphasize the importance of individualized care and monitoring for hyperoxia-related complications, especially over the long term. Striking a balance between immediate clinical needs and patient safety is crucial as we grow our understanding of oxygen therapy in ECMO.
What are your thoughts on oxygen management in pVA-ECMO? How do the BLENDER trial and emerging research findings influence your practice? Share your insights so we can learn together.
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ELSO Red Book: MacLaren, G., et al. (2022). Extracorporeal Life Support: The ELSO Red Book, 6th Edition. Extracorporeal Life Support Organization.
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ECMO Specialist Training Manual: Brogan, T.V., et al. (2018). ECMO Specialist Training Manual, 4th Edition. Extracorporeal Life Support Organization.
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Acknowledgments:
Here is a list of tools and resources that assisted in creating this article and others. I developed three custom GPTs for specialized research: AI ECMO Expert, ECMO Specialist Handover Practice, and Micro Definitions (MD-GPT). These tools were instrumental in gathering and analyzing information from key sources.
Special thanks to the AI platforms and tools that facilitated this research:
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GPT-4o/o1, Claude 3.5 Sonnet/Opus, Perplexity
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Grammarly for editorial and proofreading assistance
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Leonardo AI, DALL-E3 AI Image Generator, Microsoft Designer, and Adobe Express for generating images and visual content