When doctors use a special heart-lung machine called VA-ECMO to help patients with severe heart failure, their bodies go through big changes in how they process nutrients. Researchers watched 46 patients over 5 days and found that important proteins in the blood dropped quickly in the first 2 days, and muscle measurements got smaller over time. This study shows that patients on these machines need special attention to their nutrition right away to help them recover better. The findings suggest doctors should start watching nutrition levels and giving nutritional support as soon as patients get connected to the machine.

The Quick Take

  • What they studied: How a patient’s nutrition and body composition change during the first 5 days after being connected to a heart-lung support machine (VA-ECMO)
  • Who participated: 46 adults (average age 50) who were in severe heart failure and needed emergency support from a mechanical heart-lung machine between 2022 and 2024
  • Key finding: Protein levels in the blood dropped significantly within the first 48 hours, and muscle measurements decreased over the 5-day period. Age and high cholesterol affected how quickly these changes happened.
  • What it means for you: If you or a loved one needs this type of heart support, early nutrition monitoring and support may help with recovery. However, this is a small study and more research is needed to confirm the best approaches.

The Research Details

This was a prospective observational study, which means researchers followed patients forward in time and carefully recorded what happened to them. They enrolled 46 adults who were receiving VA-ECMO support (a machine that takes over the work of a failing heart and lungs) and measured their nutritional markers—like protein levels in blood, muscle thickness, and arm measurements—every day for 5 days.

The researchers collected information about each patient’s age, medical history, and various blood markers that show how the body is using nutrients. They used statistical analysis to look for patterns in how these measurements changed over time and to identify which patient characteristics (like age or cholesterol levels) influenced these changes.

This type of study is valuable because it captures real-world changes as they happen, rather than trying to recreate the situation in a lab. However, because it’s observational rather than experimental, researchers can identify patterns but can’t prove that the machine itself directly causes the changes.

Understanding what happens to nutrition during the critical first days of heart-lung machine support is important because it helps doctors know when and how to intervene. If we know that protein levels drop quickly, doctors can monitor this closely and provide nutritional support sooner. This research approach is appropriate because these patients are in critical condition and can’t be randomly assigned to different treatments—researchers can only observe what naturally happens.

This study has several strengths: it prospectively followed patients (collecting data as events happened rather than looking back), it measured multiple nutritional markers, and it used appropriate statistical methods. However, the sample size is relatively small (46 patients), which means the findings may not apply to all patients. The study was conducted at specific hospitals during a specific time period, so results might differ in other settings. The researchers acknowledge that more validation is needed before making firm clinical recommendations.

What the Results Show

The most striking finding was a rapid drop in serum albumin (a key protein in blood) within the first 48 hours. On average, albumin levels fell by about 5.7 units, which was statistically significant. This happened in nearly all patients and was one of the earliest signs of nutritional stress.

Beyond the first 2 days, researchers observed progressive decreases in muscle measurements. Triceps skinfold thickness (a measure of fat and muscle under the skin) and mid-upper arm circumference (the size of the upper arm) both decreased significantly from day 2 through day 5. These changes suggest that patients’ bodies were breaking down muscle tissue during this critical period.

The study also found that certain patient characteristics influenced how quickly these changes occurred. Age and hyperlipidemia (high cholesterol) were independent factors affecting albumin levels. This means that older patients or those with high cholesterol experienced different nutritional changes than younger, healthier patients.

The neutrophil count (a type of white blood cell) and the prognostic nutrition index (a calculated score combining protein and immune markers) also showed significant changes over the 5-day period, indicating broader metabolic stress in the body.

Beyond the primary findings, the research revealed that nutritional stress was not uniform across all patients. The variability in how quickly albumin dropped and how much muscle was lost suggests that individual factors matter. Some patients experienced more dramatic changes than others, which could help doctors identify who needs the most aggressive nutritional support. The combination of multiple changing markers (albumin, muscle measurements, immune cells) suggests that the body experiences a coordinated stress response to being on the heart-lung machine.

Previous research has shown that critical illness in general causes rapid protein breakdown and muscle loss, but this is one of the first studies to specifically track these changes during VA-ECMO support in the crucial first 5 days. The findings align with what we know about how the body responds to severe stress, but they provide specific timing and measurements that can guide clinical practice. The early albumin drop (within 48 hours) is particularly important because it suggests a narrow window for intervention.

The study included only 46 patients, which is a relatively small number. This means the findings might not apply to all patients receiving this treatment. The study was conducted at specific hospitals, so results might be different in other medical centers with different practices. The researchers could only observe what happened naturally—they couldn’t test whether giving extra nutrition earlier would prevent these changes. Additionally, the study didn’t follow patients beyond 5 days, so we don’t know if these early changes predict long-term outcomes. Finally, the study didn’t include information about what nutritional support patients actually received, so we can’t determine if certain interventions were more helpful than others.

The Bottom Line

Based on this research, doctors should: (1) Monitor protein levels (albumin) closely starting immediately when patients begin VA-ECMO support, with special attention in the first 48 hours; (2) Assess muscle status using measurements like arm circumference and skinfold thickness; (3) Consider early nutritional intervention, especially for older patients or those with high cholesterol; (4) Develop individualized nutrition plans rather than one-size-fits-all approaches. However, these are preliminary recommendations based on a small study, and more research is needed to determine the best specific interventions.

This research is most relevant to: (1) Cardiologists and critical care doctors who manage patients on heart-lung machines; (2) Nutritionists and dietitians working in intensive care units; (3) Patients and families facing VA-ECMO support who want to understand what to expect; (4) Hospital administrators developing protocols for critical care. This research is NOT a guide for general nutrition advice for healthy people or those with mild heart conditions.

The critical changes identified in this study happen very quickly—within the first 2 days for protein levels and over the first 5 days for muscle measurements. This means interventions would need to start immediately upon beginning VA-ECMO support to be effective. Long-term benefits of early nutritional support would likely take weeks to months to become apparent in patient recovery and outcomes.

Want to Apply This Research?

  • For patients or caregivers using a health app: Track daily weight, arm circumference measurements (if able), and appetite/food intake during the first week of heart-lung machine support. Note any changes in energy levels or ability to eat. This data can help medical teams identify trends and adjust nutrition support.
  • Work with your medical team to: (1) Eat small, frequent meals if you’re able to eat orally; (2) Prioritize protein-rich foods (eggs, yogurt, chicken, fish) when cleared by your doctor; (3) Keep a simple food diary showing what you eat and how you feel; (4) Ask your doctor or nutritionist about supplements if eating is difficult.
  • Long-term tracking should include: (1) Weekly weight checks after leaving the hospital; (2) Gradual return to normal eating patterns with guidance from a nutritionist; (3) Monitoring energy levels and ability to do daily activities; (4) Follow-up lab work to check protein and nutritional markers at 2 weeks, 1 month, and 3 months post-discharge. Share this information with your medical team to adjust your nutrition plan as needed.

This research describes what happens to nutrition during heart-lung machine support but does not provide medical advice. If you or a loved one is receiving or considering VA-ECMO support, discuss nutrition management with your medical team, including your cardiologist and hospital nutritionist. The findings are based on a small study of 46 patients and should not be used to make individual medical decisions without consulting qualified healthcare providers. Always follow your doctor’s specific recommendations for your situation.