As the research and evidence in ECMO continues to change and evolve, hospitals with ECMO programs must stay updated on best practices to optimize patient care. One persistent question concerns whether to prone patients while on venovenous extracorporeal membrane oxygenation (VV-ECMO).

Understanding Prone Positioning in ARDS

Prone positioning—turning patients from their back to their stomach—has become a standard intervention for moderate to severe Acute Respiratory Distress Syndrome (ARDS). The physiological benefits include more even distribution of ventilation, improved ventilation-perfusion matching, and better drainage of secretions.

 

Most of the research on prone positioning with ECMO involves VV-ECMO rather than VA-ECMO (venoarterial extracorporeal membrane oxygenation). This is because VV-ECMO is primarily used for respiratory failure like ARDS, where prone positioning already shows benefits in non-ECMO patients. Additionally, VA-ECMO, which supports heart function, typically involves arterial cannulas that pose greater risks during position changes, and the underlying conditions requiring VA-ECMO often don’t benefit from the lung-specific advantages that prone positioning provides.

Mixed Signals in the Evidence Landscape

While prone positioning has demonstrated clear mortality benefits in non-ECMO ARDS patients, its role during ECMO support remains less defined, with studies showing conflicting results.

A 2022 pooled analysis published in Critical Care examined data from 889 patients across five European studies. After statistical adjustment, the researchers found that prone positioning during ECMO was not associated with a decrease in ICU mortality. However, when matched patients were compared, those in the prone position group had an 8.4% lower absolute ICU mortality rate (39.6% vs 48.0%), though this difference didn’t quite reach statistical significance.

One encouraging finding from this analysis was the safety profile: among hundreds of prone positioning sessions, there were no reported cases of accidental extubation or dislodgement of ECMO cannulas, addressing one of the primary concerns about prone positioning during ECMO.

In exploratory analyses, certain patient groups demonstrated a stronger association with prone positioning and decreased mortality, particularly younger patients, non-obese patients, those with more severe illness, and those with shorter durations of mechanical ventilation before ECMO.

Randomized Evidence: The PRONECMO Trial

A major limitation of the pooled analysis was its reliance on observational studies rather than randomized trials. However, the more recent PRONECMO randomized clinical trial published in JAMA provides more definitive data.

This multicenter study included 170 patients (primarily with COVID-19-related ARDS) and found no significant difference in successful ECMO weaning rates between prone and supine positioning groups (both 44%). Similarly, there were no significant differences in ECMO duration or 90-day mortality. In addition, no serious adverse events occurred during proning maneuvers, which provides evidence that prone positioning is safe when performed by experienced ECMO teams.

Practical Considerations for ECMO Programs

For hospitals with ECMO programs, several practical considerations emerge:

1. Safety First: The evidence consistently shows that prone positioning during ECMO can be performed safely with properly trained teams and clear protocols.
2. Individualized Approach: Until more definitive evidence emerges, an individualized approach to prone positioning during ECMO may be most appropriate, potentially focusing on patient groups that showed greater benefit in subgroup analyses.
3. Resource Allocation: Prone positioning during ECMO requires additional staffing resources, making it a more labor-intensive maneuver that requires careful planning and coordination.

To Prone or Not To Prone?

The “to prone or not to prone” question during ECMO support continues to spark debate among critical care teams. While the current evidence doesn’t strongly favor routine prone positioning for all ECMO patients, it does suggest the maneuver can be performed safely and may benefit specific patient populations. Ongoing research will likely provide more clarity in the coming years.

At Innovative ECMO Concepts, we believe in staying abreast of emerging evidence-based medicine and merging it with practical clinical judgment. As research in this field continues to mature and evolve, we encourage programs to develop thoughtful protocols that consider both the potential benefits of prone positioning and the specific characteristics of individual patients.

Even if selectively applied, the ability to safely perform these positioning maneuvers is valuable and builds institutional expertise. In addition, by staying informed about emerging research and sharing experiences across centers, the ECMO community can continue to research and refine best practices for this complex patient population.