Blood propulsion technology in adult extracorporeal carbon dioxide removal: a scoping review protocol

The claim that roller (peristaltic) pumps cause less haemolysis than centrifugal pumps during extracorporeal carbon dioxide removal (ECCO₂R) is being used in current debate about adult practice. However, the only published quantitative comparison of the two pump types comes from neonatal and paediatric ECMO, mostly in children under 5 kg on venoarterial support. No adult ECCO₂R patient contributes to that estimate. No registered protocol or published review has mapped blood propulsion technology within adult ECCO₂R. This scoping review, conducted according to PRISMA-ScR, will map which blood propulsion technologies have been used in adult ECCO₂R, under which operating conditions, and what has been reported for each about device-related events, circuit lifespan and CO₂ removal performance. Secondary questions address how completely pump type and operating parameters are reported in clinical studies, how haemolysis is defined and ascertained, and what bench and in silico evidence exists within the ECCO₂R flow range (below 500 mL/min and 500–1,500 mL/min). Evidence is handled in separate streams that are never pooled: adult clinical studies; bench and in silico studies; paediatric and neonatal literature, charted only as an external comparator, to document the flow regimen behind the existing claim; post-market surveillance reports from FDA MAUDE and MHRA, used only to describe failure modes. Devices are classified with a pre-specified four-level taxonomy (propulsion principle, architecture, commercial platform, circuit configuration), which is frozen before the search runs. The clinical search contains no pump or haemolysis terms, so studies that do not report their technology are still retrieved and counted. Synthesis is descriptive only. The review will not estimate comparative effects or pool haemolysis rates. Its planned outputs are: an evidence map by technology; a reporting completeness matrix, including a ten-item count and a four-item core set; a table showing how haemolysis was ascertained in each study; a qualitative inventory of failure modes; a map of where evidence is missing across the streams; a proposed minimum reporting set for future ECCO₂R studies. The review does not aim to show that one pump type is safer than another. Its aim is to establish what has actually been documented in adults, and where the gaps are.