Arens 2026 — Standardization of in vitro evaluation of ECLS devices

International multidisciplinary group of ECLS experts; recommendations and standardised criteria for in vitro device testing according to international norms, so that results from different research groups become comparable.

What Chapter 27 takes from it:

• ISO 7199 specifies an inlet condition of SO2 65 ± 5%, at haemoglobin 120 g/L — the third and lowest of the three standardised inlet saturations now recorded in this book for rated-flow testing (against 70% in the ELSO Red Book and ISCCM Manual and 75% in the practical-guide textbook and, internally, in Bartlett 2020).
• The minimum physiological requirement: an oxygenator should exchange at least 50 mL of oxygen per litre of blood, derived as 1.34 mL/g × 120 g/L × (95% − 65%) plus the dissolved term.
• The corresponding carbon dioxide minimum of 40 mL per litre for an adult on a mixed diet, from a respiratory quotient of 0.8; 50 mL/L in neonates and children on a predominantly carbohydrate diet with a quotient near 1.
• Gas exchange should be reported as millilitres of gas per litre of blood across a range of blood flow rates, which is independent of device type or size and allows oxygenators to be compared directly.
• Gas exchange testing must use whole blood, because the oxygen bound to haemoglobin far exceeds the dissolved fraction; stored blood must be evaluated for red cell age effects on binding and release.

Why it matters to this book: it is the document that makes the rated-flow discrepancy consequential — two devices tested at different inlet saturations are not comparable, and a bedside clinician comparing an observed outlet saturation to a printed rated flow is making exactly that comparison.

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