A wet-primed extracorporeal membrane oxygenation circuit with hollow-fiber membrane oxygenator maintains adequate function for use during cardiopulmonary resuscitation after 2 weeks on standby*

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Abstract
To assess the durability of wet-preprimed extracorporeal membrane oxygenation (ECMO) circuits for potential use in resuscitation after a 2-wk period of storage. Experimental laboratory study. Tertiary care pediatric cardiac intensive care unit. None. 14 ECMO circuits (polyvinyl chloride and super-Tygon tubing with hollow-fiber oxygenator, Medos Hilite 800LT) were primed with crystalloid under sterile conditions and stored for 0 (control, n = 4), 7 (n = 5) and 14 (n = 5) days and maintained at 8°C on pump at 10 rpm and gas flow at 0.2 L/min. Daily samples were inspected for plasticizers by means of high-performance liquid chromatography and for microorganisms by culture and polymerase chain reaction techniques. After storage, the oxygenators were primed with red blood cells (hemoglobin, 12 g/dL) and tested in vitro with a deoxygenator according to Association for Advancement of Medical Instrumentation standards. Oxygen and CO2 transfer rates were calculated by standard formulae at maximum blood flow (800 mL/min) and maximum sweep gas flow (1.6 L/min). Oxygen transfer was linearly related to venous oxygen saturation, increasing by 11 mL/min for each 10% decrease in venous oxygen saturation. Estimated oxygen transfer at venous oxygen saturation of 60% was 45.8 mL/min (95% confidence interval [CI], 43.5–48.1) for controls, 51.0 mL/min (95% CI, 48.9–53.2) for 7-day oxygenators, and 49.0 mL/min (95% CI, 47.8–50.1) for 14-day oxygenators. CO2 transfer declined to 29.2 mL/min at 14 days of storage, a mean fall of 11.5 mL/min (95% CI, 4.2–18.7) in comparison with 7-day storage. All circuits were free from microbes/microbial DNA. Plasticizer levels fell below the lower limit of detection (0.003 μg/mL) at 7 and 14 days. A wet-preprimed ECMO circuit with hollow-fiber membrane oxygenator can be stored for up to 2 wks with adequately preserved function if prepared appropriately. These data may improve safe access to rapid-response ECMO support.