Sterility and performance of open and closed extracorporeal circuits after long-term dry-wet setups

Abstract

<jats:sec><jats:title>Background:</jats:title><jats:p> The timeframe for safely using previously setup dry, crystalloid, and blood-primed extracorporeal circuits has long been debated. This study was undertaken to determine a safe deviation from standardized recommendations. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Open (cardiopulmonary bypass) circuits and closed extracorporeal membrane oxygenation circuits were setup dry for up to 60 days and wet primed for up to 6 weeks with one control inoculated with Escherichia coli. Open circuits were cultured daily, closed circuits weekly. Circuits were primed with blood, albumin, heparin, NaHCO<jats:sub>3</jats:sub>, and CaCl<jats:sub>2</jats:sub>. Baseline pCO<jats:sub>2</jats:sub>, pO<jats:sub>2</jats:sub>, hemoglobin, lactate dehydrogenase, and plasma free hemoglobin were measured. Circuits were recirculated at a blood flow of 6 Liters/minute with a sweep gas of 1 Liter/minute at 100% FiO<jats:sub>2</jats:sub> for 1 minute. Post oxygenator blood gases were collected at 8-, 16-, and 24-hour intervals. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> There was no observed compromise to the sterility of the circuits and no clinically significant gas exchange abnormalities observed over the duration of the study period. Statistical significance (p &lt; 0.01) was seen in free hemoglobin and lactate dehydrogenase levels, most significant in between the 16- and 24-hour time point in the closed systems intentionally inoculated with E. coli. </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> Open and closed circuits can be safely setup dry for up to 60 days. Open, wet-primed circuits can be used safely up to 5 days. Closed, wet-primed circuits can be used safely up to 6 weeks. Blood-primed circuits can be safely run up to 16 hours prior to patient use but should be validated in a randomized clinical study. </jats:p></jats:sec>

Sterility and oxygenator function in pre-primed extracorporeal membrane oxygenation: A prospective clinical study

“…Experimental studies have demonstrated that bacteria can propagate and persist in ECMO circuits for extended periods when intentionally inoculated. 10 , 12 However, the crystalloid priming medium used in clinical practice lacks cellular substrates, and the room temperature storage of ECMO circuits may result in lower bacterial growth rates compared to body fluids, potentially posing challenges for sterility testing. Our study employed a sensitive culturing method specifically designed for extracorporeal fluids, involving extended incubation times.…”

“…The scientific basis for pre-primed ECMO is based on a limited number of experimental studies, each involving a small number of ECMO circuits with wet pre-primed times ranging from 7 to 65 days. 10 , 11 , 12 , 13 , 14 , 15 One study incorporated a dry set up phase prior to wet priming. 10 Although no bacterial growth was observed in any of the circuits, it is important to note that the reported incubation times, during which bacteria and fungi can proliferate, were only two or three days when mentioned, while the general standard for considering cultures negative requires an incubation period of at least 5 days.…”

“… 10 , 11 , 12 , 13 , 14 , 15 One study incorporated a dry set up phase prior to wet priming. 10 Although no bacterial growth was observed in any of the circuits, it is important to note that the reported incubation times, during which bacteria and fungi can proliferate, were only two or three days when mentioned, while the general standard for considering cultures negative requires an incubation period of at least 5 days. 16 In two of the studies, a few ECMO circles were wet-primed and inoculated with Escherichia coli , resulting in the persistence of bacteria within the circuits for an extended period.…”

“…Three of the experimental studies assessed oxygenator function after wet priming and observed decreased oxygenation or carbon dioxide (CO 2 ) removal from the test solution during short test periods. 10 , 11 , 15 …”

Starting and Sustaining an Extracorporeal Membrane Oxygenation Program

“…24 Closed, wet-primed circuits can be used safely up to 6 weeks. 25 Coordinating availability and usage of disposables between ECMO centers can be an effective strategy for a new ECMO center to optimize supply chain management, reduce waste, and mobilize resources at the point of care supplies are needed most. 26 Table 3 lists specifications for physical requirements for facilities, equipment, and supplies needed.…”