Comparison of the novel membrane-based carbon dioxide filter memsorb™ with a chemical granulate absorbent using a...

Memsorb™ is a novel device for carbon dioxide (CO₂) removal from anesthesia circuits via a semipermeable polymeric membrane. We evaluated the performance of the memsorb device for the removal of CO₂ in an Aisys™ CS² machine and compared it with a standard chemical granulate absorber (CGA) using a high-fidelity lung simulator.

We used an in vitro lung simulator (DUCt) to control CO₂ release by imitating alveolar gas exchange. The ventilator settings were identical for all measurements. The fresh gas flow (FGF) was randomized to either 0.5 L·min^-1 or 2 L·min^-1, completing three trials for each FGF for either memsorb or CGA. The EtCO₂ and F_ICO₂ levels were recorded for 30 min in each setting.

EtCO₂ was comparable between the groups with 2 L·min^-1 FGF over the observation period. F_ICO₂ was significantly higher in the memsorb group during the trial (2 L·min^-1; 3.9 mm Hg; 95% CI, 4.4 to 3.3; P < 0.001). EtCO₂ with 0.5 L·min^-1 FGF was higher with memsorb than with CGA over the observation period (3.7 mm Hg; 95% CI, 2.7 to 4.7; P = 0.004). With 0.5 L·min^-1 FGF, F_ICO₂ was significantly higher in the memsorb group compared with CGA over the whole observation period (6 mm Hg; 95% CI, 6.4 to 5.5; P < 0.001).

CO₂ was successfully removed from the anesthesia circuit. F_ICO₂ was significantly higher with memsorb throughout the observation period. Nevertheless, the clinical impact of these observations remains unclear. Further clinical trials are required to determine the utility of the novel device.