Comparison of the novel membrane-based carbon dioxide filter memsorb™ with a chemical granulate absorbent using a high-fidelity lung simulator: a prospective randomized in vitro trial.

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

Methods: We used an in vitro lung simulator (DUCt) to control CO 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 or 2 L·min, completing three trials for each FGF for either memsorb or CGA. The EtCO and FCO levels were recorded for 30 min in each setting.

Results: EtCO was comparable between the groups with 2 L·min FGF over the observation period. FCO was significantly higher in the memsorb group during the trial (2 L·min; 3.9 mm Hg; 95% CI, 4.4 to 3.3; P < 0.001). EtCO with 0.5 L·min 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 FGF, FCO 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).

Discussion: CO was successfully removed from the anesthesia circuit. FCO 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.