Comparative efficacy of four different prefilled CO2 absorbent brands in clinical practice

Abstract Background Evidence regarding CO 2 absorbent performance in real clinical settings is limited. This study compared the CO 2 absorption capacity of four pre-filled CO 2 absorbent brands using two different anesthesia machines in clinical practice. Methods This single-center retrospective study included 3,401 surgical cases who received general anesthesia from November 2022 to January 2024. Four CO 2 absorbents—AMSORB ® Plus, SpiraLith ® , CLIC Drägersorb ® Absorber 800 + , and Drägersorb ® Free—were used in GE Avance and Dräger Primus anesthesia machines. The primary outcome was CO 2 absorption capacity, calculated based on the estimated CO 2 consumption for each patient per canister. Secondary outcomes included total number of surgical cases, cumulative anesthesia time and capacity until inspired CO 2 partial pressure (PiCO 2 ) reached 5 mmHg, as well as transition time from 3 to 5 mmHg. Results SpiraLith ® showed a higher CO 2 absorption capacity compared to AMSORB® Plus in GE Avance anesthesia machine (280.8 ± 116.9 L vs. 435.3 ± 101.6 L; mean difference 154.6 L; 95% CI, 72.5 to 236.6; p = 0.006). In Dräger Primus machines, CLIC Drägersorb ® Absorber 800 + demonstrated the highest CO 2 absorption capacity, outperforming both Drägersorb ® Free and SpiraLith ® , with considerable variability (582.5 ± 249.7 vs. 434.1 ± 138.4 vs.379.8 ± 70.4; p = 0.001). However, SpiraLith ® showed a significantly extended usage time and capacity until PiCO 2 increased from 3 to 5 mmHg when compared to the other two products. Conclusions In vivo performance of prefilled CO₂ absorbents may differ from previously reported in vitro results and can vary according to particle composition and device-specific conditions.