The carbon dioxide absorption capacity of Amsorb is half that of soda lime.

UNLABELLED: A new CO(2) absorbent, Amsorb (A), which does not contain monovalent bases, is ideal because it does not degrade volatile anesthetics to either Compound A (from sevoflurane) or carbon monoxide (from desflurane, enflurane, or isoflurane). The CO(2) absorption capacity of A, however, has not been investigated under clinical conditions. In this study, we compared the longevity (time to exhaustion) and CO(2) absorption capacity (the volume of CO(2) absorbed before CO(2) rebreathing occurs) of A under low-flow anesthesia (1 L/min) with those of two soda lime absorbents-Medisorb (M) and Sodasorb (S)-by using a 750-mL ADU canister and a 1350-mL Aestiva 3000 canister. In the study with the ADU canister, the longevity of A was 213 +/- 71 min, significantly less than those of M (445 +/- 125; P < 0.01) and S (503 +/- 89; P < 0.001). The CO(2) absorption capacity (L/100 g absorbent) of A was 5.5 +/- 1.2, significantly less than those of M (10.7 +/- 1.7) and S (12.1 +/- 1.8; P < 0.001). In the study with the Aestiva 3000 canister, the longevity of A was 218 +/- 61 min, significantly less than those of M (538 +/- 136) and S (528 +/- 103; P < 0.001). The CO(2) absorption capacity (L/100 g absorbent) of A was 7.6 +/- 1.6, significantly less than those of M (14.4 +/- 1.8) and S (14.8 +/- 2.3; P < 0.001). These results indicate that the CO(2) absorption capacity of A is half that of M or S and that the difference in the CO(2) absorption capacity between A and M or S is almost constant, regardless of the canister design. IMPLICATIONS: The CO(2) absorption capacity of Amsorb is half that of Medisorb and Sodasorb under clinical low-flow (1 L/min) anesthesia with either a 750-mL Ohmeda ADU compact or a 1350-mL Ohmeda Aestiva 3000 canister.