In Reply:—

We thank Dr. Sosis for his comment in which he wonders why we propose the combination of strong base free Amsorb with strong base containing CO2absorbents and not the simpler alternative of Amsorb alone.

As Dr. Sosis points out, Amsorb (Armstrong, Coleraine, Northern Ireland) has the advantage of not producing CO when used with volatile inhaled anesthetics. That makes it a most attractive CO2absorbent. However, we see a second issue here, and that is that Amsorb has been shown to have only half the CO2absorbing capacity of strong base containing absorbents. 1We actually confirmed that finding in one 2of the papers cited by Dr. Sosis in reference to Amsorb's advantage as a CO2absorbent. In clinical anesthesia, this characteristic of Amsorb results in higher consumption and consequently in higher costs. 3For these reasons, many anesthesiologists may hesitate to use Amsorb. We see our proposed combination, which takes advantage of an unexpected property of Amsorb, allowing both avoidance of CO production and optimum CO2absorption, as widening the range of choices available to anesthesiologists at the present time.

Higuchi H, Adachi Y, Arimura S, Kanno M, Satoh T: The carbon dioxide absorption capacity of Amsorb is half that of soda lime. Anesth Analg 2001; 93: 221–5
Knolle E, Heinze G, Gilly H: Small carbon monoxide formation in absorbents does not correlate with small carbon dioxide absorption. Anesth Analg 2002; 95: 650–5
Baum J, Van Aken H: Calcium hydroxide lime—A new carbon dioxide absorbent: A rationale for judicious use of different absorbents. Eur J Anaesthesiol 2000; 17: 597–600