The absorption and degradation of isoflurane and I-653 by dry soda lime at various temperatures.

The capacity of dry soda lime to absorb and degrade isoflurane and a new inhaled anesthetic, I-653, was measured at normal, decreased, and increased temperatures. Both agents were absorbed at all temperatures tested (0, 20, 40, and 60 degrees C). Absorption of isoflurane into a molecular sieve-like portion of dry soda lime was 30% (40 degrees C) to 115% (0 degrees C) greater than that of I-653. Similarly, the quasipartition coefficient for dry soda lime was 18% (0 degrees C) to 212% (20 degrees C) greater with isoflurane than with I-653. Degradation rates for the two anesthetics were comparable, although slightly higher for I-653 than for isoflurane. Fractional degradation rates for both agents increased with increasing temperature and decreased as the concentration of agent increased.