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An improved carbon dioxide absorber for use in a closed circuit patient breathing system has a canister insertable in the breathing circuit for receiving recirculating breathing gases. The canister contains a pelletized CO2 absorbent material that removes the CO2 from the breathing gases passing thr

An improved carbon dioxide absorber for use in a closed circuit patient breathing system has a canister insertable in the breathing circuit for receiving recirculating breathing gases. The canister contains a pelletized CO2 absorbent material that removes the CO2 from the breathing gases passing through the absorber. A quantity of the CO2 absorbent material is treated with a chemical indicator such that the chemical indicator makes a color change indicative of the state of the absorptive capacity of the absorbent material. A separate quantity of the CO2 absorbent material is treated with a second chemical indicator. The second chemical indicator changes color to indicate the degree of dryness of the CO2 absorbent material. The second chemical indicator may comprise cobalt chloride and serves to indicate the potential for excessive heat generation and toxic gas generation conditions within the CO2 absorbent canister.

대표청구항 ▼

What is claimed is: 1. An improved CO2 absorber for a patient breathing circuit capable of indicating the potential for, or existence of, hazardous conditions in the CO2 absorber, the breathing circuit recirculating CO2 laden breathing gases which may also contain an anesthetic agent, said absorber

What is claimed is: 1. An improved CO2 absorber for a patient breathing circuit capable of indicating the potential for, or existence of, hazardous conditions in the CO2 absorber, the breathing circuit recirculating CO2 laden breathing gases which may also contain an anesthetic agent, said absorber comprising: a canister suitable for insertion in the breathing circuit so that the recirculating breathing gases pass through the canister, the canister being formed to permit viewing of contents of the canister; a pelletized CO2 absorbent material in said canister for removing CO2 from breathing gases, said absorbent material being susceptible to drying by the breathing gases in the breathing circuit, at least a portion of the pellets of absorbent material having an indicator changing color from a first color to a second color as the absorptive capacity of the CO2 absorbent material becomes exhausted; and a plurality of sentinel pellets of CO2 absorbent material disposed throughout the pelletized CO2 absorbent material, said sentinel pellets containing a cobalt chloride substance and changing from a third color to the second color to indicate the dehydration of the CO2 absorbent material of the sentinel pellets; wherein the first color and the third color are different colors. 2. An improved CO2 absorber according to claim 1 wherein substantially more of said pelletized CO2 absorbent material is present in the CO2 absorber canister than sentinel pellets. 3. An improved CO2 absorber according to claim 2 wherein said sentinel pellets comprise 10% of the CO2 absorbent material in the said canister. 4. An improved CO2 absorber according to claim 1 wherein the change of color of the sentinel pellets from the third color to the second color indicates the generation of a toxic gas by the CO2 absorbent material. 5. An improved CO2 absorber according to claim 4 wherein said anesthetic agent comprises desflurane, enflurane, and isoflurane, and said toxic gas is carbon monoxide (CO). 6. An improved CO2 absorber according to claim 4 wherein said anesthetic agent is halothane and wherein said toxic gas is BCDFE (2-bromo-2-chloro-1,1-difluoroethylene). 7. An improved CO2 absorber according to claim 4 wherein said anesthetic agent is sevoflurane wherein said toxic gas is compound A (fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether). 8. An improved CO2 absorber according to claim 1 wherein said absorber is further defined as the change of color of the sentinel pellets from the third color to the second color indicates a hazardous condition comprising an elevated temperature within the absorber. 9. An improved CO2 absorber according to claim 8 wherein said elevated temperature is a temperature in excess of 110° Centigrade (230° Fahrenheit). 10. An improved CO2 absorber according to claim 1 wherein said CO2 absorbent material further comprises soda lime or baralyme. 11. An improved CO2 absorber of claim 1, wherein the cobalt chloride substance changes from the third color to the second color to indicate that the absorbent material has exceeded a threshold temperature. 12. A CO2 absorber for a patient breathing circuit that indicates the existence of a hazardous condition within the CO2 absorber, the patient breathing circuit recirculating CO2 laden breathing gases containing an anesthetic agent to the CO2 absorber, the CO2 absorber comprising: a canister suitable for insertion in the breathing circuit so that the recirculating breathing gases pass through the canister, the canister being formed to permit viewing of contents of the canister; a pelletized CO2 absorbent material in the canister that removes CO2 from the breathing gases, the CO2 absorbent material being susceptible to drying by the breathing gases in the breathing circuit, at least a portion of the pelletized CO2 absorbent material having an indicator that changes color as the absorptive capacity of the material becomes exhausted; and a plurality of sentinel pellets of CO2 absorbent material disposed throughout the pelletized CO2 absorbent material, the sentinel pellets containing a cobalt chloride substance that changes from a first color to a second color to indicate the hydration level of the sentinel pellets. 13. The CO2 absorber of claim 12, wherein the cobalt chloride substance changes from the first color to the second color to indicate that the absorbent material has exceeded a threshold temperature. 14. The CO2 absorber of claim 13, wherein the threshold temperature is 110° centigrade. 15. The CO2 absorber of claim 12 wherein the cobalt chloride substance changes from the first color to the second color to indicate that the sentinel pellets have become dehydrated.