BACKGROUND: Parameters determining @entity1223 (CO) concentrations produced by anesthetic breakdown have not been adequately studied in clinical situations. The authors hypothesized that these data will identify modifiable risk factors. METHODS: @entity1223 concentrations were measured when partially desiccated @entity70342 lime was reacted with @entity5161 (1.5%) and @entity10233 (7.5%) in a Draeger Narkomed 2 anesthesia machine with a latex breathing bag substituting for a @entity1 . Additional experiments determined the effects of @entity544 (0 or 350 ml/min), fresh gas flow rates (1 or 4 l/min), minute ventilation (6 or 18 l/min), or absorbent quantity (1 or 2 canisters). End-tidal anesthetic concentrations were adjusted according to a monochromatic infrared monitor. RESULTS: @entity10233 produced approximately 20 times more CO than @entity5161 when completely dried absorbents were used. Peak CO concentrations approached 100,000 ppm with desflurane. Traces of water remaining after a 66-h drying time (one weekend) markedly reduced the generation of CO compared with 2 weeks of drying. Reducing the quantity of desiccated absorbent by 50% reduced the total CO production by 40% in the first hour. Increasing the fresh gas flow rate from 1 to 4 l/min increased CO production by 67% in the first hour but simultaneously decreased average inspiratory concentrations by 53%. @entity544 decreased CO production by 12% in completely desiccated absorbents. CONCLUSION: Anesthetic identity, fresh gas flow rates, absorbent quantity, and water content are the most important factors determining @entity1 exposures. Minute ventilation and @entity544 production by the @entity1 are relatively unimportant.

Physical factors affecting the production of XXXX from anesthetic breakdown.

@entity1 :: ('9606', 'Species') :: ['patient'] @entity1223 :: ('MESH:D002248', 'Chemical') :: ['carbon monoxide', 'Carbon monoxide'] @entity10233 :: ('MESH:C053562', 'Chemical') :: ['desflurane', 'Desflurane'] @entity70342 :: ('MESH:C012766', 'Chemical') :: ['barium hydroxide'] @entity544 :: ('MESH:D002245', 'Chemical') :: ['carbon dioxide', 'Carbon dioxide'] @entity5161 :: ('MESH:D007530', 'Chemical') :: ['isoflurane']
@entity1223 :: (MESH:D002248,Chemical) :: ['carbon monoxide']
