| pubmed-article:7640121 | pubmed:abstractText | We have compared concentrations of degradation products in the circle system during sevoflurane anaesthesia at different fresh gas flows. Twenty-four patients underwent sevoflurane anaesthesia with fresh gas flows of 1 litre min-1 (1L group), 3 litre min-1 (3L group), or 6 litre min-1 (6L group) (n = 8 in each group). During anaesthesia, the concentrations of degradation products were measured every hour, and the temperature of soda lime, end-tidal carbon dioxide concentrations, inspired and end-tidal sevoflurane concentrations, and carbon dioxide elimination were measured. CF2 = C (CF3)-O-CH2F (compound A) was the only degradation product detected. The mean maximum concentration of compound A was 19.7 (SD 4.3) ppm in the 1L group, 8.1 (2.7) ppm in the 3L group and 2.1 (1.0) ppm in the 6L group (P < 0.05). The maximum temperature of soda lime was 44.6 (1.5) degrees C in the 1L group, 37.0 (4.4) degrees C in the 3L group and 29.1 (5.1) degrees C in the 6L group (P < 0.05). There were no significant differences in end-tidal sevoflurane concentration or mean carbon dioxide elimination between the groups. Only compound A was detected following anaesthesia, with higher concentrations observed at lower flow rates. | lld:pubmed |
