ATC provides an increase in respiratory comfort compared with IPS. The predominant cause for respiratory discomfort in the IPS mode seems to be lung over-inflation.
The interrupter technique is used to determine airway and tissue resistance. Their accuracy is influenced by the technical properties of the interrupter device and the compliance of the respiratory system. We investigated the influence of valve characteristics and respiratory system compliance on the accuracy of determining airway and tissue resistance by means of a computer simulation. With decreasing compliance we found increasing errors in both airway and tissue resistance determination of up to 34 and 71%, respectively. On this basis we developed a new occlusion valve, with special emphasis on rapid closing time and tightness in the closed state to improve the accuracy of resistance determination. The newly developed occlusion device greatly improves the accuracy of airway and tissue resistance determination. We conclude that respiratory system compliance is a limiting factor for the accuracy of the interrupter technique. To apply the interrupter technique in patients with extremely low respiratory system compliances, we need sophisticated technical devices.
Syntheses of substituted, especially of fluoro substituted benzoxathiole 1,1-dioxides, are described. These derivatives were transformed via the Peterson olefination into substituted 2-alkylidene derivatives 27. Diels-Alder reactions of 27 with 1,1-dimethoxy- and 1-methoxy-3-trimethylsiloxy-1,3-butadiene (30, 32) gave sulfone analogues 31 of griseofulvin (named sulfogriseofulvins). From Z-27, a number of cis-isomers with the relative stereochemistry of griseofulvin (cis-31) was prepared, and from E-isomers of 27, compounds (trans-31) with relative stereochemistry of epigriseofulvin were obtained. Some related compounds (33, 38) are synthesized by slight modifications. The stereochemistry is established by spectroscopic methods and crystal structure analyses. The compounds 31 were tested against three species of dermatophytes. The biological activities were all significantly lower than that of griseofulvin.
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