ABSTRACT
It has long been appreciated that anesthetic drugs alter chest wall function . For example, in 1858 John Snow observed that during chloroform anesthesia breathing was "sometimes performed only by the diaphragm whilst the intercostal muscles are paralyzed." Indeed, observations of the pattern of breathing were employed for many years as a clinically useful guide to the proper administration of anesthesia. More recently, anesthetic effects on chest wall function have attracted attention as a possible explanation for the impairment of pulmonary gas exchange observed during anesthesia. Also, anesthetic-induced changes in respiratory muscle activity may be useful to deduce the function of these muscles.
