A simple improvement in the EMO vaporizer.

The EMO (Epstein, Macintosh, Oxford) ether vaporizer has received worldwide acceptance as a simple thermo-compensated anaesthetic apparatus. Equipped with a Penlon bellows and a nonrebreathing valve, safe ether-air or methoxyflurane-air anaesthesia can be administered with this machine in almost any geographical location. An extensive bibliography of clinical papers related to the use of this apparatus is not indicated in this communication. Mention of references to its use, or anticipated use, in disaster areas or war theatres (Khandekar and Rama Rao, 1965; MacKay, 1965; O'Connor, 1961) is indicated, as such use demands a machine that is resistant to rust .and dust, corrosion, or inactivation of moving parts. Although the EMO may have a reputation for reliability in Great Britain, the rotor tends to "freeze" in some of the units when used in the United States (Ham, J., 1967, personal communication; Rendell-Baker, L., 1965, personal communication; Stetson, J. B., 1963, personal experience), Viet Nam (Brown, A., 1966, personal communication), and other countries (Stetson et al., 1966). The author has modified the rotor in an attempt to eliminate the possibility of binding or "freezing".