Date of manufacture:
The EMO Inhaler was developed in the Nuffield Department of Anaesthetics, Oxford. It was introduced in 1956 as a means of providing accurate concentrations of Ether for use with the Oxford Inflating Bellows. The letters 'EMO' stand for Epstein, Macintosh, Oxford.
This particular vaporiser was originally calibrated for chloroform but has been modified by the substitution of a halothane calibration scale 0 - 4%. It is a temperature-compensated draw-over vaporiser. When an Oxford Inflating bellows is interposed between it and the patient, it can be used to administer anaesthesia in locations where conventional supplies of anaethetic gases are not available e.g. in a military environment. It imposes a low breathing resistance and is calibrated for intermittent flows as might be encountered during spontaneous or controlled ventilation and not for low continuous flows as would be the case for a plenum vaporiser. It should not be inserted into a part of the breathing system where it would be exposed to controlled ventilation pressures as this would result in calibration inaccuracies.
Epstein, H.G., Macintosh, R., Anaesthesia, 1956, 11, 83.