A Nonresisting, Nonrebreathing Valve

Evaluation of a ventilator with fixed volume control and variable regulated pressure

“…Non-rebreathing system The small resistance, the negligible dead space and the elimination of rebreathing have the same advantages as have been described for children (39) The Fmk type of non-rebr~athing valve, m which the exhalation valve is occluded automatically during inhalation, makes the use of controlled respiratuon in the adult a much easier task (40). The operation of this valve is even more efficient when it is used with a positive and negative pressure ventilator Although thhe subatmospherlc pressure is not transmitted to the patient's airway, it serges to assure airtight closure of the inhalation valve diaphragm during expiration and prevents sticking of the tnsptratory and expiratory valve diaphragms.…”

Origins of paediatric anaesthesia in Canada

“…Stephen and his colleague, Dr Harry Slater, made significant changes and improvements regarding new anaesthetic agents and techniques (Stephen & Slater 1950) (Figure 5a, b). In particular, they developed a new non-rebreathing valve (Figure 3) whch soon gained widespread use (Stephen & Slater 1948). Its fascinating origin occurred in 1946 when Dr Stephen was at the Montreal Neurological Institute.…”

A New Valve for Controlled Respiration Anasthesia

“…More recently the use of curare with cyclopropane or other anaesthetic agents has made the technique of controlled res- (Macintosh and Mendelssohn, 1941). In America the Stephen-Slater (1948) nonrebreathing valve is widely used. They all, however, were designed primarily for use during spontaneous respiration anaesthesia.…”

“…This non-return expiratory valve may also be used as a non-rebreathing valve during spontaneous respiration anaesthesia (Stephen and Slater, 1948). And by removing the non-return valve, which easily slides out, the unit may be used as an ordinary expiratory valve.…”