RESPIRATION 1 53 



days during which there was danger from anoxaemia. Patients 

 can sleep comfortably during the administration. 



The apparatus was afterwards simplified, with the special object 

 of making it both easy for a nurse to handle, and available for 

 front line and stretcher work, including treatment of "shock" 

 cases. Figure 50 shows the arrangement of the apparatus. It con- 

 sists of : ( I ) an oxygen cylinder provided with an easily worked 



TAP to 



^^/■^^ OPENING 

 f ^/TOAJR 



MAIN 

 VALVe 



Figure 50. 

 Api)aratus for administering oxygen. 



and efficient main valve ; (2) a pressure gauge showing how much 

 oxygen is in the cylinder; (3) a reducing valve which reduces 

 the pressure to a small amount which remains constant till the 

 cylinder is exhausted; (4) a graduated tap indicating the flow of 

 oxygen in liters per minute; (5) thick- walled rubber tubing con- 

 veying the oxygen to the patient and a light rubber bag; (6) a 

 face piece with a minimum of dead space, and provided with 

 elastic straps and a pneumatic cushion which can be taken off for 

 disinfection. 



The patient can inspire and expire freely through an opening 

 in which there is a rubber flap to cause a very slight resistance. 

 During expiration the oxygen collects in the bag, and is sucked 

 into the face piece at the beginning of inspiration. From the move- 

 ments of the bag it can be seen at any time whether the patient 

 is receiving the oxygen. To put the apparatus in action the main 

 valve is opened freely, and the tap is adjusted to give 2 liters a 

 minute or whatever greater or less amount suffices. With a de- 

 livery of 2 liters a minute a 40-foot cylinder would last nearly 

 ten hours. 



