Contusion of the Myocardium

BRiTJUNLthe cycle, instead of runninlg to waste.If the flow is adjusted as described, the pressurle within the bladder during expiration should be less than within the face- piece, the valve of which will therefore be kept shut, and consequently no oxygen will pass into the mask.(4) During inspiration the bladder acts as a reservoir of supply.If there were no such reservoir the patient wotuld be depenldent solely on the oxygen flowing through the tubing at the time.Unless the flow was very extravagant he would quickly empty the tubing and feel suffocated.Points of Importance There are three important points in regard to oxygen cylinders which apply to all methods of administration, the-one described above included, but which are not yet universally known; they a-re therefore mentioned.First, effective giving of oxygen by any face apparatus necessi- tates oxygen flows of the order of 5 to 8 litres per minute, and consequently it is desirable to use large cylinders (that is, 100 cu.ft.).The ordinary small 20-cu.ft.cylin- ders, so frequently seen, contain only approximately 570 litres and consequently can last for little more than an hour.Secondly, in order to determine how much oxygen there is within a cylinder it is essential that a pressure gauge be attached, otherwise it is impossible to have any idea.Thirdly, oxygen cylinders should always be fitted with automatic pressure regulators, securing delivery at a constant low pressure (for example, 5 pounds); otherwise-as when an adjustment valve alone is fitted- the delivery pressure falls all the time as the cylinder empties, and must necessitate repeated opening up of the valve unless the flow is correspondingly to fall.Summary A simple method is described of converting the civilian respirator to an oxygen face-piece apparatus.