When using oxygen, you must always know how to calculate the volume of oxygen available to assess the autonomy of the technique and thus plan the replacement of cylinders in time:
the total volume of O2 available = cylinder volume x pressure read on the manometer (bars)
volume actually available = total volume -10%
autonomy (min.) = volume actually available / flow rate administered to the patient (l/min.).
Example: 5 liter O2 cylinder, pressure of 100 bars, flow rate of 15 l/min.
autonomy = ((5 x 100) -10%) / 15 = 30 min.
Apart from minor trauma and superficial lesions, most patients need to be oxygenated. This is the case for all serious victims (multiple trauma, burns), patients with respiratory signs (rapid, panting or too low frequency of breathing), circulatory signs (rapid pulse or on the contrary too slow), nervous (behavioral disorders, consciousness) or skin (cyanosis, sweats) ... Oxygen is also necessary for chronic respiratory insufficiency whose ventilatory state has worsened.