Fig. 1
From: Contemporary portable oxygen concentrators and diverse breathing behaviours -- a bench comparison
Respiratory flow and oxygen flow for a single breath during pulsed dose oxygen delivery. Oxygen is potentially ‘useful’ to the patient if delivered within the ‘alveolar’ tidal volume. Wastage of oxygen may occur if the oxygen pulse flow exceeds inspiratory flow, depending on the prevailing conditions. Note that the timing datum is the start of inspiratory flow