The effect of the administration of oxygen by different techniques and at varying flow rates through nasal cannulae was evaluated in patients with moderate and severe respiratory insufficiency. The amount of oxygen enrichment necessary to raise the arterial oxygen pressure to normal levels was variable, but a flow rate of 3 liters/min resulted in normal arterial oxygenation even in patients with moderately severe hypoxia. When oxygen was administered through nasal cannulae at flow rates less than 5 liters/min, there was no rise in arterial carbon dioxide pressure in 17 patients with alveolar hypoventilation and hypercapnia.
Cherniack RM, Hakimpour K. The Rational Use of Oxygen in Respiratory Insufficiency. JAMA. 1967;199(3):178-182. doi:10.1001/jama.1967.03120030082015