I was discussing low flow with one of my old professors last week and we had a differing opinion on things. Curious what peoples take is. If I was running 0.2L of Air and 0.26L of O2. I would be delivering around 300ml/min. Adequate to meet the metabolic demands of the patient. Now her comment was that the patient expiring would dilute the gas in the circle system to a "hypoxic mixture". The Fio2 at those flows is aprox 60%, it would drop over time but if you are meeting the demands of oxygen consumption this would happen over a longer period right? I ran those flows for 2 hours with no problem.