in EMS that considered high flow, you can look it up in any EMS protocol. Wikipedia: High flow oxygen delivery In cases where the patient requires a flow of up to 100% oxygen, a number of devices...
I`m an EMT/LPN worked over 5 years in a 911 ambulance. Our protocol was to give high flow, at least 15LPM via NRBM for everybody with respiratory distress, regardless COPD. You give 4 LPM via NC, and...