NRBM

 An  Non-Rebreathing Oxygen Mask is a high-concentration oxygen delivery device designed for emergency use in critically hypoxic patients. It features a face mask with an attached reservoir bag and a system of one-way valves to prevent the rebreathing of exhaled carbon dioxide, allowing for the delivery of up to 95% FiO2. Its safe operation depends on a minimum oxygen flow of 10-15 L/min to keep the reservoir bag inflated. It is contraindicated where uncontrolled high-flow oxygen may be harmful (e.g., in some COPD patients) and carries a severe fire risk. It is a vital, immediate-intervention tool found in all emergency response settings.