Final answer:
A non-rebreathing mask can reach an O₂ concentration of 95% usually at an O₂ flow rate of 10 to 15 L/min, which must be adequately adjusted based on patient demand to prevent CO₂ buildup and ensure effective gas exchange.
Step-by-step explanation:
A non-rebreathing mask is a device used in medicine to deliver high concentrations of oxygen to patients who require it. The rate of oxygen flow must be set to match the patient's inspiratory demand to prevent re-inhalation of exhaled gases and maintain the desired oxygen concentration. A non-rebreathing mask can typically achieve an O₂ concentration of 95% with an oxygen flow rate that is sufficient to keep the reservoir bag at least partially inflated during inspiration, generally between 10 to 15 liters per minute.
The work of breathing increases when there is an increase in oxygen demand, requiring adjustments to either respiratory rate or tidal volume to maintain adequate alveolar ventilation and prevent carbon dioxide buildup. During this process, inspired air in the lungs, which has a higher partial pressure of oxygen (Po₂ = 150 mm Hg), will flow into the bloodstream where the partial pressure of oxygen (P₂o₂ = 100 mm Hg) is lower, in accordance with basic physics principles.
Therefore, while the precise flow rate necessary to achieve a 95% oxygen concentration with a non-rebreathing mask might vary slightly depending on factors such as fit and patient breathing pattern, the standard range of 10 to 15 L/min is commonly accepted in clinical practice.