What FiO2 range can a partial nonrebreather mask provide?

A partial nonrebreather mask is designed to deliver a higher concentration of oxygen compared to other masks such as simple face masks. It can provide an FiO2 (fraction of inspired oxygen) range typically between 40% to 70%. This is achieved because the mask has a reservoir bag that allows for the collection of oxygen from the delivery system, which is then available for the patient to inhale.

The bag partially fills with oxygen, allowing the patient to receive a mix of oxygen from the reservoir and room air on exhalation. This mechanism enables a significant FiO2 concentration to be delivered. However, the precise FiO2 can vary based on factors such as the patient’s respiratory effort, mask fit, and flow rate of oxygen being administered.

The correct answer reflects this ability of the partial nonrebreather mask to provide a more concentrated oxygen supply compared to lower FiO2 delivery systems while remaining below the more concentrated levels delivered by a full nonrebreather mask or mechanical ventilation equipment, which can achieve higher percentages.