Final answer:
The highest concentration of O2 for a patient with viral pneumonia and low pulse ox readings is provided by a nonrebreather mask, which can deliver about 90-100% oxygen.
Step-by-step explanation:
A patient with viral pneumonia experiencing pulse ox readings fluctuating between 79% and 88% indicates significant hypoxemia, a condition of low blood oxygen levels. The oxygen delivery system that provides the highest concentration of O2 among the options given is the nonrebreather mask. This mask includes a reservoir bag attached to an oxygen source, delivering approximately 90-100% oxygen, and has valves to prevent exhaled air from returning to the bag.
This makes the nonrebreather mask the most appropriate choice for this patient to correct their severely low oxygen saturation and meet their high oxygen demands. The other options - a Venturi mask, simple face mask, and partial rebreather mask - do not offer the high concentration of oxygen needed in this acute setting. A pulse oximeter is commonly used to monitor oxygen saturation in patients and guide treatment decisions, such as selecting the appropriate oxygen delivery system.