What is the percentage of oxygen delivered by a bag-valve mask (BVM)?

A bag-valve mask (BVM) is an essential tool used in emergency medical scenarios to provide positive pressure ventilation to patients who are apneic or have inadequate breathing. When delivering oxygen via a BVM, it is typically able to deliver approximately 100% oxygen to the patient, assuming the unit is correctly fitted and properly used.

The effectiveness of the BVM in delivering such a high concentration of oxygen largely depends on achieving an adequate seal around the patient's mask, which prevents room air from mixing in with the oxygen. In a controlled setting and when administered correctly, the use of supplemental oxygen from a cylinder connected to the BVM allows nearly pure oxygen to be delivered directly to the patient’s lungs, providing maximum oxygenation.

This high concentration is particularly crucial in emergency situations where time is critical, and optimal oxygen delivery can significantly improve patient outcomes, especially in cases of respiratory failure or cardiac arrest.