What is a warning related to portable oxygen use?

The correct answer highlights a critical safety aspect of using portable oxygen systems. Oxygen flow tables are designed to provide guidance regarding the expected flow rates and duration of oxygen supply based on specific conditions and equipment. However, the accuracy of these tables can be significantly affected by the type of mask being used, as different masks have varying flow characteristics and resistance.

For instance, a mask designed for a higher flow rate may deliver oxygen differently than one meant for lower flow situations. This inconsistency can lead to incorrect assumptions about how long the oxygen supply will last or how effectively it's being delivered to the patient. Therefore, it's vital for users to be aware that the tables should be treated as guidelines rather than definitive measures, especially when considering different types of masks in use.

Awareness of this warning is essential for ensuring that oxygen delivery remains effective and safe during critical situations, especially in medical emergencies or high-altitude scenarios.