A patient with congestive heart failure is receiving 35% O2 through an air-entrainment mask at 6 L/min. What is the total output gas flow?

To determine the total output gas flow when using an air-entrainment mask, you need to consider both the flow of oxygen and the ambient air that is entrained. An air-entrainment mask works by mixing a set amount of oxygen with a certain proportion of room air to achieve a specific concentration of oxygen.

In this scenario, the mask is delivering 35% oxygen at a flow rate of 6 L/min from the oxygen source. The design of such masks typically allows for a specific ratio of air to oxygen. At a 35% oxygen concentration, the common ratio is approximately 1:1. This means for every liter of oxygen, about equal parts of room air is mixed in.

To calculate the total output gas flow, we need to factor in both the oxygen flow and the air flow. For every 1 liter of oxygen at a given setting, there will be about 1 liter of air entrained:

1. The oxygen input is 6 L/min.

2. Using a 1:1 air-oxygen ratio, we can estimate that it entrains approximately an equal amount of air, thus also 6 L/min of air.

Adding the two flows together (6 L/min of oxygen plus 6 L/min