## **Core Concept**
The question tests understanding of oxygen therapy delivery systems, specifically Venturi masks, which are used to provide a fixed concentration of oxygen to patients. The Venturi mask works on the principle of jet mixing, where oxygen flow entrains room air to deliver a specific oxygen concentration.

## **Why the Correct Answer is Right**
The Venturi mask is designed to deliver a precise fraction of inspired oxygen (FiO2) by using different color-coded jets that correspond to specific oxygen concentrations. The maximum oxygen concentration that can be delivered using a Venturi mask is 60%, which is achieved by using the appropriate jet. This is because as the oxygen flow rate increases, the entrainment of room air also increases, which dilutes the oxygen concentration. Therefore, the highest concentration that can be reliably delivered is 60%.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 24% - This is a lower concentration that can be delivered by a Venturi mask but is not the maximum.
- **Option B:** 40% - While some Venturi masks can deliver this concentration, it is not the maximum.
- **Option D:** 80% - This is too high for a Venturi mask, as they are not capable of delivering such high concentrations of oxygen.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Venturi masks are particularly useful for patients with chronic obstructive pulmonary disease (COPD) who may have a hypoxic drive to breathe. The fixed concentration of oxygen helps prevent suppression of this drive. The different concentrations are color-coded and correspond to specific clinical situations.

## **Correct Answer:** . 60%