Which of the following is NOT an example of a high flow system?

A simple mask is not considered a high flow system because it delivers a less precise concentration of oxygen compared to high flow systems. High flow systems are designed to provide a specific and controlled oxygen concentration to the patient, enabling better management of hypoxia.

In contrast, systems like the Venturi mask and air-entrainment nebulizer utilize mechanisms that precisely mix ambient air with a predetermined amount of oxygen, allowing for accurate delivery of oxygen concentrations. The high-flow cannula is also engineered to deliver a higher flow rate of oxygen, which ensures that the patient's needs for supplemental oxygen are effectively met.

Since the simple mask can deliver variable concentrations of oxygen based on the patient’s breathing pattern and does not maintain a high enough flow to significantly entrain room air, it cannot be classified as a high flow system. This makes it distinct from the other options, which are all capable of delivering a specific, high flow rate of oxygen with more consistent therapeutic outcomes.