How does a Venturi mask achieve different concentrations of oxygen?

The Venturi mask is designed to provide precise oxygen concentrations to patients by utilizing the principle of entrainment. This is achieved by mixing a specific flow of oxygen with the ambient air that a patient inhales. The mask contains interchangeable tips or adapters, each calibrated to allow a certain amount of oxygen to mix with the inspiratory air, creating varied oxygen concentrations.

When the oxygen flows through the mask at a high velocity, it creates a negative pressure that draws in ambient air through the openings in the mask. Depending on which tip is used, the ratio of oxygen to air can be adjusted, thus allowing healthcare providers to deliver precise oxygen levels tailored to the patient’s needs. This characteristic makes the Venturi mask particularly useful for patients with chronic respiratory conditions, ensuring that they receive the required oxygen without the risk of hyperoxia.

The other options do not accurately describe the mechanism of the Venturi mask. Adjusting the mask size or using different colored masks does not fundamentally alter the oxygen concentration delivered, and merely adjusting the pressure regulator also does not directly provide the varied concentrations of oxygen that the mask is specifically designed to offer.