Final answer:
A Venturi mask delivers a precise amount of oxygen, typically between 24% and 50% FiO2, controlled by changing the venturi nozzles which mix room air and oxygen at flow rates from 4 to 10 liters per minute.
Step-by-step explanation:
A Venturi mask is a medical device used to deliver a precise amount of oxygen to patients with respiratory conditions. It provides oxygen at specific flow rates to ensure a constant and accurate percentage of inspired oxygen (FiO2). This mask can deliver FiO2 levels typically between 24% and 50%, with flow rates usually set between 4 and 10 liters per minute. It achieves this by using a mixture of room air and oxygen, supplied through a venturi barrel which has color-coded nozzles to deliver the desired oxygen concentration.