Which function of a ventilator involves setting the amount of air delivered per breath?

The function of the ventilator that involves setting the amount of air delivered per breath is tidal volume. Tidal volume refers to the volume of air that is inhaled or exhaled during a single breath in normal breathing. In a mechanical ventilator context, it is crucial for ensuring that the patient receives adequate ventilation and oxygenation based on their specific medical needs.

Setting the correct tidal volume is essential to properly ventilate patients, as it helps to prevent complications such as hypoxia or hypercapnia. For patients with varying respiratory conditions, the tidal volume may need to be adjusted based on their lung capacity, compliance, and other factors to optimize their breathing support.

In contrast, respiratory rate refers to how many breaths are delivered in a minute, inspiratory-to-expiratory ratio indicates the length of time spent inhaling versus exhaling, and pressure relief is a safety feature that prevents excessive pressure in the ventilatory circuit. While these factors are all important in the overall function of a ventilator, they do not directly relate to the specific volume of air delivered per breath, which is why tidal volume is the correct answer.