During a sleep study, which of the following is used to record breathing patterns?

The correct choice for recording breathing patterns during a sleep study is the thermocouple. A thermocouple measures temperature changes, and when placed appropriately, it can detect airflow by capturing the temperature of exhaled air. This allows for the assessment of breathing patterns, including both the rate and depth of respiration. It is particularly useful in sleep studies when monitoring snoring and breathing irregularities.

While other devices mentioned can also play roles in assessing various aspects of respiratory function, they do not specifically focus on recording breathing patterns in the same direct manner as a thermocouple. For instance, a pulse oximeter measures oxygen saturation in the blood, an electrocardiogram monitors heart activity, and a capnometer measures the concentration of carbon dioxide in exhaled air. While these measurements can provide valuable information about respiratory function, they do not directly record the pattern of breathing. Hence, the thermocouple is the most relevant tool in this context for capturing changes indicative of breathing during sleep studies.