Douglas bag

A Douglas bag is a device used in respiratory research to collect a person's exhaled breath for analysis. It consists of a large, airtight bag connected to a tube that captures breath directly from a person during breathing. By collecting a sample of exhaled gases, scientists can analyze oxygen, carbon dioxide, and other components to study lung function and metabolic processes. The bag’s design ensures precise collection without contamination or loss of gases, making it a valuable tool for respiratory assessment in both clinical and research settings.