Nonrebreathing valve for respiratory measurements in unsedated small mammals.

A nonrebreathing valve for measuring the respiratory volumes and gas exchange of unsedated, trained small mammals is described. The valve was easily fabricated from Plexiglas and latex flaps cut from a surgical glove. It has a low dead space and airflow restance and can be scaled to fit a variety of small mammal species. Ten hamsters were trained to breathe through the valve while expirate was collected. Respiratory frequency, tidal volume, minute volume, O2 uptake, CO2 output, respiratory exchange ratio, and ventilatory equivalent were measured.