Target device for regulating ventilation during voluntary hyperpnea

A ventilatory target device is described enabling subjects to maintain specified levels of ventilation during voluntary hyperpnea. Inspired air passes through a linear resistor. The associated pressure drop is measured and displayed by a mechanical manometer with a very slow response. This time-mean pressure is proportional to time-mean inspiratory flow and thus to inspired minute ventilation. Construction and calibration are described. Inspiratory resistances range between 0.6 and 1.9 cmH2O X 1(-1)S for devices with capacities up to 240 and 80 l/min, respectively. The device is simple, cheap, stable, portable, rugged, unpowered, and accurate. Inexperienced subjects quickly learn to use it and can maintain ventilations within about 5% of specified values.