Abstract: A device for measuring lung function parameters using quiet exhalation has a flow tube with a mouthpiece end and an outlet, a shutter covering the outlet of the flow tube, a controllable latch closing and releasing the shutter, a flow sensor for measuring flow in the flow tube following release of the shutter, a pressure sensor for measuring pressure in the flow tube prior to the release of the shutter, a latch controller connected to the pressure sensor and the controllable latch, and a check valve arranged in the flow tube or the shutter for allowing inhalation while the shutter is closed so that the device can be used throughout at least one inhalation and exhalation cycle.

Abstract: A flowmeter has a disposable flow tube and a part of the shutter which are in direct contact with exhaled air and protect the rest of the device from potential contamination with harmful viruses.