The present invention relates to a device for measuring respiratory parameters of a patient. In one embodiment, the device 100 comprises a flow tube 101 and a body 102. The flow tube 101 is a hollow tube comprising: a first end 103, a second end 104 and at least one tube portion 105 (represented by dotted lines) wherein the tube portion is having a geometric construction capable of altering the rate/direction of air flow passing through the flow tube, thereby introducing a differential pressure between the first end 103 and the second end 104.
