The most effective drug delivery occurs when the patient achieves a flow within the Optimum Inspiratory Flow Range.
At flow rates outside this optimum range, certain devices may deliver an effective (rather than optimum) dose. However, inspiratory flow rates outside the optimum range may reduce pulmonary deposition significantly.
By measuring the inspiratory flow of a patient using an inhaler, a comparison with the flow rates associated with most desirable performance and clinical effect can be made. This can help to identify those who are using their inhaler sub-optimally.