Patent ID: 8434479

Claim:
A method comprising: one or more flow sensor processing modules of a medical ventilator receiving an output signal of an exhalation flow sensor including a hot-wire anemometer, the output signal indicative of a rate of flow of expired gas by a patient; the one or more flow sensor processing modules compensating for transient thermal response of the hot-wire anemometer resulting from a change in concentration of gas types included within the expired gas by applying a corrective modification to the output signal or a value based thereon that is based at least in part on a fraction of inspired oxygen (FiO2) being supplied to the patient by the medical ventilator; wherein the one or more flow sensor processing modules are implemented in one or more microprocessors and one or more computer-readable media, the one or more computer-readable media having instructions tangibly embodied therein that are executable by the one or more microprocessors; wherein the corrective modification involves a constant and an exponentially decaying factor; and wherein the corrective modification comprises multiplying the output signal or the value based thereon by a mix transition multiplier generally represented as: M= 1.0 +K *ΔO2Conc* e −t/T where, K=0.00125 T=15 seconds t=time elapsed since FiO2 setting change ΔO2Conc=Current FiO2 setting−Previous FiO2 setting.