APPARATUS AND METHOD FOR CONTROLLING GAS-DELIVERY MECHANISM FOR USE IN RESPIRATORY VENTILATORS

摘要

A method of controlling a mechanical ventilator is provided which is capable of increasing a stability margin in the controlling of a gas-deliver y mechanism for the mechanical ventilator. The flow rate F of an assisting gas is measured, and an observer 54 estimates a flow rate ~ of the assisting gas, A difference .DELTA.F between the measured flow rate F and estimated flow rate ~ is then determined, and information on a patent's respiratory effort pressure P mus is obtained A target pressure P in for controlling a gas-delivery mechanism 20 is calculated on t he basis of this information. When the target pressure P in is calculated on the basis o f the flow-rate difference .DELTA.F, an allowance with respect to the stability limit of the overall system 14 can be increased. This enables the runaway to rarely occur even when an actual overall system is varied. Moreover, the responsibility of assist respiration can be improved as compared with that of the related at PAV method.