Target drive ventilation gain controller and method

Abstract

A gain controller and method for controlling the value of a gain is used in conjunction with an electrode array for detecting a signal representative of respiratory drive output of a patient during inspiration, and a lung ventilator for assisting inspiration of the patient. The gain controller comprises an input for receiving the signal representative of respiratory drive output; a comparator for determining whether the signal representative of respiratory drive output is higher or lower than a target drive signal; and a gain adjustment unit for increasing the value of a gain when the amplitude of the signal representative of respiratory drive output is higher than the amplitude of the target drive signal and for decreasing the value of this gain when the amplitude of the signal representative of respiratory drive output is lower than the amplitude of the target drive signal. The gain is applied to the signal representative of respiratory drive output to produce an amplified respiratory drive output representative signal used for controlling the lung ventilator. The advantage of target drive ventilation is that this mode of ventilation does not depend on pressure, flow or volume measurements. A leaky ventilatory line will introduce a change in respiratory drive which will change the ventilatory assist in order to return the respiratory drive to its target level. Also, changes in the patient's metabolic or patho-physiological status which result in altered respiratory drive will be compensated.

1 . A gain controller for adjusting, in relation to a target drive signal, the value of a gain applied to a signal representative of respiratory drive output of a patient during inspiration, to produce an amplified respiratory drive output representative signal for controlling a lung ventilator assisting inspiration of the patient, said gain controller comprising: 
 a first input for receiving the signal representative of respiratory drive output having a first amplitude;    a second input for receiving the target drive signal of a second amplitude;    a comparator for determining whether the amplitude of said signal representative of respiratory drive output is higher or lower than the amplitude of said target drive signal; and    a gain adjustment unit for increasing the value of said gain when the amplitude of said signal representative of respiratory drive output is higher than the amplitude of said target drive signal and for decreasing the value of said gain when the amplitude of the signal representative of respiratory drive output is lower than the amplitude of the target drive signal.    
     
     
         2 - 33 . (canceled)