Inspiratory proportional pressure assist ventilation controlled by a

Abstract

To control a lung ventilator comprising an inspiratory implement to be worn by the patient, an air supply system for supplying air to the inspiratory implement, and a control unit for controlling the air supply system, electromyographic signals produced by the patient's diaphragm are detected by an array of electrodes passing through the center of the patient's diaphragm depolarizing region. The position of the center of the patient's diaphragm depolarizing region is determined through detection of a reversal of polarity of the electromyographic component of the electrode-detected electromyographic signals. First and second electromyographic signals detected by the electrodes of the array on opposite sides of the patient's diaphragm depolarizing region are subtracted from each other, this subtraction cancelling the noise components of the first and second electromyographic signals but adding the respective electromyographic components of these first and second signals together to produce an electromyographic signal having an improved signal-to-noise ratio, having a reduced electrode-position-induced filter effect, and being representative of a demand to inspire from the patient's brain. The electromyographic signal of improved signal-to-noise ratio is finally supplied as input signal to the control unit of the lung ventilator for controlling the air supply system and therefore the inspiration assist in relation to the electromyographic signal of improved signal-to-noise ratio and of reduced electrode-position-induced filter effect, and therefore in relation to the demand to inspire from the patient's brain.