| Patient-ventilator dyssynchrony is a problem that can't solve properly because the flow and pressure signals used to trigger and control the ventilator are interfered by the patient's respiratory muscle functional state and the airway resistance. So it's necessary to find a media to communicate the patient with the ventilator in order to improve the patient-ventilator synchrony and enhance the clinical curative effect.The diaphragm muscle is the most critical inspiratory muscle. The diaphragmatic electromyogram (EMG) changes earlier than the airway pressure or the flow. Its magnitude is in direct proportion to the inspiratory muscle activity, meanwhile its disappear time is the point that the patient's expiry begins. The characteristic of the diaphragmatic EMG signal is described in the paper. A diaphragmatic EMG acquisition system is established. A series of correlative researches are done on the diaphragmatic EMG signal processing and analysis to provide prophase results of the diaphragmatic EMG triggered and controlled ventilator theory.First, an acquisition system is established, which includes the components: the esophageal electrodes, the spirometer, the amplifier and the data acquired instrument, to record the diaphragmatic EMG, the flow and the assistant signals.Second, 3 methods, the match filter, the adaptive filter and the mathematical morphology filter, filter the acquired diaphragmatic EMG mixed with the ECG, respectively. The paper compares these 3 methods' arithmetic and their processed results.The third, the respiratory parameters, the inspiratory onset, the expiratory onset and the respiratory instantaneous cycle, which are contained in the clear diaphragmatic EMG, are analyzed and picked up by the methods combining the threshold detection and the improved mathematical morphology filter... |
