Method and apparatus for assisting expulsional movement of pulmonary secretions via supramaximal flows

摘要

There is described a non-invasive device designed to assist expectoration of pulmonary secretions in humans, particularly in those whose natural exhalation and natural coughing ability are impaired. The device has a valve that opens fully in not more than 10 milliseconds, a pressure sensing means generating a signal indicative of a pressure in the upper part of the subject's respiratory tract, detecting means indicating the imminent collapse of the subject's respiratory tract or a part thereof, and control means opening or closing the valve respectively in response to the signals from the sensing means and the detecting means so as to create supramaximal flows in the respiratory tract in order to stimulate the movement of secretions towards the mouth of the subject. The valve opening/closing sequence is totally subject-controlled in accordance with a method of the invention which comprises the step of inducing supramaximal flows by determining a pressure threshold for the subject to be able to effect multiple openings and closings of the valve during a single respiratory cycle, determining a subject-specified parameter indicative of a substantial collapse of the subject's respiratory tract, and having the subject exhale against the valve to effect a rapid sequence of valve opening/closing cycles which cause the supramaximal flows and resulting movement of secretions towards the mouth of the subject.