Abstract: In a respiratory apparatus for treatment of sleep apnea and other disorders associated with an obstruction of a patient's airway and which uses an airflow signal, an obstruction index is generated which detects the flattening of the inspiratory portion of the airflow. The obstruction index is used to differentiate normal and obstructed breathing. The obstruction index is based upon different weighting factors applied to sections of the airflow signal thereby improving sensitivity to various types of respiration obstructions.

Abstract: Methods and apparatus for detecting the occurrence of a potential or actual overpressure during assisted ventilation are described. A blower (10) supplies pressurised gas to a conduit (12), and in turn to a patient mask (11) for connection with the entrance of a patient's airways. A pressure sensor (17, 18) detects the delivered pressure in the mask (11), which is provided to a controller (16). The controller (16) has operation over the blower (10) by way of a servo (19) and motor (20). The controller (16) determines a relatively longterm average of the pressure signal, and compares it against a threshold value (40). If the threshold value is approached or exceeded, the controller (16) controls the blower (10) and thus the supplied pressure to the patient. The effect of the control can be to limit or reduce the supplied gas pressure. The relatively longterm average can be of the order of minutes, or taken over ten or more breaths.

Abstract: An implantable cardiac device includes electrodes for sensing and pacing the heart, and optionally, defibrillation electrodes. The IECG sensed in the heart is processed to derive raw sense signals indicative of whether the sensed QRS complexes exceed a predetermined range. These signals are used to control the pacing pulses, and to detect high amplitude noise. This noise is differentiated from tachycardia.