Abstract: A method and apparatus for providing ventilatory assistance to a spontaneously breathing patient an error signal (56) is computed that is the difference between a function of respiratory airflow (54) over a period of time and a target value (52). Using a servo loop, air is delivered to the patient at a pressure that is a function of the error signal, the phase of the current breathing cycle, and a loop gain that varies depending on the magnitude of the error signal. The loop gain increases with the magnitude of the error signal, and the gain is greater for error signals below a ventilation target than for error signals above the ventilation target value. The target value (52) is an alveolar ventilation that takes into account the patient's physiologic dead space.

Abstract: A method of operating a CPAP apparatus in which the interface pressure is controlled to rapidly drop at the start of expiration by an expiratory relief pressure (ERP) that is independent of instantaneous respiratory flow, following which the pressure rises to an inspiratory level at or shortly before the end of expiration, or at the onset of an expiratory pause, if any. The ERP is an increasing function of the inspiratory pressure. The expiratory pressure follows a template that is a function of the expected expiration time, the magnitude of the template being equal to the ERP. The current estimated proportion of expiration is determined by comparing the expiration time of the breath in progress to low-pass filtered expiratory durations measured for a number of the preceding breaths.

Abstract: Methods, systems and/or apparatus for slowing a patient's breathing by using positive pressure therapy. In certain embodiments, a current interim breathing rate target is set, and periodically the magnitude of a variable pressure waveform that is scaled to the current interim breathing rate target is increased if the patient's breathing rate is greater than the interim breathing rate target in order to lengthen the patient's breath duration. The magnitude of the pressure increase may be a function of the difference between the interim breathing rate target and the patient's breathing rate. The interim breathing rate target may be periodically reduced in response to the patient's breathing rate slowing down toward the current interim breathing rate target. The variable pressure waveform cycles from an inhalation phase to an exhalation phase when the patient airflow decreases to a cycle threshold, the cycle threshold being a function of flow versus time within a breath and generally increasing with time.

Abstract: The present technology relates to methods and apparatus to provide ventilation to patients. In particular, the present technology relates to changing ventilator parameters to match changing patient metabolic demand.

Abstract: Methods, systems and/or apparatus for slowing a patient's breathing by using positive pressure therapy. In certain embodiments, a current interim breathing rate target is set, and periodically the magnitude of a variable pressure waveform that is scaled to the current interim breathing rate target is increased if the patient's breathing rate is greater than the interim breathing rate target in order to lengthen the patient's breath duration. The magnitude of the pressure increase may be a function of the difference between the interim breathing rate target and the patient's breathing rate. The interim breathing rate target may be periodically reduced in response to the patient's breathing rate slowing down toward the current interim breathing rate target. The variable pressure waveform cycles from an inhalation phase to an exhalation phase when the patient airflow decreases to a cycle threshold, the cycle threshold being a function of flow versus time within a breath and generally increasing with time.

Abstract: A ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation when the patient's respiratory flow passes a threshold level. The threshold generally increases from the beginning of inspiration to the end of inspiration. The increase can be linear over all or only a portion of the inspiratory cycle, and the threshold can be adjusted so that cycling is prevented during the initial portion of an inspiratory cycle. The minimum and maximum levels may both be functions of peak flow and the threshold may increase as a function of elapsed inspiratory time. The rate at which the threshold increases from a minimum level to a maximum level may be adjustable for individual patient needs and may be determined from previous breaths.

Abstract: A method and apparatus for determining suitable settings for a servo-ventilator to be used during a treatment period. Respiratory characteristics of a patient are measured during a learning period preceding the treatment period. With these measured characteristics, a target ventilation setting may be calculated by alternative methods. The calculated setting may then be used for enforcing a minimum ventilation during the treatment period where ventilatory support is provided with a servo-controlled ventilator.

Abstract: A ventilator device delivers ventilatory support to a patient in a back up timed mode when patient respiration is not detected or a spontaneous mode when patient respiration is detected. The timing threshold governing the back-up mode is chosen to deviate from normal expected respiration time for the patient to promote patient initiated ventilation in the spontaneous mode but permit back-up ventilation in the event of apnea. Automated adjustments to the timing threshold during the timed mode are made from the less vigilant timing threshold to a more vigilant threshold at or near a timing of normal expected breathing of the patient. Such adjustments may be made from a minimum to a maximum vigilance timing settings or incrementally there between as a function of time in the timed mode which is preferably the number of delivered machine breaths.

Abstract: A respiratory treatment apparatus and method in which a leak is determined by using an averaging window. The window starts at the present time and extends back in time to a point determined according to a current one of progressively detected phase measures of a first respiratory cycle and a corresponding phase measure attributable to a preceding second respiratory cycle. In another aspect, a jamming index indicates whether the leak is rapidly changing. To the extent that jamming is high, the leak estimate used progressively changes from that using sliding breath-window averaging to a more robust and faster responding low-pass filter method, and adjustment of ventilatory support based on measures employing estimated respiratory flow is slowed down or stopped.

Abstract: A ventilator device delivers ventilatory support to a patient in a back up timed mode when patient respiration is not detected or a spontaneous mode when patient respiration is detected. The timing threshold governing the back-up mode is chosen to deviate from normal expected respiration time for the patient to promote patient initiated ventilation in the spontaneous mode but permit back-up ventilation in the event of apnea. Automated adjustments to the timing threshold during the timed mode are made from the less vigilant timing threshold to a more vigilant threshold at or near a timing of normal expected breathing of the patient. Such adjustments may be made from a minimum to a maximum vigilance timing settings or incrementally there between as a function of time in the timed mode which is preferably the number of delivered machine breaths.

Abstract: A method and apparatus that provides an expert system for determining respiratory phase during ventilatory support of a subject. Discrete phase states are partitioned and prior probability functions and observed probability functions for each state are defined. The probability functions are based upon relative duration of each state as well as the flow characteristics of each state. These functions are combined to determine phase probabilities for each state using Bayes' theorem. The calculated probabilities for the states may then be compared to determine which state the subject is experiencing. A ventilator may then conform respiratory support in accordance with the most probable phase. To provide a learning feature, the probability functions may be adjusted during use to provide a more subject specific response that accounts for changing respiratory characteristics.

Abstract: A respiratory treatment apparatus and method in which a leak is determined by using an averaging window. The window starts at the present time and extends back in time to a point determined according to a current one of progressively detected phase measures of a first respiratory cycle and a corresponding phase measure attributable to a preceding second respiratory cycle. In another aspect, a jamming index indicates whether the leak is rapidly changing. To the extent that jamming is high, the leak estimate used progressively changes from that using sliding breath-window averaging to a more robust and faster responding low-pass filter method, and adjustment of ventilatory support based on measures employing estimated respiratory flow is slowed down or stopped.

Abstract: Methods and apparatus for assessing the condition of and treating patients for heart failure by the delivery of continuous positive airway pressure are disclosed. Treatment of obstruction due to reflex vocal cord closure often experienced by heart failure patients is distinguished from treatment of upper airway obstruction typically associated with Obstructive Sleep Disorder Treatment may also be implemented by delivering synchronized cardiac pressure oscillations superimposed on a respiratory pressure level to provide assistance for the heart. Heart treatment pressure dose indicator may be calculated for prescribing and monitoring the delivery of treatment. The apparatus may also generate data to track heart failure condition that may be indicative of the degree of severity of heart failure based upon breathing patterns to assist in the diagnosis and management of heart failure patients.

Abstract: In a CPAP or positive pressure ventilation system, leak is determined at each instant by a lookback for a time as long as single breath to establish the start of an averaging window over which low-pass filtered values used in the determination of a parameter of a leak model are averaged. A jamming index indicates whether the leak is rapidly changing. To the extent that jamming is high, the leak estimate used progressively changes from that using sliding breath-window averaging to a more robust and faster responding low-pass filter method, and adjustment of ventilatory support based on measures employing estimated respiratory flow is slowed down or stopped.

Abstract: A method and apparatus for treating sleep disordered breathing. An arousal index is determined for use in an outer loop of a control algorithm, the arousal index being a measure of the frequency of sleep arousals. The respiratory airflow signal in an inner loop of the control algorithm is monitored to detect an airway obstruction. If the arousal index is high, then the sensitivity of obstruction detection and/or the aggressiveness of the treatment is increased, and if the arousal index is low, then the sensitivity of the obstruction detection and/or the aggressiveness of the treatment is decreased.

Abstract: A respiratory treatment apparatus implements pressure delivery control settings by improved set-up procedures. In such an embodiment, a processor may automate setting of parameters for delivering a controlled flow of breathable gas. Data sets of pressure delivery parameter settings may be associated with one or more respiratory pathology indicators. The respiratory pathology indicators may each represent a different respiratory condition diagnosis. The processor may then prompt for an input of at least one of the respiratory pathology indicators. In response to the input, a particular set of pressure delivery parameter settings associated with the input respiratory pathology indicator may then serve as a basis for setting controls for delivering a controlled flow of breathable gas for respiratory treatment.

Abstract: A ventilator device delivers ventilatory support to a patient in a back up timed mode when patient respiration is not detected or a spontaneous mode when patient respiration is detected. The timing threshold governing the back-up mode is chosen to deviate from normal expected respiration time for the patient to promote patient initiated ventilation in the spontaneous mode but permit back-up ventilation in the event of apnea. Automated adjustments to the timing threshold during the timed mode are made from the less vigilant timing threshold to a more vigilant threshold at or near a timing of normal expected breathing of the patient. Such adjustments may be made from a minimum to a maximum vigilance timing settings or incrementally there between as a function of time in the timed mode which is preferably the number of delivered machine breaths.

Abstract: A ventilator device delivers ventilatory support to a patient in a back up timed mode when patient respiration is not detected or a spontaneous mode when patient respiration is detected. The timing threshold governing the back-up mode is chosen to deviate from normal expected respiration time for the patient to promote patient initiated ventilation in the spontaneous mode but permit back-up ventilation in the event of apnea. Automated adjustments to the timing threshold during the timed mode are made from the less vigilant timing threshold to a more vigilant threshold at or near a timing of normal expected breathing of the patient. Such adjustments may be made from a minimum to a maximum vigilance timing settings or incrementally there between as a function of time in the timed mode which is preferably the number of delivered machine breaths.

Abstract: A respiratory flow limitation detection device, which can include an airway pressure treatment generator, determines a flow limitation measure (506) based one or more shape indices for detecting partial obstruction and a measure of a patient's ventilation or respiratory duty cycle. The shape indices may be based on function(s) that ascertain the likelihood of the presence of M-shaped breathing patterns and/or chair-shaped breathing patterns. The measure of ventilation may be based on analysis of current and prior tidal volumes to detect a less than normal patient ventilation. The duty cycle measure may be a ratio of current and prior measures of inspiratory time to respiratory cycle time to detect an increase in the patient's inspiratory cycle time relative to the respiratory cycle time. A pressure setting based on the flow limitation may then be used to adjust the treatment pressure to ameliorate the patient's detected flow limitation condition.

Abstract: A method and apparatus for treating sleep disordered breathing. An arousal index is determined for use in an outer loop of a control algorithm, the arousal index being a measure of the frequency of sleep arousals. The respiratory airflow signal in an inner loop of the control algorithm is monitored to detect an airway obstruction. If the arousal index is high, then the sensitivity of obstruction detection and/or the aggressiveness of the treatment is increased, and if the arousal index is low, then the sensitivity of the obstruction detection and/or the aggressiveness of the treatment is decreased.