초록 ▼

A pressure support system and method of treating disordered breathing that optimizes the pressure delivered to the patient to treat the disordered breathing while minimizing the delivered pressure for patient comfort. The controller in the pressure support system operates as a set of prioritized con

A pressure support system and method of treating disordered breathing that optimizes the pressure delivered to the patient to treat the disordered breathing while minimizing the delivered pressure for patient comfort. The controller in the pressure support system operates as a set of prioritized control layers, wherein each control layer competes for control of the pressure generating system to implement a unique pressure control process. The pressure support system also controls the pressure provided to the patient based on the variability of the monitored data and a trend analysis of this data, including an indication of the skewness of the patient's inspiratory waveform.

대표청구항 ▼

What is claimed is: 1. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted

What is claimed is: 1. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient; a monitoring system associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a pressure at a patient's airway, a flow of gas in such a patient's airway, or both and to output a pressure signal, a flow signal indicative thereof, respectively, or both; and a controller coupled to the monitoring system and the pressure generating system, for controlling a pressure of the flow of breathing gas output by the pressure generating system based on the output of the monitoring system, wherein the controller is programmed to operate according to one control layer in a set of prioritized control layers, wherein each control layer in the set of prioritized control layers competes for control of the pressure generating system with the other control layers, and wherein each control layer implements a unique pressure control process for controlling the pressure of the flow of breathing gas output by the pressure generating system. 2. The system of claim 1, wherein each control layer in the set of prioritized control layer includes: a detection module that receives the pressure signal, the flow signal or both; a monitoring module that monitors an output of the detection module to determine whether to request that the control layer take control of the pressure generating system; and a control module that control the operation of the pressure generating system responsive to the control layer being granted control thereof. 3. The system of claim 1, wherein the set of prioritized control layers include: (a) flow limit control layer that monitors the flow signal to determine whether the pressure generating system is exhibiting a large leak indicative of the patient circuit not being connected to an airway of a patient, and causes the pressure generating system to lower the pressure of the flow of breathing gas responsive to detection of the large leak and maintains the pressure generating system at the lower pressure; (b) snore control layer that monitors the flow signal, the pressure signal, or both for snoring, and causes the pressure generating system to increase the pressure of the flow of breathing gas responsive to detection of snore; (c) a big leak control layer that monitors the flow signal to determine whether the pressure generating system is exhibiting a leak that is less than the large leak but great enough to cause the pressure support system to not operate reliably, and causes the pressure generating system to lower the pressure of the flow of breathing gas responsive to detection of the large leak for predetermined period of time; (d) an apnea/hypopnea control layer that monitors the flow signal, the pressure signal, or both to determine whether the patient is experiencing an apnea, a hypopnea, or both, and causes the pressure generating system to adjust the pressure of the flow of breathing gas responsive to detection of apnea, hypopnea or both; (e) a variable breathing control layer that monitors the flow signal to determine whether the patient is experiencing erratic breathing, and causes the pressure generating system to adjust the pressure of the flow of breathing gas responsive to detection of erratic breathing; and (f) an auto-CPAP control layer that controls the pressure of the flow of breathing gas responsive to proactively search for a pressure that optimizes the pressure provided to the patient to treat disordered breathing. 4. The system of claim 3, wherein: (1) the flow limit control layer has a higher priority than the snore control layer, the big leak control layer, the apnea/hypopnea control layer, the variable breathing control layer, and the auto-CPAP control layer; (2) the snore control layer has a higher priority than the big leak control layer, the apnea/hypopnea control layer, the variable breathing control layer, and the auto-CPAP control layer and has a lower priority than the flow limit control layer; (3) the big leak control layer has a higher priority than the apnea/hypopnea control layer, the variable breathing control layer, and the auto-CPAP control layer and has a lower priority than the flow limit control layer and the snore control layer; (4) the apnea/hypopnea control layer has a higher priority than the variable breathing control layer, and the auto-CPAP control layer and has a lower priority than the flow limit control layer, the snore control layer and the big leak control layer; and (5) the variable breathing control layer has a higher priority than the auto-CPAP control layer and has a lower priority than the flow limit control layer, the snore control layer, the big leak control layer, and the apnea/hypopnea control layer. 5. The system of claim 1, further comprising a manual input for controlling the operation of the pressure support system, and wherein the set of prioritized control layers include at least one first control layer that is initiated based on the manual input and at least one second control layer that is initiated based on the pressure signal, the flow signal or both, wherein the at least one first control layer has a higher priority than the at least one second control layer. 6. The system of claim 5, wherein the first control layer is a ramp control layer that causes the pressure generating system to gradually increase the pressure of the flow of breathing gas from a relatively low level to a target level responsive to receipt of a ramp activation signal as the manual input. 7. The system of claim 6, wherein the second control layer includes at least one of the following control layers: (a) flow limit control layer that monitors the flow signal to determine whether the pressure generating system is exhibiting a large leak indicative of the patient circuit not being connected to an airway of a patient, and causes the pressure generating system to lower the pressure of the flow of breathing gas responsive to detection of the large leak and maintains the pressure generating system at the lower pressure; (b) snore control layer that monitors the flow signal, the pressure signal, or both for snoring, and causes the pressure generating system to increase the pressure of the flow of breathing gas responsive to detection of snore; (c) a big leak control layer that monitors the flow signal to determine whether the pressure generating system is exhibiting a leak that is less than the large leak but great enough to cause the pressure support system to not operate reliably, and causes the pressure generating system to lower the pressure of the flow of breathing gas responsive to detection of the large leak for predetermined period of time; (d) an apnea/hypopnea control layer that monitors the flow signal, the pressure signal, or both to determine whether the patient is experiencing an apnea, a hypopnea, or both, and causes the pressure generating system to adjust the pressure of the flow of breathing gas responsive to detection of apnea, hypopnea or both; (e) a variable breathing control layer that monitors the flow signal to determine whether the patient is experiencing erratic breathing, and causes the pressure generating system to adjust the pressure of the flow of breathing gas responsive to detection of erratic breathing; and (f) an auto-CPAP control layer that controls the pressure of the flow of breathing gas responsive to actively search for a pressure that optimizes the pressure provided to the patient to treat disordered breathing. 8. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient; a monitoring system associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a flow of gas in such a patient's airway and to output a flow signal indicative thereof; and a controller coupled to the monitoring system and the pressure generating system, for controlling the pressure generating system based on the output of the monitoring system, wherein the controller determines a breathing parameter from the flow signal, wherein the controller analyzes a variability of the breathing parameter and controls the pressure generating system based on a result of the variability analysis, and wherein analyzing the variability of the breathing parameter includes calculating a weighted peak flow and a best-fit trend line for the weighted peak flow over a plurality of breathing cycles, and calculating a variable breathing number (VB#) as follows: wherein the standard deviation is calculated as a standard deviation of the weighted peak flows over a plurality of breathing cycles from the best-fit trend line, and wherein the adjusted mean flow is determined based on an actual patient flow determined from the flow signal. 9. The system of claim 8, wherein a relationship between the adjusted mean flow and the actual patient flow varies based on the flow signal. 10. The system of claim 8, wherein the controller compares the variable breathing number to a first threshold and causes the pressure generating system to control the pressure of the flow of breathing gas as follows responsive to the variable breathing number exceeding the first threshold: (1) maintain the pressure at a constant level if the pressure of the flow of breathing gas was not increasing or decreasing when variability of the breathing parameter is detected; (2) decrease the pressure if the pressure of the flow of breathing gas was increasing when variability of the breathing parameter is detected; and (3) increase the pressure if the pressure of the flow of breathing gas was decreasing when variability of the breathing parameter is detected. 11. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient; a monitoring system associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a flow of gas in such a patient's airway and to output a flow signal indicative thereof; and a controller coupled to the monitoring system and the pressure generating system, for controlling the pressure generating system based on the output of the monitoring system, wherein the controller determines a skewness of a patient's inspiratory waveforms from the output of the flow sensor and controls the pressure generating system according to the skewness determination, and wherein the controller determines the skewness of the inspiratory waveform by segmenting the inspiratory waveform into a first region that corresponds to a beginning portion of the inspiratory waveform and a second region that corresponds to a middle portion of the inspiratory waveform, and comparing the flow in the second region to the flow in the first region. 12. The system of claim 11, wherein the flow in the first region corresponds to an average of the highest rates of flow in the first region, and wherein the flow in the second region corresponds to an average of the highest rates of flow in the second region. 13. The system of claim 11, wherein the first region corresponds to approximately a first third of the inspiratory waveform and the second region corresponds to approximately a second third of the inspiratory waveform, and wherein the highest flow rates in the first region and the second region are defined as the flow rates within 5% of the highest flow rates in each region. 14. The system of claim 11, wherein the skewness is calculated as a skewness number follows: 15. The system of claim 14, wherein the controller causes the pressure generating system to increase the pressure of the flow of breathing gas responsive to a decrease in the skewness number. 16. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient; a monitoring system associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a flow of gas in such a patient's airway and to output a flow signal indicative thereof; and a controller coupled to the monitoring system and the pressure generating system, for controlling the pressure generating system based on the output of the monitoring system, wherein the controller is programmed determine whether the patient is experiencing a central apnea/hypopnea or an obstructive/restrictive apnea/hypopnea by monitoring one or more of the following: (1) at least one shape parameter associated with the flow of gas during an apnea/hypopnea period, and (2) a characteristic of the flow of gas at the end of the apnea/hypopnea period indicative of an increase in respiratory effort, wherein the shape parameters monitored by the controller during an apnea/hypopnea period include a flatness of an inspiratory portion of a flow waveform, a roundness of the inspiratory portion of the flow waveform, a skewness of the inspiratory portion of the flow waveform, and wherein the controller considers a patient to be experiencing an obstructive/restrictive apnea/hypopnea responsive to the inspiratory portion of the flow waveform exhibiting at least one of an increase in flatness, a decrease in roundness, and an increased skewness, otherwise the controller considers the patient to be experiencing a central apnea/hypopnea, and wherein the controller prevents a pressure increase by the pressure generating system responsive to a determination that the patient is experiencing a central apnea/hypopnea. 17. The system of claim 16, wherein the characteristic of the flow of gas at the end of the apnea/hypopnea period is a volume or a peak flow related characteristic, wherein the controller considers a patient to be experiencing an obstructive/restrictive apnea/hypopnea responsive to the volume or the peak flow related characteristic at the end of the apnea/hypopnea period exceeding a predetermined threshold, otherwise the controller considers the patient to be experiencing a central apnea/hypopnea, and wherein the controller prevents a pressure increases by the pressure generating system responsive to a determination that the patient is experiencing a central apnea/hypopnea. 18. An auto-titration pressure support system comprising: a pressure generating system adapted to generate a flow of breathing gas at a selectable pressure level; a patient circuit having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient; a monitoring system associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a pressure at a patient's airway, a flow of gas in such a patient's airway, or both and to output a pressure signal, a flow signal indicative thereof, respectively, or both; and a controller coupled to the monitoring system and the pressure generating system, for controlling the pressure generating system based on the output of the monitoring system, wherein the controller is programmed to: (1) determine whether the patient is experiencing an apnea/hypopnea based on the pressure signal or the flow signal, (2) set a pressure treatment limit based on a pressure at a time an apnea/hypopnea is detected, (3) cause the pressure generating system to increase a pressure of the flow of breathing gas delivered to a patient responsive to a current pressure being below the pressure treatment limit, and (4) cause the pressure generating system to decrease a pressure of the flow of breathing gas delivered to a patient responsive to a current pressure being at or above the pressure treatment limit.