Method And Apparatus For Non-Invasive Monitoring Of Respiratory Parameters In Sleep Disordered Breathing

• US 20080066753A1
• Filed: 10/06/2005
• Published: 03/20/2008
• Est. Priority Date: 10/06/2004
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Oates, John, Martin, Dion
• Granted Patent: US 9,220,856 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/0826 Detecting or evaluating apnoea events A61B5/4818 takes precedence
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/42 Rate

Abstract

An air delivery system includes a controllable flow generator operable to generate a supply of pressurized breathable gas to be provided to a patient for treatment and a pulse oximeter configured to determine a measure of patient effort during a treatment period and provide a patient effort signal for input to control operation of the flow generator.

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24. A method for delivering positive pressure therapy by a CPAP ventilator to a patient having a health disorder comprising

analyzing a signal from a pulse oximeter to determine patient effort and forming a patient effort signal,

inputting the patient effort signal to a feedback controller of the ventilator that controls positive pressure therapy to the patient.

25. The method of delivering positive pressure therapy of claim 24 wherein the health disorder is sleep disordered breathing, congestive heart failure, or stroke.

26. The method of delivering positive pressure therapy of claim 24 wherein a pulse oximeter signal is processed to remove signals indicative of heart rate and leave signals indicative of respiratory rate.

27. The method of delivering positive pressure therapy of claim 26 wherein the processing employs a low pass filter, peak detector, nadir detector or averaging.

28. The method of delivering positive pressure therapy of claim 24 wherein in the absence of respiratory flow limitation, persistently high respiratory effort indicates inadequate pressure support.

29. The method of delivering positive pressure therapy of claim 24 wherein the effort information in a VPAP or AutoCS device is used to titrate applied PEEP.

30. The method of delivering positive pressure therapy of claim 24 wherein a measure of effort waveshape is used as an indicator that a patient has been overventilated.

31. The method of delivering positive pressure therapy of claim 30 further comprising the step of using the indicator to titrate the target ventilation.

32. The method of delivering positive pressure therapy of claim 24 further comprising the step of determining venous pulsation as an input to a CPAP algorithm for patients with OSA and heart failure.

33. The method of delivering positive pressure therapy of claim 24 further comprising the step of limiting the CPAP pressure applied in response to increases in venous pulsation.

34. The method of delivering positive pressure therapy of claim 24 further comprising the step of determining vascular compliance as an input to a CPAP algorithm.

35. The method of delivering positive pressure therapy of claim 34 wherein changes in vascular compliance are indicative of patient arousals.

36. The method of delivering positive pressure therapy of claim 35 further comprising the step of augmenting the data for prescribing CPAP levels.

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54. A therapy system for a patient having a pulse oximeter and receiving a flow of pressurized air via a patient interface, wherein a therapy algorithm receiving input of clinical targets determines a therapy pressure that a flow meter measures and communicates via an airflow signal to a signal processor, said processor inputting a first feedback signal to the therapy algorithm and wherein the pulse oximeter emits a photo-plethysmograph signal to a signal processor that inputs a second feedback signal to the therapy algorithm, wherein the therapy algorithm adjusts a level of PEEP/CPAP or a level of pressure support received by the patient.

55. The therapy system of claim 54, wherein the first feedback signal is selected from the group consisting of minute ventilation estimate, inspiratory airflow limitation, expiratory airflow limitation, tidal volume, leak, cardiac timing and respiratory phase.

56. The therapy system of claim 54, wherein the second feedback signal is selected from the group consisting of a relative indication of respiratory effort, an absolute indication of respiratory rate, patterns of respiratory effort and rate indicative of respiratory control anomalies or apnea type, an indication of respiratory rate, relative indication of worsening cardiac function, relative indication of venous congestion, relative variation in sympathetic nervous system activity, standard pulse oximetry, arrival time of systolic pulse at periphery, and pulse rate.

57. The therapy system of claim 54, wherein the clinical targets are selected from the group consisting of minimum ventilation, nominal ventilation, optimal synchrony, sleep quality, long-term cardiac function, anticipation/prediction of cardiac decompensation, minimum CPAP/EEP/PEEP, maximum CPAP/EEP/PEEP, minimum pressure support, maximum pressure, and maximum average pressure.

61. The therapy system of claim 54 for patients suffering general respiratory insufficiency, wherein the algorithm defines when pressure support, or End Expiratory Pressure (EEP) should be varied.

64. The therapy system of claim 54, wherein therapy rate settings are initialized based on respiratory rate information.

65. The therapy system of claim 54, wherein therapy trigger threshold settings, are initialized based on positively identifying cardiogenic flow amplitude.

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