초록 ▼

A system for circuit compliance compensated volume assurance pressure control in a patient respiratory ventilation circuit, having a patient circuit volume estimator for estimating a patient circuit compliance, a patient circuit volume estimator to estimate a circuit volume VOLCKT—EST based on the p

A system for circuit compliance compensated volume assurance pressure control in a patient respiratory ventilation circuit, having a patient circuit volume estimator for estimating a patient circuit compliance, a patient circuit volume estimator to estimate a circuit volume VOLCKT—EST based on the patient circuit compliance, a patient volume observer, for estimating a patient volume VOLTID—EST based on a measure delivered net volume VOLNET and the patient circuit compliance, a volume assurance controller for generating a circuit compliance volume compensation factor VOLTID—CTL based on a preset assured volume VOLASS—SET and the estimated patient volume VOLTID—EST, and a decelerating inspiratory flow controller, operative to generate a decelerating inspiratory peak flow based on a preset inspiratory time TINSP and the volume compensation factor VOLTID—CTL.

대표청구항 ▼

1. A circuit compliance compensated volume assured pressure control system, comprising: a circuit compliance estimator, operative to estimate a patient circuit compliance;a patient circuit volume estimator, operative to estimate a circuit volume VOLCKT—EST based on the patient circuit compliance and

1. A circuit compliance compensated volume assured pressure control system, comprising: a circuit compliance estimator, operative to estimate a patient circuit compliance;a patient circuit volume estimator, operative to estimate a circuit volume VOLCKT—EST based on the patient circuit compliance and a patient estimated pressure Py;a patient volume observer, operative to estimate a patient volume VOLTID—EST based on a measure delivered net volume VOLNET and the patient circuit compliance;a volume assurance controller, operative to generate a circuit compliance volume compensation factor VOLTID—CTL based on a preset assured volume VOLASS—SET and the estimated patient volume VOLTID—EST, anda decelerating inspiratory flow corrector, operative to generate a decelerating inspiratory flow command based on a preset inspiratory time TINSP, the volume compensation factor VOLTID—CTL and a preset assured volume VOLASS—SET. 2. The system of claim 1, further comprising: a sensor processor operative to generate and to output the machine delivered net volume VOLNET;a netflow QNET integrator operative to integrate a net flow QNET value defined as by finding a difference between a measured inspiratory flow QINSP and a measured expiratory flow QEXP. 3. The system of claim 2, wherein said machine delivered net volume VOLNET is updated and reset at the start of the every inspiratory phase. 4. The system of claim 2, wherein: the estimated circuit volume VOLCKT—EST, and the estimated patient volume VOLTID—EST are updated; andthe measured machine delivered net volume VOLNET is reset at the start of an expiratory phase following an inspiratory phase during which a net flow QNET crosses zero;wherein the system further comprises:a netflow QNET zero crossing detector operative to detect a zero-crossing; anda QNET finder operative to find QNET by taking a difference between a measured inspiratory flow QINSP and a measured expiratory flow QEXP after said zero-crossing has been detected. 5. The system of claim 4, wherein when the net flow QNET does not cross zero during the inspiratory phase, the estimated circuit and patient volumes VOLCKT—EST and VOLTID—EST are updated; andthe measured machine delivered net volume VOLNET is reset when the net flow QNET crosses zero after the expiratory phase starts or when the expiratory phase has started over a predetermined period of time before the net flow QNET zero-crossing is detected. 6. The system of claim 1, wherein the volume assurance controller further comprises a gain scheduler: wherein the assurance controller is operative to generate a dynamic gain KVTID for weighting a volume error VOLTID—ERR between the preset assured volume VOLASS—SET and the estimated patient volume VOLTID—EST; andadd the volume compensation factor VOLTID—CTL to the weighted volume error KVTID multiplied with the VOL TID ERR after each breath. 7. The system of claim 6, wherein the volume assurance controller further comprises a volume error percentage converter for converting the volume error VOLTID—ERR into an error percentage VOLPCT_ERR⁢⁢by⁢⁢VOLPCT_ERR=VOLTID_ERRVOLASS_SET×100⁢%, so as to compute the dynamic gain KVTID as a function thereto. 8. The system of claim 7, wherein the volume assurance controller further comprises: a multiplier for multiplying the dynamic gain KVTID with the preset assured volume VOLASS—SET. 9. The system of claim 8, wherein the volume assurance controller further comprises an integrator operative to provide the volume compensation factor for a current breath by adding an output of the product of KVTID and VOLASS—SET with the volume compensation factor VOLTID—CTL obtained from a previous breath. 10. The system of claim 9, wherein the integrator is operative to receive an initialized value INICKT—VOL of the volume compensation factor VOLTID—CTL for a first breath of ventilation. 11. The system of claim 6 wherein the volume assurance controller further comprises a volume restrictor operative to prevent the volume compensation factor VOLTID—CTL exceeding a safety range from being output. 12. The system of claim 1, further comprising a volume limiter operative to limit the volume compensation factor VOLTID—CTL output from the volume assurance controller according to a patient volume VOLTID—Y measured from a Y flow sensor. 13. The system of claim 12, wherein before the measured patient volume VOLTID—Y reaches the preset assured volume VOLASS—SET and the circuit compliance compensation is disabled, the volume limiter is operative to control the volume assurance controller to output the volume compensation factor using: a) a volume error computer operative for computing a volume error VOLTID—ERR by a difference between the assured volume VOLASS—SET preset for a current breath and the patient volume VOLTID—EST estimated from a previous breath;b) a volume compensation factor computer operative for computing the volume compensation factor of the current breath by adding the volume error VOLTID—ERR to the volume compensator factor obtained from the previous breath; andc) a volume compensation factor limiter operative for limiting the volume compensation factor of the current breath between a maximum and minimum value. 14. The system of claim 13, wherein when the measured patient volume VOL TID—Y reaches the preset assured volume VOLASS SET, the volume assurance controller is operative to output the volume compensation factor VOLTID—CTL obtained from the previous breath. 15. The system of claim 1, wherein the decelerating inspiratory flow corrector is operative to compute a maximum inspiratory peak flow QINSP—PEAK by: QINSP_PEAK=4/3*(VOLASS_SETk+VOLTID_CTLk)*60TINSP_SETk. 16. The system of claim 15, wherein the decelerating inspiratory flow corrector is operative to compute a modulated decelerating inspiratory flow QINSP—SET by: QINSP_SET=QINSP_PEAK-TINSPk*QINSP_PEAK2*TINSP_SETk. 17. A system for circuit compliance compensated volume assured pressure control in a patient ventilation circuit, comprising: a volume assurance controller operative to provide an estimated circuit compliance volume compensation factor VOLTID—CTL based on a patient estimated pressure Py, an estimated or measured patient volume, VOLTID—EST or VOLTID—Y, and a preset assured volume VOLASS—SET; anda decelerating inspiratory flow corrector operative to modulate an inspiratory flow QINSP—SET based on a preset waveform, a preset inspiratory time TINSP—SET, a preset assured volume VOLASS—SET and the volume compensation factor VOLTID—CTL output from the volume assurance controller. 18. The system of claim 17, further comprising a patient volume observer operative to provide the estimated patient volume VOLTID—EST from a measured machine delivered net volume VOLNET. 19. The system of claim 18, wherein the measured machine delivered net volume VOLNET integrated from a net flow QNET defined as a flow difference between a measure inspiratory flow QINSP and a measured expiratory flow QEXP. 20. The system of claim 18, further comprising a circuit volume estimator operative to provide an estimated circuit volume VOLCKT—EST according to an estimated circuit compliance. 21. The system of claim 20, wherein the patient volume estimator is operative to subtract the estimated circuit volume VOLCKT—EST from the measured machine delivered net volume VOLNET as the estimated patient volume VOLTID—EST and output the estimated patient volume VOLTID—EST to the volume assurance controller. 22. The system of claim 17, further comprising: a patient flow sensor operative to provide the measured patient volume VOLTID—Y; anda measured patient volume integrator operative to integrate the measured patient volume producing a patient flow Qy. 23. The system of claim 17, wherein the volume assurance controller further comprises a gain scheduler operative to provide a weighting gain KVTID as a function of a volume percentage VOLPCT—ERR, —wherein the volume percentage VOLPCT—ERR is defined as an absolute value of a volume error VOLTID—EST between a preset assured volume VOLASS—SET and the estimated or measured patient volume VOLTID—EST or VOLTID—Y divided by the preset assured volume VOLASS—SET. 24. The system of claim 23, wherein the volume compensation factor VOLTID—CTL is initialized with an initial value INICKT—VOL at a first breath of ventilation provided by the patient ventilation circuit. 25. The system of claim 24, wherein the volume assurance controller further comprises a multiplier for multiplying the weighting gain KVTID with the volume error VOLTID—ERR. 26. The system of claim 25, wherein the volume assurance controller further comprises an integrator operative to add an output of the multiplier with the volume compensation factor VOLTID—CTL obtained from a previous breath. 27. The system of claim 17, wherein the decelerating inspiratory flow corrector is operative to compute a maximum peak inspiratory flow QINSP—PEAK by: QINSP_PEAK=4/3*(VOLASS_SETk+VOLTID_CTLk)*60TINSP_SETk. 28. The system of claim 27, wherein the decelerating inspiratory flow corrector is operative to compute a modulated decelerating inspiratory flow QINSP—SET by: QINSP_SETk=QINSP_PEAKk-TINSPk*QINSP_PEAKk2*TINSP_SETk 29. A patient respiratory ventilation circuit, comprising: a ventilator, operative to provide an inspiratory gas to and receive an expiratory gas from a patient via a patient circuit;a system for circuit compliance compensated volume assured pressure control, comprising:a volume assurance controller operative to provide an estimated circuit compliance volume compensation factor VOLTID—CTL based on an estimated or measured patient volume, VOLTID—EST or VOLTID—Y, and a preset assured volume VOLASS—SET, anda decelerating inspiratory flow corrector operative to modulate an inspiratory flow QINSP—SET based on a preset waveform, a preset inspiratory time TINSP—SET, a preset assured volume VOLASS—SET, and the volume compensation factor VOLTID—CTL output from the volume assurance controller; anda servo control subsystem operative to control a flow control valve and an exhalation valve of the ventilator according to the preset waveform, the preset inspiratory time TINSP—SET, and the larger amount between the inspiratory flow QINSP—SET modulated by the decelerating inspiratory flow corrector and an inspiratory pressure controller flow QINSP—PRSCTL. 30. The circuit of claim 29, wherein the volume assured pressure control system further comprises a patient volume observer operative to provide the estimated patient volume VOLTID—EST from a measured machine delivered net volume VOLNET. 31. The circuit of claim 30, wherein the measured machine delivered net volume VOLNET is integrated from a net flow QNET defined as a flow difference between a measure inspiratory flow QINSP and a measured expiratory flow QEXP. 32. The circuit of claim 31, wherein the volume assured pressure control system further comprises a circuit volume estimator operative to provide an estimated circuit volume VOLCKT—EST according to an estimated circuit compliance. 33. The circuit of claim 32, wherein the patient volume estimator is operative to subtract the estimated circuit volume VOLCKT—EST from the measured machine delivered net volume VOLNET as the estimated patient volume VOLTID—EST and output the estimated patient volume VOLTID—EST to the volume assurance controller. 34. The circuit of claim 29, wherein the volume assured pressure control system further comprises a patient flow sensor operative to provide the measured patient volume VOLTID—Y by integrating a patient flow Qy measured thereby. 35. The circuit of claim 29, wherein the volume assurance controller further comprises a gain scheduler operative to provide a weighting gain KVTID as a function of a volume percentage VOLPCT—ERR, wherein the volume percentage VOLPCT—ERR is defined as an absolute value of a volume error VOLTID—ERR between a preset assured volume VOLASS—SET and the estimated or measured patient volume VOLTID—EST or VOLTID—Y divided by the preset assured volume VOLASS—SET. 36. The circuit of claim 35, wherein the volume compensation factor VOLTID—CTL is initialized with an initial value INICKT—VOL at a first breath of ventilation provided by the patient ventilation circuit. 37. The circuit of claim 36, wherein the volume assurance controller further comprises a multiplier for multiplying the weighting gain KVTID with the volume error VOLTID—ERR. 38. The circuit of claim 37, wherein the volume assurance controller further comprises an integrator operative to add an output of the multiplier with the volume compensation factor VOLTID—CTL obtained from a previous breath. 39. The circuit of claim 29, wherein the decelerating inspiratory flow corrector is operative to compute a maximum peak inspiratory flow QINSP—PEAK by: QINSP_PEAKK=4/3*(VOLASS_SETk+VOLTID_CTLk)*60TINSP_SETk 40. The circuit of claim 29, wherein the decelerating inspiratory flow corrector is operative to compute an a modulated decelerating inspiratory flow QINSP—SET by: QINSP_SETk=QINSP_PEAKk-TINSPk*(QINSP_PEAKk2*TINSP_SETk). 41. The circuit of claim 29, wherein the servo control subsystem further comprises: an inspiratory pressure servo controller operative to output an inspiratory pressure controller flow QINSP—PRSCTL computed based on an error between a preset inspiratory pressure PRSINSP—SET captured at the beginning of every breath and a measured patient pressure Py,a comparator operative to output a final inspiratory flow QINSP—DES from the larger amount between the modulated decelerating inspiratory flow QINSP—SET and the inspiratory pressure controller flow QINSP—PRSCTL;an inspiratory flow servo controller operative to receive the final inspiratory flow QINSP—DES and a preset maximum allowable inspiratory flow QINSP—MAX to generate a flow control valve signal FCVDIA according to the final inspiratory flow QINSP—DES restricted under the preset maximum allowable inspiratory flow QINSP—MAX; andan exhalation pressure servo controller operative to open or close the exhalation valve of the ventilator. 42. The circuit of claim 41, wherein the exhalation pressure servo controller is operative to open or close the exhalation valve according to an exhalation valve pressure command PRSEXH—DES. 43. The method of claim 42, further comprising: d) initializing the circuit compliance pressure compensation factor VOLTID—CTL to the initial value INICKT—VOL when any user setup parameter of the ventilation system is changed. 44. The method of claim 43, wherein when the estimated patient volume VOLTID—EST is selected for generating the volume compensation factor VOLTID—CTL, step (a) further comprises: a1) providing a machine delivered net flow QNET by computing a flow differential of a measured inspiratory flow QIWSP and a measured expiratory flows QEXP; anda2) integrating the machine delivery net flow QNET into the machine delivered net volume VOLNET. 45. The method of claim 44, wherein when the net flow QNET is detected to cross zero during an inspiratory phase, at the start of an expiratory phase following the inspiratory phase, the estimated circuit volume VOLCKT—EST and the estimated patient volume VOLTID—EST are updated, and the measured machine delivered net volume VOLNET is reset. 46. A method for circuit compliance compensated volume assurance pressure control in a patient respiratory ventilation system, comprising: a) measuring a patient volume VOLTID—Y through a flow sensor installed at a patient piece of a patient circuit in the ventilation system, or estimating a patient volume VOLTID—EST based on a machine delivered net volume VOLNET and a circuit compliance CT of the patient circuit; andb) predetermining an initial value INICKT—VOL for a circuit compliance volume compensation factor VOLTID—CTL and updating the volume compensation factor VOLTID—CTL based on a preset assured volume VOLASS—SET and the patient volume VOLTID—Y or VOLTID—EST for each breath; andc) generating an inspiratory flow QINSP—SET according to a predetermined waveform, a preset inspiratory time TINSP, a preset assured volume VOLASS—SET, and the volume compensation factor VOLTID—CTL. 47. The method of claim 46, further comprising a step of resetting and updating the measured patient volume VOLTID—Y and/or the measured machine delivered net volume VOLNET at the beginning of every inspiratory phase. 48. The method of claim 47, wherein step (a) further comprising: a3) deriving a relationship between circuit pressure Py and circuit volume Vcc from the circuit compliance CT;a4) estimating a circuit volume VOLCKT—EST from the relationship by providing a measured patient circuit Py; anda5) subtracting the estimated circuit volume VOLCKT—EST from the measured machine delivered net volume VOLNET to obtain the estimated patient volume VOLTID—EST. 49. The method of claim 48, wherein when the net flow QNET does not cross zero during an inspiratory phase, the estimated circuit volume VOLCKT—EST and the estimated patient volume VOLTID—EST are updated, and the measured machine delivered net volume VOLNET is reset at the earlier when the net flow QNET crosses zero after the expiratory phase starts or when the expiratory phase has started over a predetermined period of time before the net flow QNET has crossed zero. 50. The method of claim 49, wherein step (b2) further comprising multiplying the gain KVTID with the volume error VOLTID—ERR to obtain the volume correction. 51. The method of claim 50, wherein step (b) further comprising: b4) limiting the updated circuit compliance volume compensation factor between a predetermined allowable range. 52. The method of claim 46, wherein step (b) further comprises: b1) computing a volume error percentage VOLPCT—ERR defined as a ratio of an absolute value of a volume error VOLTID—ERR to a preset assured volume VOLASS—SET, wherein the volume error VOLTID—ERR is a volume differential between the preset assured volume VOLASS—SET and the patient volume VOLTID—Y or VOLTID—EST;b2) determining a gain KVTID as a function of the volume error percentage VOLPCT ERR, so as convert the volume error VOLTID ERR into a volume correction for the circuit compliance volume compensation factor VOLTID—CTL; andb3) updating the circuit compliance volume compensation factor VOLTID—CTL by adding the volume correction thereto. 53. The method of claim 46, wherein step (c) further comprises: c1) computing a maximum peak flow QINSP PEAK by: QINSP_PEAKK=4/3*(VOLASS_SETk+VOLTID_CTLk)*60TINSP_SETk;andc2) computing a modulated decelerating inspiratory flow by: QINSP_SETk=QINSP_PEAKk-TINSPk*QINSP_PEAKk2*TINSP_SETk 54. The method of claim 46, further comprising: d1) capturing a preset inspiratory pressure PRSINSP—SET at the beginning of every breath;d2) generating an inspiratory pressure controller flow QINSP—PRSCTL based on an error between the preset inspiratory pressure PRSINSP—SET and a measured patient pressure Py;d3) selecting a larger amount between the inspiratory pressure controller flow QINSP—PRSCTL and the modulated decelerating inspiratory flow QINSP—SET to determine a flow control valve command FCVDIA. 55. The method of claim 54, further comprising a step of generating an exhalation valve command to control open/close status of an exhalation valve. 56. The method of claim 55, further comprising a step of closing the exhalation valve during an inspiratory phase.