Apparatus and method for controlling gas-delivery mechanism for use in respiratory ventilators
First Claim
1. A method for controlling a gas-delivery mechanism of a mechanical ventilator which supplies a bas containing oxygen having an assisting gas pressure Pvent corresponding to patient'"'"'s respiratory effort pressure Pmus, the method comprising:
- a flow-rate measuring step of measuring a flow rate F of an assisting gas supplied to a patient'"'"'s respiratory airway;
a flow-rate estimation step of estimating a flow rate {circumflex over (F)} of an assisting gas to be supplied to the patient'"'"'s respiratory airway when the assisting gas having an assisting gas pressure Pvent is supplied to the patient'"'"'s respiratory airway, with the aid of flow-rate estimation means in which a patient'"'"'s respiratory system is modeled;
a difference calculation step of calculating a flow-rate difference Δ
F between the measured flow rate F and the estimated flow rate {circumflex over (F)}; and
a control value calculation step of calculating the target pressure Pin, based on the flow-rate difference Δ
F and providing a signal representing the target pressure Pin, to the gas-delivery mechanism.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of controlling a mechanical ventilator is provided which is capable of increasing a stability margin in the controlling of a gas-delivery mechanism for the mechanical ventilator. The flow rate F of an assisting gas is measured, and an observer 54 estimates a flow rate {circumflex over (F)} of the assisting gas. A difference ΔF between the measured flow rate F and estimated flow rate {circumflex over (F)} is then determined, and information on a patient'"'"'s respiratory effort pressure Pmus is obtained. A target pressure Pin for controlling a gas-delivery mechanism 20 is calculated on the basis of this information. When the target pressure Pin is calculated on the basis of the flow-rate difference ΔF, an allowance with respect to the stability limit of the overall system 14 can be increased. This enables the runaway to rarely occur even when an actual overall system is varied. Moreover, the responsibility of assist respiration can be improved as compared with that of the related art PAV method.
39 Citations
18 Claims
-
1. A method for controlling a gas-delivery mechanism of a mechanical ventilator which supplies a bas containing oxygen having an assisting gas pressure Pvent corresponding to patient'"'"'s respiratory effort pressure Pmus, the method comprising:
-
a flow-rate measuring step of measuring a flow rate F of an assisting gas supplied to a patient'"'"'s respiratory airway;
a flow-rate estimation step of estimating a flow rate {circumflex over (F)} of an assisting gas to be supplied to the patient'"'"'s respiratory airway when the assisting gas having an assisting gas pressure Pvent is supplied to the patient'"'"'s respiratory airway, with the aid of flow-rate estimation means in which a patient'"'"'s respiratory system is modeled;
a difference calculation step of calculating a flow-rate difference Δ
F between the measured flow rate F and the estimated flow rate {circumflex over (F)}; and
a control value calculation step of calculating the target pressure Pin, based on the flow-rate difference Δ
F and providing a signal representing the target pressure Pin, to the gas-delivery mechanism. - View Dependent Claims (2)
-
-
3. A control apparatus for controlling a gas-delivery mechanism of a mechanical ventilator which supplies a gas containing oxygen having an assisting gas pressure Pvent corresponding to patient'"'"'s respiratory effort pressure Pmus, the method comprising:
-
flow-rate measuring means for measuring a flow rate F of an assisting gas to be supplied to a patient'"'"'s respiratory airway;
flow-rate estimation means for estimating a flow-rate {circumflex over (F)} of an assisting gas to be supplied to the patient'"'"'s respiratory airway when the assisting gas having an assisting gas pressure Pvent is supplied to the patient'"'"'s respiratory airway, in the flow rate estimation means a patient'"'"'s respiratory system being modeled;
difference calculation means for calculating a flow-rate difference Δ
F between the measured flow rate F and the estimated flow rate {circumflex over (F)}; and
control value calculation means for calculating the target pressure Pin based on the flow-rate difference Δ
F and providing a signal representing the target pressure Pin to the gas-delivery mechanism. - View Dependent Claims (4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18)
-
-
6. The control apparatus of 3, wherein the control value calculation means determines a first calculation value (KFG·
- Δ
F) which is a product of a predetermined flow-rate gain KFG and the flow-rate difference Δ
F, and a second calculation value (KFG·
Δ
F/s) whish is a product of a predetermined volume gain KVG, and an integral of Δ
F, andthen adds the first calculation value (KFG·
Δ
F) and the second calculation value (KFG·
Δ
F/s) to calculate the target pressure Pin. - View Dependent Claims (17)
- Δ
-
11. A patient'"'"'s respiratory effort pressure estimation apparatus for estimating a patient'"'"'s respiratory effort pressure Pmus when an assisting gas containing oxygen is delivered to a patient'"'"'s respiratory airway with a predetermined assisting gas pressure Pvent, comprising:
-
flow-rate measuring means for measuring a flow rate {circumflex over (F)} of the assisting gas having been delivered to the patient'"'"'s respiratory airway;
flow-rate estimation means having a respiratory system model obtained by modeling a patient'"'"'s respiratory system, for estimating a flour rate {circumflex over (F)} of the assisting gas to be delivered to the patient'"'"'s respiratory airway when the assisting gas is delivered thereto with the assisting gas pressure Pvent;
difference calculation means for calculating a flow-rate difference Δ
F between the measured flow rate F and the estimated flow rate {circumflex over (F)}; and
respiratory effort pressure estimation means for estimating the patient'"'"'s respiratory effort pressure Pmus based on the flow-rate difference Δ
F.
-
Specification