Method and an apparatus for monitoring and controlling flows

Abstract

A method and an apparatus for monitoring and controlling flows in medical equipment including an anesthetic machine and a ventilator for influencing a patient's respiratory system are disclosed. The apparatus comprises a microprocessor and an airway system comprising drive gas conduits provided with an inhalation valve (2) and an exhalation valve (5) for gas discharging as well as a ventilator end flow sensor (3) for measuring the introduced or discharged drive gas flow through the valves. The airway system also comprises patient end breathing tubing in which a patient end flow sensor (11) for measuring the patient's inspired and expired gas flow is provided. By comparing the measured values of the two flow sensors against the characteristic curve of the inhalation valve (2), the microprocessor can judge the operation states and accuracy of the respective flow sensors and the inhalation valve (2).

Description

BRIEF DESCRIPTION THE DRAWINGS

FIG. 1 is a schematic diagram illustrating the principle of the airway of an apparatus for monitoring and controlling flows according to the present invention;

FIG. 2 is a system block diagram of an apparatus for monitoring and controlling flows according to the present invention;

FIG. 3 is a flow chart of the process for monitoring and controlling flows according to the present invention.

Claims

1. An apparatus for monitoring and controlling flows in medical equipment including an anesthetic machine and a ventilator for influencing a patient's respiratory system, said apparatus comprising a power supply, a microprocessor, an airway system, several microprocessor-controlled valve state monitoring units and valve actuating units and sensor data collecting and receiving units, said airway system comprising a bellows (4) and drive gas conduits at a ventilator end and breathing tubing at a patient end connected respectively to an outer chamber and a gasbag of the bellows (4); said drive gas conduits connecting a pressure-reducing valve (1), an inhalation valve (2) and an exhalation valve (5) for gas-discharging; said breathing tubing at the patient end comprising an inhaling conduit and an exhaling conduit; said inhalation valve (2) being connected to the corresponding valve state monitoring units and valve actuating units; said apparatus further comprising a ventilator end flow sensor (3) provided in the drive gas conduits and a patient end flow sensor (11) in the breathing tubing at the patient end, wherein output signals of the ventilator end flow sensor (3) and the patient end flow sensor (11) are delivered to the respective sensor data collecting and receiving units.

2. The apparatus for monitoring and controlling flows according to claim 1, wherein said patient end flow sensor (11) for measuring flows of inhaled and exhaled gases of the patient is either a two-way flow sensor installed following a Y-type connector connecting the patient end breathing tubing to the patient, or two one-way flow sensors are respectively installed in the inhaling conduit and the exhaling conduit.

3. The apparatus for monitoring and controlling flows according to claim 1, wherein said ventilator end flow sensor (3) is a two-way flow sensor installed in the drive gas conduit between the inhalation valve (2) and the bellows (4).

4. The apparatus for monitoring and controlling flows according to claim 1, wherein said ventilator end flow sensor (3) is a one-way flow sensor for measuring the introduced drive gas flow and for calibrating the patient end flow sensor (11) or the inhalation valve (2), said ventilator end flow sensor (3) being connected between the inhalation valve (2) and a junction where conduits of the exhalation valve (5) and the inhalation valve (2) are connected to each other.

5. A method for monitoring and controlling flows adapted for use in medical equipment including an anesthetic machine and a ventilator for influencing a patient's respiratory system, said equipment comprising a microprocessor, an airway system, several microprocessor-controlled valve state monitoring units and valve actuating units as well as sensor data collecting and receiving units, said airway system comprising drive gas conduits connecting an inhalation valve (2) and an exhalation valve (5) for gas-discharging as well as an equipment end flow sensor (3) for measuring the drive gas flow introduced or discharged through the inhalation valve and the exhalation valve; said airway system further comprising a patient end breathing tubing which is provided with a patient end flow sensor (11) for measuring flows of inspired and expired gases of the patient; said method comprising the following steps: A. the microprocessor actuates the airway system into an inhaling control period and an exhaling control period alternately through the valve actuating units;B. the microprocessor monitors control parameters of the inhalation valve (2) through the valve state monitoring units;C. the microprocessor acquires gas flow values monitored and measured by the equipment end flow sensor (3) and the patient end flow sensor (11) through the sensor data collecting and receiving units;D. the microprocessor analyzes and compares the control parameters with the respective gas flow values measured during a same inhaling control period or during a same exhaling control period, and carries out adjustment based on the analyzed and compared result.

6. The method for monitoring and controlling flows according to claim 5, wherein said control parameters include the gas flow that the inhalation valve (2) actually inhales during the inhaling control period, which is the integration of the gas delivering velocity and the gas delivering time through the inhalation valve.

7. The method for monitoring and controlling flows according to claim 5, wherein corresponding safety threshold values are determined for the deviations between the control parameters and the respective measured gas flow values as well as between the respective measured gas flow values themselves, according to the fresh gas flow values and the allowable range of error in the measurement of the respective sensors, said safety threshold values being applied to the analysis and comparison in step D.

8. The method for monitoring and controlling flows according to claim 6, wherein corresponding safety threshold values are determined for the deviations between the control parameters and the respective measured gas flow values as well as between the respective measured gas flow values themselves, said safety threshold values being applied to the analysis and comparison in step D.

9. The method for monitoring and controlling flows according to claim 7, wherein, in step D, the microprocessor carries out a closed-loop flow control taking the measured value of the patient end flow sensor (11) as the reference value, when it judges that the deviations between the control flow of the inhalation valve (2), the measured flow of the equipment end flow sensor (3) and the measured flow of the patient end flow sensor (11) are within the respective safety threshold values.

10. The method for monitoring and controlling flows according to claim 7, wherein, in step D, the microprocessor carries out a closed-loop flow control taking the measured value of the patient end flow sensor (11) as the reference value and prompts the user that the inhalation valve (2) needs to be calibrated, when it judges that the measured value of the equipment end flow sensor (3) and the measured value of the patient end flow sensor (11) are substantially equal, while the deviations between the control parameters and these measured values exceed the corresponding safe threshold values.

11. The method for monitoring and controlling flows according to claim 7, wherein, in step D, upon judging that the deviations between the measured flow of the equipment end flow sensor (3) and the measured flow of the patient end flow sensor (11) exceed the corresponding safety threshold values, the microprocessor compares firstly the control parameters of the inhalation valve (2) with the measured value of the patient end flow sensor (11) and, if the deviations are within the corresponding safety threshold values, carries out a closed-loop flow control taking the measured value of the patient end flow sensor (11) as the reference value; otherwise the microprocessor compares then the control parameters with the measured value of the equipment end flow sensor (3) and, if the deviations are within the corresponding safety threshold values, carries out a closed-loop flow control taking the measured value of the equipment end flow sensor (3) as the reference value.

12. An apparatus for monitoring and controlling flows adapted for use in medical equipment for influencing a patient's respiratory system, especially in an anesthetic machine and a ventilator, said apparatus comprising: an airway system, which comprises an inhalation valve (2) and an exhalation valve (5) installed in drive gas conduits, an equipment end flow sensor (3) for measuring the introduced and/or discharged drive gas flow through the inhalation valve (2) and/or the exhalation valve (5) and a patient end flow sensor (11) for measuring the patient's inspired and expired gas flow,valve state monitoring units and valve actuating units connected to the inhalation valve (2) and/or the exhalation valve (5),sensor data collecting and receiving units associated with the equipment end flow sensor (3) and the patient end flow sensor (11),a microprocessor for controlling the valve state monitoring units, the valve actuating units and the sensor data collecting and receiving units,wherein the microprocessor analyzes and compares the measured flow values of the equipment end flow sensor (3) and the patient end flow sensor (11) and with the control parameters of the inhalation valve (2) and/or the exhalation valve (5) and thereby determines and controls the operation states of the respective flow sensors and valves so as to control the flows accurately.