JP2002177397A - Medical gas flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor an oxygen inhalation state when a patient requiring the inhalation of oxygen inhales a proper amount of oxygen on a medical site. SOLUTION: A medical gas flowmeter is equipped with the flow rate sensor 1 arranged in a gas flow channel F to measure the flow rate of medical gas passing through the gas flow channel F from a gas supply source 33 toward a mask M, a sensor signal input means 3a for processing the sensor output inputted from the flow rate sensor to output a predetermined electric signal, a supply time measuring means 23 for measuring the supply time of the medical gas to the patient accompanied by the signal output from the sensor signal input means 3a, a supply judge means 23b for judging the completion of supply on the basis of the judgment of the supply of gas for a definite time and a control means 31a operating a gas supply cut-off valve on the basis of the judge result due to the supply judge means 23b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a patient who needs oxygen inhalation in a medical setting,
The present invention relates to a medical gas flow meter having a function of monitoring an oxygen inhalation state.

[0002]

2. Description of the Related Art Conventionally, when a nurse in a hospital gives oxygen to a patient, in order to inhale an appropriate amount of oxygen, a time corresponding to the amount of inhalation is measured using a commercially available timer separately from an oxygen inhaler. After setting, the user stopped the oxygen inhalation by listening to the electronic sound emitted from the timer as the set time elapsed.

[0003]

However, the conventional oxygen inhaler is a machine in which oxygen depressurized from an oxygen cylinder is humidified by passing it through a wetter through a pipe, and then oxygen is inhaled by a patient through an inhalation mask through a tube. Because of the formula, it was not possible to incorporate a timer that operates electrically. Therefore, it was necessary to separately prepare a timer.
In addition, since the end of the time measurement by the timer is determined by the electronic sound to stop the oxygen inhalation, the person in charge needs to be around the patient, and there is a problem that it is not possible to stably engage in other work. Furthermore, even if the oxygen supply is stopped for some reason before the end of timekeeping, or if the patient's condition suddenly changes and the oxygen inhalation becomes irregular, it is possible that the user will not notice an abnormal situation until the timer sounds the beep when the timekeeping ends. There is.

The present invention has been made to solve the above problems, and automatically stops oxygen intake by setting a timer, issues an alarm when an abnormality occurs, and automatically stops oxygen intake. It is an object of the present invention to provide a medical gas flow meter having a function that enables the following.

[0005]

As shown in FIG. 1, a medical gas flow meter according to the present invention is connected to a tube connected to an inhalation mask mounted on a patient, and is supplied to the patient from a gas supply source. A medical gas flowmeter for measuring a flow rate of a medical gas in an internal gas flow path, wherein the medical gas flow meter is disposed in the gas flow path and passes through the gas flow path from the gas supply source toward a mask. A flow sensor for measuring the flow rate of the gas for use, a sensor signal input means for processing a sensor output input from the flow sensor into a predetermined electric signal and outputting the signal, and a signal output from the sensor signal input means to the patient. Supply time measuring means for measuring the supply time of the medical gas, supply determining means for determining the end of supply based on gas supply determination for a fixed time, and gas supply based on the determination result by the supply determining means. It is obtained by a control means for actuating the supply shut-off valve.

According to the present invention, when the supply of medical gas to a patient is performed for a preset time, the control means is activated and the gas supply cutoff valve is operated to automatically cut off the gas. There is no need to constantly assign a medical staff, and the number of people can be reduced.

The medical gas flow meter according to the present invention measures the number of respirations of a patient wearing the inhalation mask based on the number of level changes per unit time of the signal output from the sensor signal input means. It is provided with a measuring means, a respiratory abnormality judging means for judging abnormal respiration when the number of breaths in the unit time is equal to or more than a set number of times, and an alarm means for issuing an alarm based on the respiratory abnormality judgment result.

According to the present invention, the breathing frequency of a patient at the time of gas inhalation is measured by a breathing frequency measuring means, and if the breathing abnormality determining means determines that the number of breathing times per unit time is equal to or greater than a set number, the alarm means By issuing an alarm at
A sudden change in the patient's condition during gas inhalation can be immediately detected.

The medical gas flow meter according to the present invention has a flow rate decrease measuring means for measuring a decrease in gas flow rate from the level of a signal output from a sensor signal input means, and a flow rate decrease for a preset time is recognized. When the flow rate is abnormal,
Flow rate abnormality determining means for activating the alarm means.

According to the present invention, a decrease in gas flow rate is measured by a flow rate decrease measuring means based on a signal level output from a sensor signal input means, and when the gas flow decrease is continuously recognized for a preset time, By determining the flow rate abnormality by the flow rate abnormality determining means and activating the alarm means, it is possible to detect the supply interruption of the medical gas at an early stage.

Each abnormality judging means of the medical gas flow meter according to the present invention judges a transient abnormality and makes an operation signal to the alarm means insignificant.

According to the present invention, if an abnormality is determined for a short time within the respiration frequency measurement time or the flow rate reduction measurement time due to mixing of a noise component into a sensor signal or the like, the abnormality is determined to be transient and an alarm is issued. By not operating the means, erroneous determination of an abnormality due to noise can be prevented.

Each abnormality judging means of the medical gas flow meter according to the present invention judges a transient abnormality, makes the operation signal to the alarm means insignificant, and returns the judging operation to the initial operation.

According to the present invention, when an abnormality is determined for a short time within the respiration frequency measurement time or the flow rate reduction measurement time when a noise component is mixed into a sensor signal, the abnormality is determined to be transient and an alarm is issued. Returning the respiratory frequency measurement time or flow rate reduction measurement time to the initial state without operating the means, and restarting the time measurement, monitoring the respiratory abnormality or flow abnormality without being affected by the occurrence of past abnormalities. Can be.

The medical gas flow meter according to the present invention performs the above-described respiratory abnormality determination and flow rate abnormality determination simultaneously with the measurement of the supply time of the medical gas.

According to the present invention, the determination of the respiratory abnormality and the determination of the abnormal flow rate are performed simultaneously with the measurement of the supply time of the medical gas. Moreover, it can be performed using the same equipment.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A medical gas flow meter according to the present invention will be described below with reference to the accompanying drawings. FIG. 2 is an explanatory view showing a use state of the medical gas flow meter according to the present invention. In the figure, a medical gas flow meter (hereinafter abbreviated as a flow meter) of the present invention indicated by reference numeral FM is an oxygen gas. The oxygen released from the cylinder 33 and decompressed by the decompressor G is humidified by a wetter M equipped with a flow control valve, and then supplied to the inhalation mask MS via the tube T. It is used by being interposed between the wetter M.

First Embodiment As shown in the front view of FIG. 3, a display unit DIS such as a liquid crystal display and a time setting for setting each operation time are provided on the front surface of the flow meter FM according to the first embodiment. Button PB
a, operation button P for setting and resetting each operation
Bb, an indicator IND for warning that a set time has elapsed or occurrence of an abnormal situation, and an electronic buzzer 29 are provided. A gas inlet F1 connected to the pressure reducer G is provided on the left side of the flow meter FM, and a gas outlet F2 connected to the tube 9 is provided on the left side of the flow meter FM. .

FIG. 4 is a system configuration diagram of the flow meter FM according to the first embodiment. As a function of the present flow meter FM, an excessive change in the flow rate within a single time input from a known hot-wire type flow sensor (abbreviated as a gas flow sensor) 1 disposed in a gas flow path F in the flow meter FM is described. A first function of determining a patient's respiratory abnormality and issuing an alarm to activate a shut-off valve V disposed in the middle of the gas flow path F, and a gas flow rate input from the gas flow rate sensor 1 decreases for a certain time or more. It has a second function of judging a flow rate abnormality at the time of judgment and issuing an alarm, and a third function of programmably setting the oxygen intake time, notifying that the set time has elapsed after the start of oxygen intake, and operating the shutoff valve V. .

The first function is constituted by sensor signal input means 3 which amplifies the sensor signal input from gas flow rate sensor 1 after temperature compensation, amplifies it, converts it to voltage, and outputs it. Of the sensor signal, the component whose level fluctuates repeatedly is shaped and pulse width modulated,
A signal waveform shaping unit 5 for converting into a pulse signal, a signal counting unit 7 for counting the number of pulses per fixed time, a respiratory abnormality is determined from the pulse counting result, and an alarm 29 is activated.
It is constituted by respiratory abnormality judging means 9 for activating the control unit 31 and operating the shut-off valve V as required.

As a second function configuration, the level of the sensor signal output from the sensor signal input means 3 is compared with a predetermined reference value, and it is determined whether or not the level has dropped below this reference value. Flow rate decrease determining means 11; decreasing elapsed time measuring means 13 for measuring whether a decreasing period has passed a preset time; and activating alarm means 29 when time elapse is recognized and flow rate abnormality is determined. The flow rate abnormality determination means 15 activates the control unit 31 and activates the shut-off valve V as necessary.

As a configuration of the third function, each clock pulse for setting the counting time unit to 1 second, 10 seconds, 1 minute, 10 minutes and 1 hour is generated by dividing the reference clock CK. Frequency dividing means 17, clock selecting means 19 for selecting a clock pulse to be used from a plurality of frequency-divided clock pulses, clock setting means 21 for setting a selected clock pulse, and counting value setting means 25 for selecting the selected clock pulse. The counting means 23 counts up to the preset numerical value (time), and the display unit 27 displays the numerical value (time) to be counted. The counting means 23 starts a counting operation toward a preset numerical value (time) together with the input of the sensor signal. When the preset time is reached, the counting means 23 activates the alarm means 29 and activates the control section 31 to turn off the shut-off valve V. Activate.

Next, the operation of each function will be described with reference to the circuit diagrams of FIGS. First, the first function will be described. As shown in FIG. 5, the comparator COM1 constituting the signal waveform shaping means 5 inputs a sensor signal from the sensor signal input means 3 to a negative terminal and a reference voltage Vref to a positive terminal.
Enter Normally, if the patient is inhaling oxygen in a normal state, a substantially constant amount of oxygen flows through the gas flow path F, so that the gas flow sensor 1 sends a sensor signal having a stable level to the sensor signal input means 3. Is entered.

As a result, an L level signal is output from the comparator COM1 to one input terminal of the AND gate AD1. Therefore, no matter what logical level signal is input to the other input terminal of the AND gate AD1, the output of the AND gate AD1 maintains the L level. Therefore, AN
The programmable counter (signal counting means 7) PC1 which inputs the output of the D gate AD1 to the clock input terminal CK does not perform the counter operation.

However, if a patient suffers from respiratory abnormalities during oxygen inhalation, the flow voltage level changes up and down from the reference voltage Vref in accordance with respiratory disturbances. As a result, the output of the comparator COM1 changes to the H level every time the flow rate (converted voltage value) falls below the reference voltage Vref, is pulse width modulated, and is input to one input terminal of the AND gate AD1. The AND gate AD1 receives an H-level event pulse signal of 1-minute width T1 from the pulse generation circuit P1 at the 3-minute interval T2 at the other input terminal.
The pulse signal output from the comparator COM1 for a minute is used as a clock signal as a programmable counter PC.
1 clock input terminal CK.

Here, the programmable counter PC1 calculates the number of pulses per minute for determining respiratory abnormality,
Switch SW1 by pressing down time setting button PBa
Is set in a binary system by a combination of ON / OFF.
For example, if the number of count pulses per minute is five, the combination of ON / OFF of the switch SW1 is “1”.
"010" is preset to the input terminal of the programmable counter PC1.

The operation of the programmable counter PC1 which also constitutes the respiratory abnormality determining means 9 is as follows. When an H-level event pulse signal is output from the pulse generation circuit P1, the inverter IV1 inverts the output to an L level and outputs the programmable counter PC1. The clock pulses output from the AND gate AD1 and input to the clock terminal CK are counted toward the preset number of pulses in order to input them to the chip enable terminal CE.

When the count value reaches the preset value, an L-level signal is sent from the carry terminal CA to the alarm 29 and the controller 31.
Is output to the electronic buzzer (alarm device) 29, the indicator (alarm device) IND flashes, and the control unit 3
1 is started to operate the shut-off valve V.

Since the event pulse signal is inverted to the L level after one minute has elapsed, it is input to the clear terminal CL of the programmable counter PC1 through the inverter IV2, and the count value is initialized to a preset value. Here, if one minute elapses before the programmable counter PC1 does not count the preset number of clock pulses, the carry terminal CA does not change to the L level. Therefore, it is determined that the level fluctuation of the flow rate is caused by a transient noise component. When one minute has elapsed, the event pulse goes to the L level, and is input to the clear terminal of the programmable counter PC1 through the inverter IV2 to reset the count value to a preset value.

The pulse generation circuit P1 outputs an event pulse signal having a one-minute width at three-minute intervals.
2 and the pulse width T1 are not limited to these and can be varied. That is, as shown in the variable duty ratio type pulse generating circuit of FIG.
Determines the pulse width T1 by the time constant due to the value of the timing capacitor C ₁ of values and a variable resistor R ₄₀ by varying the _40, also of the timing capacitor C ₁ of the variable resistor R ₅₀ for discharge time setting by varying pulse output interval T2 is determined by the time constant due to values of the variable resistor R _50.

In this circuit, the timing capacitor
C₁The charging time of the variable resistor R₄₀And diode D_TwoAnd flow
Variable resistor R₄₀Change the resistance value of the
Densa_C1Together with the charging time constant determines the pulse width T1
Round. The discharge current of the timing capacitor C1 is
Anti-R₅₀And diode D_TwoVariable resistor R_{Five 0}of
If the resistance value changes, the pulse output interval T2 changes.

[0032] Therefore, it is possible to change independently the pulse width T1 and the pulse output interval T2 by changing the value of the variable resistor R ₄₀ and R ₅₀ independently. Note that the pulse width T1 and the pulse interval T2 can be derived from the following equations.

T1 = −R ₄₀ · C ₁ ln (1/2) ≒ 0.
_{694R 40 · C 1 T2 = -R} 50 · C 1 ln (1/2) ≒ 0.694R 50 ·
C ₁

By using this first function, even if the oxygen flow rate fluctuates between high and low due to abnormal respiratory action of the patient, the abnormality is immediately detected, an alarm is issued, and the oxygen inhalation is automatically stopped. it can.

Next, the second function will be described. As shown in FIG. 7, the comparator COM2 constituting the flow rate decrease judging means 11 constitutes a Schmitt circuit together with the resistors R1, R2 and R3, and the sensor signal temporarily reduces the reference voltage EL and the output is inverted to the H level. After that, even if the reference voltage EL slightly exceeds the reference voltage EL due to the noise component mixed with the sensor signal, the reference voltage EL does not invert to the L level because the reference voltage EL increases by the amount of the systemic. Therefore, the comparator COM
Hunting of output 2 can be prevented.

When the flow level decreases, the comparator CO
The H-level signal output from M2 is connected to inverter IV
4, the signal is inverted to an L level signal and input to the chip enable terminal CE of the programmable counter PC2. The programmable counter PC2, which constitutes the decrease elapsed time measuring means 13 and the flow rate abnormality judging means 15, inputs a clock signal of 10 seconds from a frequency dividing circuit to be described later, and turns ON / OFF of SW1 by operating the time setting button PBa to the input terminal. A pulse count value, for example, a value equivalent to 2 minutes is preset by a binary number in a combination of OFF.

In the state where the flow rate is decreasing, the programmable counter PC2 counts clock pulses toward a preset value. When the counted value reaches the preset value, the carry terminal CA outputs an L-level signal to the electronic buzzer 29 and the indicator IND29, which are alarms, and the control unit 3
At the same time, the electronic buzzer 29 is sounded, the indicator IND is flashed, the control unit 31 is activated, and the shutoff valve V is operated.

When a normal flow rate of oxygen is being inhaled by the patient, the output of the comparator COM2 is at the L level, and therefore, the inverter IV is connected to the chip enable terminal CE.
The counter operation is not performed because the H level signal inverted at 4 is input. Further, when the flow rate abnormality is transient and returns from the abnormality to the normal state before the counting operation is completed, the output of the comparator COM2 is inverted from the H level to the L level. Therefore, the inverter IV3 is connected to the clear terminal CL.
A higher level signal is input, the preset initial state is entered, and the chip enable terminal CE receives the H level signal inverted by the inverter IV4, so that the counter operation is not performed.

By using the above second function,
Since it is possible to determine that the oxygen inhalation has been stopped for a certain period of time by eliminating the influence of the noise of the sensor signal, the monitoring accuracy is improved, and the trouble of the person in charge due to the erroneous determination of the oxygen inhalation stop can be reduced. Furthermore, if the temporary abnormality is resolved before the end of the counting operation, the programmable counter PC2 automatically returns to the initial preset state and shifts to the flow rate abnormality judging operation.

Next, the third function will be described. First,
In this function, in order to count the oxygen inhalation time by the number of pulses, the frequency dividing circuit (FIG. 8) constituting the frequency dividing means 17 sequentially divides the one-second reference clock to 10 seconds clock and one minute clock. , A 10-minute clock and a one-hour clock are generated and input to the multiplexer MUL constituting the clock selecting means 19.

In the multiplexer MUL, when it is desired to operate the shut-off valve V, for example, 90 minutes after inhaling oxygen, the switch SW3 constituting the clock setting means 21 is required.
ON / OFF (by operating the time setting button PBa)
, The output of the one-minute clock is set, and the multiplexer MUL selectively outputs the one-minute clock to the counting means 23.

The counting means 23 has a program counter P for counting 1 digit and 10 digits as shown in FIG.
C3 and PC4 and display unit driving drivers D1 and D2 for displaying the count values of the program counters PC3 and PC4 on the display unit 27 are provided. Each program counter P
C3 and PC4 employ a down-counting method and are cascaded to connect the carry terminal C of the preceding program counter PC3 and the clock terminal CK of the succeeding program counter PC4.

Each of the program counters PC3 and PC4 is
The pulse count value is preset by a binary number in a combination of ON / OFF of SW4 and SW5 (count value setting means) by operating the time setting button PBa. In the counting operation, when a sensor signal is input to the set terminal S of the R / S flip-flop F, an H level signal is held and input to the chip enable terminal CE from the Q terminal.

Hereinafter, the counting operation will be described in detail. For example, when setting the oxygen inhalation time to 90 minutes,
By operating the switch SW4, the program counter PC3
Is set to “0” and the digit of 1 is set to “0”. Next, the preset value of the program counter PC3 is set to “9” by operating the switch SW5, and 1
The digit of 0 is “9”. When the preset is completed and the sensor signal is input to the set terminal of the R / S flip-flop, “0” is displayed on the 1-digit display section, and “9” is displayed on the 10-digit display section. .

At this time, since the one-minute clock is input from the multiplexer MUL to the clock terminal CK of the program counter PC3, when a sensor signal is input, 1 is subtracted from "90" every one minute, and the display unit Are changed to 89, 87, 88, 86,... Finally, when the subtraction value becomes "0", an L-level signal is output from the carry terminal CA of the program counter PC3 to the alarm 29 and the control unit 31 through the OR gate OR, and the shutoff valve V is activated to stop oxygen intake. I do.

To reset the count value and start counting again regardless of the input of the sensor signal, the operation button PB
By pressing the reset button PB2 in b, the reset terminal R of the R / S flip-flop F is set to L level and the chip enable terminal CE is set to L level, thereby initializing the program counters PC3 and PC4 to "0" and "9". And

Thereafter, the set button PB1 is pressed to
By setting the set terminal S of the / S flip-flop F to the H level and the chip enable terminal CE to the H level, the program counters PC3 and PC4 start counting toward "0" every time a clock signal is input. I do.

As described above, the use of the third function facilitates the setting of the oxygen inhalation time, and automatically stops the oxygen inhalation after the set time has elapsed. Eliminates the need to attend.

In each function, the setting values of the program counters PC1 to PC3 and the multiplexer MUL are described in each drawing so as to be performed by operating the individual switches SW1 to SW5. However, in actuality, as shown in FIG. 10, when the time setting button PBa shown in FIG. 3 is used to set, for example, the oxygen inhalation time to 90 minutes and the clock pulse at that time to 1 minute clock, first, the quinary The set button PB3 connected to the clock input of the ring counter RC is repeatedly turned ON / OFF four times, and four clock pulses are manually input to the quinary ring counter RC for counting.

As a result, the fourth output of the quinary ring counter RC becomes H level, and is input to the strobe terminal of the tristate buffer TB corresponding to the switch SW4, so that it becomes conductive. Next, when "0" of the time setting button PBa is depressed, the switch S0 is turned ON and the decimal BCD
A binary signal “0000” corresponding to “0” is input from the BCD output terminal of the encoder to the set terminal S of the corresponding R / S flip-flop F / F through the conductive tri-state buffer TB. As a result, "0000" is latched at the output terminal Q of the R / S flip-flop F / F, and the programmable counter PC3 that counts one digit is preset, and "0" is displayed on the display unit of the one digit.

Next, the set button PB3 is depressed once more, and the number is counted by the quinary ring counter RC.
The fifth output of the quinary ring counter RC becomes the H level, and the tristate buffer T corresponding to the switch SW5 is set.
The signal is input to the B strobe terminal and becomes conductive. Next, when "9" of the time setting button PBa is pressed, the switch S
9 turns ON, and a binary signal “1001” corresponding to “9” is output from the BCD output terminal of the decimal BCD encoder through the conductive tri-state buffer TB.
/ S flip-flop F / F is input to the set terminal S. As a result, "1001" is latched at the output terminal Q of the R / S flip-flop F / F, and is preset in the programmable counter PC4 for counting the tenth digit.
9 is displayed on the display section of the digit.

Similarly, the output of the multiplexer MUL is selected by the output of the quinary ring counter in FIG.
After turning on the tri-state buffer TB corresponding to the switch SW3 shown in FIG.
A binary signal "1100" corresponding to "3" is input from the BCD output terminal of the binary BCD encoder to the set terminal S of the corresponding R / S flip-flop F / F through the conductive tristate buffer TB.

Output terminal Q of each S flip-flop F / F
Is latched by the multiplexer MU as a selection signal for selecting a one-minute clock.
L signal selection terminal. Multiplexer MUL
Inputs a one-minute clock to the clock terminal CK of the programmable counter PC3 shown in FIG. 9 according to the selection signal.

The R / S flip-flop circuit F / F constituting the latch circuit corresponding to each of the switches SW1 to SW5 performs a reset operation in response to an external reset signal. The quinary ring counter RC also performs a reset operation by the reset signal. Each programmable counter PC1,
The output of the PC2 and the output of the ring counter RC can be switched to the driver D1 or D2 for monitoring. Further, the control unit 31 may be activated after a predetermined time has elapsed after the operation of the alarm 29. Although the present embodiment is implemented in hardware, it can also be implemented by software using a microcomputer.

As described above, according to the present invention, a plurality of types of counting operations can be performed using a signal from a single clock source, and a single time setting and signal selecting operation can be performed simultaneously in each counting operation. This can be performed by signal setting means.

[0056]

According to the present invention, a medical device is connected to a tube connected to an inhalation mask mounted on a patient and measures the flow rate of medical gas supplied to the patient from a gas supply source in an internal gas flow path. A flow sensor for measuring the flow rate of the medical gas that is disposed in the gas flow path and passes through the gas flow path from the gas supply source toward the mask, and A sensor signal input means for processing the input sensor output into a predetermined electrical signal and outputting the same, and a supply time measuring means for measuring a supply time of the medical gas to the patient with the signal output from the sensor signal input means. A supply judging unit for judging the end of the supply based on a gas supply judgment for a certain period of time; If medical gas is supplied to the patient for a preset time, the control means is activated and the gas supply shut-off valve is operated to automatically shut off, so that a medical staff member is always placed around the patient. There is no need to do this, and there is an effect that the number of people can be reduced.

According to the present invention, the respiratory frequency of the patient at the time of gas inhalation is measured by the respiratory frequency measuring means, and the respiratory abnormality determining means determines that the respiratory frequency per unit time is equal to or greater than the set number. Then, by issuing a warning by the warning means, it is possible to immediately detect a sudden change in the patient's condition during gas inhalation.

According to the present invention, the decrease in the gas flow rate is measured by the flow rate decrease measuring means based on the signal level output from the sensor signal input means, and the decrease in the gas flow rate is continuously recognized for a preset time. At this time, there is an effect that the interruption of the supply of the medical gas can be detected at an early stage by determining the flow rate abnormality by the flow rate abnormality determining means and activating the alarm means.

According to the present invention, when an abnormality is determined for a short time within the measurement time of the number of breaths or the measurement time of the decrease in the flow rate due to mixing of a noise component into the sensor signal, the abnormality is determined to be transient. By not operating the alarm means, it is possible to prevent an erroneous determination of an abnormality due to noise.

According to the present invention, even if an abnormality is determined for a short time within the measurement time of the number of breaths or the measurement time of the decrease in the flow rate due to mixing of noise components into the sensor signal, the abnormality is determined to be transient. Without operating the alarm means, returning the breathing frequency measurement time or flow rate reduction measurement time to the initial state,
By performing the timing operation again, it is possible to monitor the respiratory abnormality or the flow rate abnormality without being affected by the occurrence of the past abnormality, so that there is an effect that the abnormality monitoring accuracy is improved.

According to the present invention, the determination of the respiratory abnormality and the determination of the abnormal flow rate are performed simultaneously with the measurement of the supply time of the medical gas, so that the monitoring of the condition of the patient during the gas supply and the safety management of the gas supply equipment can be performed at the same time. In addition, since it can be performed using the same equipment, an extremely multifunctional medical gas flowmeter can be provided.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a medical gas flow meter according to the present invention.

FIG. 2 is an explanatory diagram showing a use state of the medical gas flow meter according to the present invention.

FIG. 3 is a front view of the medical gas flow meter according to the present embodiment.

FIG. 4 is a system configuration diagram of a medical gas flow meter according to the present embodiment.

FIG. 5 is a diagram showing a specific circuit of a signal waveform shaping unit, a signal counting unit, and a respiratory abnormality determining unit shown in FIG. 4;

FIG. 6 is a diagram showing a specific circuit of the pulse generation circuit shown in FIG. 5;

FIG. 7 is a specific circuit diagram of a flow rate decrease determination unit, a decrease elapsed time determination unit, and a flow rate abnormality determination unit shown in FIG. 4;

FIG. 8 is a diagram showing a specific circuit of a frequency divider and a clock selector shown in FIG. 4;

FIG. 9 is a diagram showing a specific circuit of a counting unit, a counting setting unit, and a display unit shown in FIG. 4;

FIG. 10 is a diagram showing a circuit for setting a count value of each programmable counter PC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow rate sensor F Gas flow path M Mask T tube FM Medical gas flow meter 3a Sensor signal input means 5a Respiration frequency measurement means 5b Respiratory abnormality determination means 15a Flow rate decrease measurement means 15b Flow rate abnormality determination means 23a Supply time measurement means 23b Supply end Determination means 29a alarm means 31a control means 33 gas supply source

Claims (6)

[Claims] 1. A medical gas flow meter connected to a tube connected to an inhalation mask mounted on a patient and measuring a flow rate of a medical gas supplied from a gas supply source to the patient in an internal gas flow path. A flow sensor for measuring a flow rate of the medical gas passing through the gas flow source from the gas supply source toward the mask, and a sensor output input from the flow sensor. A sensor signal input unit that processes and outputs a predetermined electric signal, and a supply time measurement unit that measures a supply time of the medical gas to the patient with a signal output from the sensor signal input unit,
A medical device comprising: supply determining means for determining the end of supply based on determination of gas supply for a predetermined time; and control means for operating a gas supply cutoff valve based on a determination result by the supply determining means. Gas flow meter. 2. A respiratory rate measuring means for measuring a respiratory rate of a patient wearing the inhalation mask on the basis of a number of level changes per unit time of a signal output from the sensor signal input means; 2. The medical gas according to claim 1, further comprising: a respiratory abnormality determining means for determining a respiratory abnormality when the number of respirations is equal to or greater than a set number of times, and an alarming means for issuing an alarm based on the respiratory abnormality determination result. Flowmeter. 3. A flow rate decrease measuring means for measuring a decrease in gas flow rate from a level of a signal output from the sensor signal input means, and a flow rate abnormality is determined when a flow rate decrease is recognized for a preset time. 2. The medical gas flow meter according to claim 1, further comprising a flow rate abnormality determining unit that activates an alarm unit. 4. The medical gas flow meter according to claim 2, wherein each of the abnormality determination units determines a transient abnormality and makes an operation signal to an alarm unit insignificant. 5. The apparatus according to claim 2, wherein each of the abnormality judging means judges a transient abnormality, makes the operation signal to the alarm means insignificant, and returns the judging operation to the initial operation. Medical gas flow meter. 6. Simultaneously with the supply time measurement of the medical gas,
The medical gas flowmeter according to any one of claims 1 to 5, wherein the respiratory abnormality determination and the flow rate abnormality determination are performed.