JPH06121770A - Gas ventilating device - Google Patents

Abstract

PURPOSE:To provide a gas ventilating device by which accurate pressure can be measured even if a flow rate is changed and control to hold the peritoneal cavity inside under prescribed pressure becomes possible. CONSTITUTION:A pressure sensor 16 and a flow rate measuring means 14 are arranged in a gas ventilating device 10 to supply gas into the peritoneal cavity through a pipe shape ventilator 3 to be stuck in the human body or the abdominal region of an animal, and a pressure operation means 30 is arranged to find a pipe conduit resistance factor of a gas line from a pressure value and a flow rate value obtained by these pressure sensor 16 and flow rate measuring means 14 as well as to calculate a pressure value in the peritoneal cavity according to this pipe conduit resistance factor. Since the pressure value in the peritoneal cavity is calculated according to the pipe conduit resistance factor, even if a gas flow rate is changed, pressure in the peritoneal cavity can be found accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas venting device for supplying a gas such as carbon dioxide (CO2) gas into the abdominal cavity of a human body or an animal, and the internal abdomen of the human body or the animal is operated or examined by an endoscope. Available at the time.

[0002]

BACKGROUND ART In recent years, a surgical operation has been performed in which forceps, an electric scalpel or the like that can be operated outside the body are inserted into a pipe-shaped instrument punctured in the abdomen, and the operation is performed while looking inside the abdominal cavity with an endoscope. Since such an operation does not make a large incision in the abdomen,
Wounds due to surgery are extremely small, and there are advantages such as quick recovery after surgery.

In performing such an operation, gas such as CO 2 gas is supplied into the abdominal cavity to inflate the abdomen. For supplying this gas, a gas venting device that adjusts the pressure, flow rate, etc. to a predetermined value is used.

As such a gas ventilation device, a pressure detecting means such as a pressure sensor is provided in the middle of a gas line for guiding gas into the abdominal cavity, and a resistance pressure value of the gas line which is obtained in advance is detected during gas supply. There is a device for calculating the static pressure value in the abdominal cavity based on the calculated pressure value, for example, a device disclosed in Japanese Patent Publication No. 2-14843.

When supplying gas into the abdominal cavity with such a device, pressure is detected by the pressure detecting means at the start of the supply after the turbulence of the pressure has subsided and before the abdominal cavity is pressurized. Thus, the resistance pressure value of the gas line is detected, and the gas pressure in the abdominal cavity is obtained based on this resistance pressure value.

[0006]

In the gas venting apparatus as described above, the flow rate of the gas supplied to the abdominal cavity may be changed during normal examination or surgery. Since the resistance pressure changes and control cannot be performed with the detected resistance pressure value, it becomes necessary to correct the resistance pressure value. However, to correct the resistance pressure value, there is no choice but to measure the resistance pressure value of the gas line,
Since the measurement of the resistance pressure value is limited at the time of starting the gas supply, the resistance pressure value cannot be corrected until the operation or the like is completed and all the gas in the abdominal cavity is exhausted. Therefore, when the flow rate is changed, accurate pressure measurement cannot be performed, and there is a problem in that it is not possible to control the inside of the abdominal cavity at a predetermined pressure.

An object of the present invention is to provide a gas venting device which enables accurate pressure measurement even when the flow rate is changed, and which enables control to maintain a predetermined pressure in the abdominal cavity.

[0008]

According to the present invention, there is provided a gas line for supplying gas into the abdominal cavity of the human body or animal through a pipe-shaped ventilator punctured in the abdomen, and the flow rate of the gas flowing in the gas line. A gas ventilation device comprising: a flow rate measuring means for measuring; a flow rate adjusting valve for adjusting a gas flow rate in the gas line; and a pressure sensor for detecting a pressure on a downstream side of the flow rate adjusting valve of the gas line. A pressure calculating means for calculating a pressure value in the abdominal cavity based on a pressure resistance value detected by the pressure sensor and a flow path resistance coefficient of a gas line obtained from a flow rate value detected by the flow rate measuring means. Characterize.

Here, as the pressure calculating means, a stop pressure value holding portion for holding the stop pressure value obtained by the pressure sensor when the gas supply is stopped, and a supply obtained by the pressure sensor when the gas is supplied. The supply pressure value holding section that holds the hour pressure value, the flow rate value holding section that holds the flow rate value obtained by the flow rate measuring means at the time of supply, and the respective values held by the respective holding sections are input to stop the operation. It is preferable to employ one having a coefficient calculation unit that calculates a quotient obtained by dividing the difference between the pressure value and the supply pressure value by the square of the flow rate value as a pipeline resistance coefficient.

[0010]

In the present invention as described above, the pressure coefficient in the gas line is calculated by the calculation of the pressure calculating means, and the pressure value in the abdominal cavity is calculated based on this resistance coefficient of the gas line, so that the flow rate of the gas is changed. Even then, the pressure in the abdominal cavity can be accurately determined.

That is, the pressure P _S in the abdominal cavity is obtained by subtracting the resistance pressure dP of the gas line generated by the flow of gas from the pressure P applied to the pressure sensor. here,
Since the resistance pressure dP is proportional to the square of the flow rate Q of gas flowing through the gas line, the pressure P _S in the abdominal cavity can be calculated by the following equation.

## EQU1 ## P _S = P-ζQ ² (1) where ζ is a conduit resistance coefficient. Therefore, if the pipeline resistance coefficient ζ is obtained, even if the pressure P or the flow rate Q changes or is changed to any value, if it is detected by the pressure sensor and the flow rate measuring means and calculated by the pressure calculating means, The pressure P _S can be calculated accurately.

Further, the conduit resistance coefficient ζ can be easily calculated by the following configuration, for example. That is,
As a pressure calculation means, a first holding unit that holds the first pressure value P _A obtained by the pressure sensor when the gas supply is stopped,
A second holding unit that holds the second pressure value P _B and the flow rate value Q _B obtained by the pressure sensor and the flow rate measuring unit when gas is supplied, and the pipeline resistance coefficient ζ based on these values. And a coefficient calculator.

[0013] According to such pressure calculation means,
If the supply is not very high, supply gas intermittently.
Pressure in the abdominal cavity P_SSupply does not change rapidly
After that, if the pressure within the specified time is equal to the pressure before the start of supply,
Can be viewed For this reason, the stop measured when the gas supply was stopped
Hour pressure value P_AAnd within a predetermined time from the start of gas supply.
Fixed supply pressure value P_BAnd flow rate value Q_BAnd
From equation (1), the following relationship holds. P_A= P_B-ΖQ_B ² When this equation is transformed,

## EQU2 ## ζ = (P _B −P _A ) / Q _B ² (2) is derived.

Therefore, the pressure value P _A at the time of stoppage is held, the pressure value P _B at the time of supply and the flow rate value Q are held, and the coefficient calculation unit (2) based on these values P _A, P _{B and} Q _B. ), The pipe resistance coefficient ζ can be easily calculated, and the above object is achieved by these.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a gas ventilation device 10 according to this embodiment. The gas ventilation device 10 is a cylinder 1 that is a gas supply source.
The gas inside is supplied to the abdominal cavity 2. In the abdominal cavity 2,
The ventilator 3 which is a pipe needle is punctured, and the ventilator 3
The gas from the cylinder 1 is supplied via the.

The gas ventilation device 10 includes a gas line 1A for connecting the cylinder 1 and the abdominal cavity 2, a control device provided in the middle of the gas line 1A, and a control circuit 20 for controlling these control devices. have. Pressure gauge as control equipment 1
1, pressure reducing valve 12, solenoid valve 13, flow rate sensor 14, flow rate adjusting valve 1
5, a pressure sensor 16 is provided, which are sequentially installed from the upstream side of the gas line 1A.

The pressure gauge 11 displays the pressure of the gas discharged from the cylinder 1. The pressure reducing valve 12 reduces the pressure of the high pressure gas sent from the cylinder 1 to a predetermined pressure.

The solenoid valve 13 is opened / closed by a control signal of the control circuit 20, and the abdominal cavity 2 is opened / closed by the opening / closing operation of the solenoid valve 13.
The pressure of is adjusted.

Each of the flow rate sensor 14 and the flow rate adjusting valve 15 is a device for adjusting the flow rate of gas to a predetermined amount. The flow rate sensor 14 measures the flow rate of the gas flowing through the gas line 1A, and a control circuit outputs a predetermined signal corresponding to the flow rate.
It is designed to output to 20. The flow rate adjusting valve 15 performs an opening / closing operation according to a control signal of the control circuit 20 in order to adjust the flow rate of the gas flowing in the gas line 1A.

The pressure sensor 16 detects the pressure of the gas in the gas line 1A, and outputs a signal corresponding to the detected pressure value to the control circuit 20.

The control circuit 20 is composed of a microcomputer or the like. The control circuit 20 includes a control unit 21 for controlling the solenoid valve 13, the flow control valve 15, etc., a display unit 22 for displaying a pressure value etc. in the abdominal cavity 2, and a pressure value P _S in the abdominal cavity 2.
And a calculation unit 30 which is a pressure calculation unit for calculating

The calculation unit 30 uses the pressure value P from the pressure sensor 16.
And the pressure value P based on the flow rate value Q from the flow rate sensor 14.
_It calculates _S. The calculation unit 30 includes a first and second holding unit 3 for holding a pressure value obtained at a predetermined timing.
1, 32, a coefficient calculation unit 33 for calculating the pipeline resistance coefficient ζ,
A pressure calculation unit 34 for calculating the pressure value P _S based on the numerical values such as the pipe resistance coefficient ζ is provided.

The first holding portion 31 holds the pressure at stoppage P that is the pressure value at stoppage P _A detected by the pressure sensor 16 when the gas supply is stopped, that is, immediately before the solenoid valve 13 is opened. It is a value holding unit. The second holding unit 32, when supplying gas,
That is, after the opening of the solenoid valve 13, together with the flow rate is supplied at a pressure holding portion for holding the pressure value P _B is a pressure value when supply detected by the pressure sensor 16 at a stable point, the pressure value P _B
Flow rate value Q _B detected by flow rate sensor 14 almost at the same time
It also serves as a flow rate holding unit for holding the.

[0024] The coefficient calculation unit 33 determines the pressure value P of the first holding unit 31.
_A, The pressure value P of the second holding portion 32_BAnd flow rate value Q_BBased on
The pipeline resistance coefficient ζ is calculated. In particular,
The above value P_A,P_B,Q_BFrom (P_B-P_A) / Q_B ²To
It is configured to perform a calculation to calculate the pipeline resistance coefficient ζ.
It

The pressure calculation unit 34 calculates the pressure value P _S in the abdominal cavity 2 based on the duct resistance coefficient ζ obtained by the coefficient calculation unit 33. Specifically, from the pressure value P and the flow rate value Q obtained by the pressure sensor 16 and the flow rate sensor 14, respectively, P-ζQ
It is configured to calculate ² to calculate the pressure value P _S in the abdominal cavity 2. As a result, unless the conduit resistance coefficient ζ is changed by adding or changing the ventilator 3 and the gas line 1A, the pressure value P and the flow rate value Q
Even if is greatly changed / changed, the pressure value P _S is accurately calculated.

The pressure calculation unit 34 is used to open and close the solenoid valve 13.
The control operation is disturbed due to the pressure disturbance that occurs immediately after the operation.
Flow from the opening of the solenoid valve 13 to prevent
Until the pressure stabilizes, the pressure value P detected immediately before opening_S0
And hold this value P_S0Is output to the control unit 21.
It is like this. On the other hand, a predetermined time after the solenoid valve 13 was closed
T₂Is the pressure value detected immediately before closing until
P_S1And hold this value P_S1Is output to the control unit 21.
It is supposed to do.

Next, refer to FIG. 2 for the operation of this embodiment.
I will explain. First, to operate the gas ventilation device 10,
Or the abdomen of the human body or animal to be operated on beforehand.
Puncture the air vessel 3 and turn on the gas ventilation device 10.
To start gas supply. The pressure of the pressure sensor 16 is
Pressure value P_FourSolenoid valve 13 is closed when
Control the rise of power. In addition, the pressure of the pressure sensor 16 is a predetermined pressure.
Force value P_FourSurgery can be started by reaching
it can.

The supply of gas is stopped by closing the solenoid valve 13.
Then, the pressure inside the abdominal cavity 2 begins to drop and
The pressure value P_SIs directly detected by the pressure sensor 16. That
Then, at time t in FIG.₁Then, the pressure value P in the abdominal cavity 2 becomes_SBut
P_S0Falls to. At this point the pressure value P_S0The pressure sensor
After detecting with 16 and inputting to the 1st holding part 31, open the solenoid valve 13.
Release the gas to suppress the pressure decrease. Where time
Tick t₁From time t₂Time to₁The flow rate of the gas during
Is the flow rate value Q _1,Q₂Between the pressure sensor 16 and
Pressure is pressure value P_1,P₂Disturbed greatly between. This turbulence
Becomes a control disturbance, so time t₁~ T₂Control during
Pressure value P on part 21_S0Enter.

[0029] Time t₂Is a predetermined flow rate Q of gas_E
Since the gas supply is performed at a constant flow rate at time t,
₂At that time, pressure sensor 16 and flow sensor 14
Informed pressure value P₃And flow rate value Q_EThe second holding part 32
The pressure value P output from the first holding unit 31 via_S0With
Is input to the coefficient calculation unit 33. These values P_S0,P_3,Q
_EThe pipe resistance coefficient ζ is calculated based on

After time t ₂ , the calculated pipeline resistance coefficient ζ
Since the pressure value P _S in the abdominal cavity 2 can be accurately obtained by the pressure calculation unit 34 based on the above, the control unit 21 controls the pressure in the abdominal cavity 2 based on the calculated pressure value P _S. Become.

The pressure of the pressure sensor 16 rises due to the opening of the solenoid valve 13, and reaches the pressure value P ₄ at time t ₃ . At this point, the solenoid valve 13 is closed to suppress the pressure rise. Here, the predetermined time T ₂ of the to time t ₄ from time t _3, the flow rate and pressure decreases rapidly, since the rapid change causes disturbing control, between times t ₃ ~t ₄ Inputs the pressure value P _S1 obtained immediately before the solenoid valve 13 is closed to the control unit 21. After time t ₄ , the gas ventilation device is repeatedly operated while repeating operations such as calculation of the pipeline resistance coefficient ζ each time the solenoid valve 13 is opened and closed.
Ten pressure control operations continue.

According to this embodiment as described above, the following effects can be obtained. That is, the operating unit 30 is provided with the holding units 31 and 32, and these holding units 31 and 32 are provided before the solenoid valve 13 is opened. Since the pressure value P _S0, the pressure value P ₃ after opening, and the flow rate value Q _E can be held, the conduit resistance coefficient ζ can be obtained from these held values P _S0, P _3, Q _E. By calculating based on this conduit resistance coefficient ζ, the pressure value P _S in the abdominal cavity 2 can always be accurately calculated even if the flow rate value changes / changes, and the abdominal cavity 2 is kept at a predetermined pressure. You can control to hold it accurately.

Further, since the pipeline resistance coefficient ζ is recalculated each time the solenoid valve 13 is opened, even if the pipeline resistance changes, the solenoid valve 13 operates immediately after the change. Accordingly, since the conduit resistance coefficient ζ is newly calculated, the control based on the inaccurate calculation value calculated by the coefficient ζ before the change is not continued, and from this point as well, the abdominal cavity 2 is pressurized to the predetermined pressure. It can be controlled to hold accurately.

Further, from the time when the solenoid valve 13 is opened until the flow rate is stabilized, the pressure value P _S0 detected and held immediately before the opening is adopted, and during the time period T ₂ after the closing time,
Since the pressure value P ₃ detected and held immediately before the closing is adopted, even if the flow rate value or the pressure value of the gas is disturbed by the opening / closing operation of the solenoid valve 13, the pressure control is not affected and is stable. Pressure control can be realized.

The present invention is not limited to the above-mentioned embodiment.
Not something that includes deformations such as the following
Is. That is, as the pressure measurement method, the solenoid valve 13
Open and close to stop the gas supply, and the pressure value P when the supply is stopped
_AAnd pressure value P during supply_BAnd flow rate Q_BAsk for
Their value P_A,P_B,Q_BCalculate the pipe resistance coefficient ζ based on
However, the opening of the flow rate adjusting valve 15 is changed.
By changing the flow rate without stopping the gas supply,
Different flow rate value Q_a,Q_bPressure value P at_a,P_bDetect
And the following formula,  ζ = (P_a-P_b) / (Q_a ²-Q_b ²) May be used to calculate the pipeline resistance coefficient ζ.

As a method of eliminating the influence of the opening / closing operation of the solenoid valve 13, the pressure value immediately before the opening / closing operation is detected and held as in the above embodiment, and the control immediately after the opening / closing operation is performed with this pressure value. The control operation is not limited to the method of stabilizing the control operation by, for example, slowly opening / closing the flow rate adjusting valve 15 instead of the opening / closing operation of the solenoid valve 13 and gradually increasing or decreasing the gas flow rate to stabilize the control operation. It may be a method.

[0037]

As described above, according to the present invention, accurate pressure measurement can be performed even when the flow rate is changed, so that control can be performed to maintain the abdominal cavity at a predetermined pressure.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a graph for explaining the operation of the embodiment.

[Explanation of Codes] 1A Gas line 2 Peritoneal cavity 3 Ventilator 10 Gas ventilator 14 Flow rate sensor as flow rate measuring means 15 Flow rate adjusting valve 16 Pressure sensor 30 Calculating section as pressure calculating means 31 First as stop pressure value holding section 1 holding unit 32 2nd holding unit that doubles as a pressure value holding unit during supply and a flow rate holding unit 33 coefficient calculation unit

Claims (2)

[Claims] 1. A gas line for supplying gas into the abdominal cavity of the human body or animal through a pipe-shaped ventilator punctured in the abdomen, and a flow rate measuring means for measuring the flow rate of the gas flowing in the gas line, A gas ventilation device having a flow rate adjusting valve for adjusting the gas flow rate in the gas line, and a pressure sensor for detecting the pressure on the downstream side of the flow rate adjusting valve of the gas line, wherein the pressure detected by the pressure sensor A gas ventilation device, comprising: a pressure calculation means for calculating a pressure value in the abdominal cavity based on a gas resistance value of a gas line obtained from a value and a flow rate value detected by the flow rate measuring means. 2. The gas venting apparatus according to claim 1, wherein the pressure calculation means includes a stop-time pressure value holding section that holds a stop-time pressure value obtained by the pressure sensor when the gas supply is stopped, and A supply pressure value holding unit that holds the supply pressure value obtained by the pressure sensor during supply, a flow rate value holding unit that holds the flow rate value obtained by the flow rate measurement unit during supply, and a holding unit held by each of the holding units. And a coefficient calculation unit for calculating a quotient obtained by dividing the difference between the pressure value during stop and the pressure value during supply by the square of the flow rate value as a pipeline resistance coefficient. Gas venting device characterized by.