JPH0368854A - Anesthesia strength/concentration monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an anesthesia strength/concentration monitor, and more specifically, by providing a specific anesthesia sensing element and a temperature/humidity sensing element, temperature compensation and humidity compensation can be achieved. This invention relates to anesthesia strength/concentration monitors that measure and display anesthesia strength and concentration by appropriately carrying out anesthesia.

[Prior art] Traditionally, anesthesia has been performed using inhalation anesthesia during surgery, and anesthesia and breathing management during this surgery are electrically controlled. Knowing the exhaled breath concentration is the key to safely performing surgery. However, among the various gases, concentration measuring devices for anesthetic gases are not very popular.

Conventionally, as an anesthetic gas concentration measuring device, '! There are single-volume analyzers and infrared anesthetic gas concentration meters.

[Problems to be Solved by the Invention] However, conventionally used mass spectrometers are expensive, large, and complicated to operate. Furthermore, infrared anesthetic gas concentration meters require gas suction and exhaust, and failure to do so may cause contamination in the operating room. There was a problem.

[Means for Solving the Problems] Therefore, as a result of extensive studies in view of the problems of the conventional anesthesia concentration meters described above, the present inventors have devised a method for directly measuring the anesthesia concentration or strength without suctioning and exhausting the anesthesia gas. possible,
Moreover, the inventors have discovered an anesthesia strength/concentration monitor that has little influence on temperature and humidity and can easily compensate for temperature and humidity, and have arrived at the present invention.

That is, according to the present invention, the temperature and humidity sensing element is sensitive to temperature and humidity but not to anesthetic gas, and is formed by lining an electrode with a low hygroscopic substance; and an anesthesia sensing element which is sensitive to temperature and humidity and is formed by lining an electrode with a mixture of lecithin and a low hygroscopic substance; and an anesthesia sensor connected to the anesthesia sensor; an electric circuit that displays the anesthesia strength or concentration corresponding to the amount of change in the capacitance of the anesthetic gas, and the electrical circuit that displays the anesthesia strength or concentration corresponding to the amount of change in the capacitance of the anesthetic gas, and Anesthesia strength/concentration monitor is provided that can reduce errors in measurement and simplify the canceling means by canceling and calibrating the amount of electrical change.

In the present invention, the anesthesia sensing element that is sensitive to anesthetic gas and also sensitive to temperature and humidity has an electrode, preferably a comb-shaped electrode, containing lecithin and a substance having low hygroscopicity (or low water absorption), that is, paraffin. , polyethylene, polypropylene, silicone, polyester, polycarbonate, hydrochloric acid rubber, polystyrene, vinyl chloride, and polysulfone. Among these, a mixture of lecithin and polyethylene is particularly preferred because it has excellent sensitivity to anesthetic gas and has a small electrical response to temperature and humidity.

On the other hand, as a temperature and humidity sensing element that is sensitive to temperature and humidity but not to anesthetic gas, the electrode, preferably the comb-shaped electrode, is made of a material with low hygroscopicity (or low water absorption), such as paraffin, polyethylene polypropylene, silicone, etc. ,
Preferably, it is lined with at least one material selected from the group consisting of polyester, polycarbonate, hydrochloric acid rubber, polystyrene, vinyl chloride, and polysulfone, and among the above lining materials, polyethylene or anesthetic gas is more sensitive than the anesthesia-sensitive element. This is preferable because it hardly reacts to water and exhibits the same electrical response to temperature and humidity as the anesthesia-sensitive element described above.

[Function] Anesthetic gas is brought into contact with an anesthesia sensing element lined with a substance whose capacitance changes in response to the anesthetic gas, and a temperature and humidity sensing element that is sensitive to temperature and humidity but not to anesthetic gas. By canceling and calibrating the amount of electrical change in temperature and humidity of the anesthesia sensing element with the amount of electrical change in temperature and humidity of the temperature and humidity sensing element, the temperature and humidity of the anesthesia gas can be adjusted.
Measure and display the correct anesthesia strength or concentration that is not affected by humidity.

[Examples] The present invention will be described in more detail below with reference to illustrated embodiments, but the present invention is not limited to these embodiments.

FIG. 1 shows an example of the anesthesia-sensitive element of the present invention, and FIG. 2 shows an enlarged partial cross-sectional view taken along the line AA' in FIG.

In the figure, reference numeral 10 denotes an anesthesia sensing element consisting of a comb-shaped electrode, and a substrate 11 made of a non-conductive material is coated with Cr or Al.
It is constructed by disposing an electrode element 12 formed from a material such as the like, and coating the electrode element 12 with a substance 14 sensitive to anesthetic gas.

The substrate 11 may be any non-conductive material, and its type is not particularly limited, and examples thereof include a glass-epoxy board, a Bakelite board, and the like.

On the other hand, the temperature and humidity sensing element also has the same basic structure as the anesthesia sensing element described above, and is composed of comb-shaped electrodes. What is different from an anesthesia-sensitive element is that the S material coated on the comb-shaped electrode is sensitive to temperature and humidity, is not sensitive to anesthetic gas, or has a smaller amount of electrical change in response to anesthetic gas than an anesthesia-sensitive element. This characteristic is that it is extremely small and does not electrically affect the amount of anesthesia sensitivity of the anesthesia sensing element.

Anesthesia sensing element 10 and temperature/humidity sensing element 15 prepared as described below are installed together to form an anesthesia sensor.

As shown in FIG. 3, it is connected to an adapter 16 for integration into an anesthesia (breathing) circuit.

Next, the electric circuit shown in FIG. 4 incorporating the anesthesia sensor will be explained.

The linear IC20 contains two standard timer circuits, with two resistors
1.22 and capacitance 23
4, the pulse width of the regular repetitive pulse signal is made to depend on the capacitance of the anesthesia sensitive element 10.

After the output is integrated by an integrating circuit consisting of a resistor 26 and a capacitance 27, it is impedance-converted by an amplifier 28, 29, and simultaneously passes through a low-pass filter 30, 31. The output signal is further amplified by an amplifier 32, and from 33 onwards. It is digitized by a converter in the circuit, and then processed and displayed.

Hereinafter, specific implementation results of the present invention will be explained.

(Example 1) 0.4 g of soybean lecithin was dissolved with stirring in a beaker containing 40 g of an ethanol solution with a special reagent concentration of 99.5% or higher, and this was used as Solution A. Next, pellets (granules) of low density polyethylene 0. tg at a temperature of 90° in a flask containing 20 g of xylene solution with a reagent grade concentration of 99.5% or higher.
The mixture was maintained at temperature C and dissolved with stirring. This was used as liquid B, and liquid A and liquid B were mixed.

0.5 cc of the mixed solution was applied to a comb-shaped electrode, and the solvents ethanol and xylene were evaporated and dried to obtain an anesthesia-sensitive element.

Next, pellets o and Ig of low-density polyethylene are kept at a temperature of 90'C in a flask containing 50 g of a xylene solution with a reagent grade concentration of 99.5% or higher, dissolved while stirring, and dissolved in C solution. And so. 0.5 cc of Solution C was applied to the comb-shaped electrode, and the solvent xylene was evaporated to dryness to obtain a temperature-humidity sensitive element.

The comb-shaped electrode used was made of chromium-aluminum alloy.
Electrode elements with a width of about 10 pm, a thickness of about Lops, and a length of about 4.1 mm are made of 60 anodes and 61 cathodes (59 electrodes, 2 on the water bowl side).
It is arranged and constructed on a glass-epoxy substrate with a size of about 3 m+m×7 mm. This electrode has a temperature of 21℃
, in a constant temperature layer with a humidity of 9%, the electrical resistance is 1xio"Ω
(applied voltage 10V). The capacitance of this anesthesia-sensitive element consisting of a comb-shaped electrode increased by about 49 F after coating with lecithin and polyethylene. In addition, the capacitance of the temperature and humidity sensitive element increased by about 2.5 pF after coating with polyethylene.

Next, as shown in Figure 3, a pixel element is added to form an anesthesia sensor, and this anesthesia sensor is connected to the electric circuit shown in Figure 4.
The anesthesia sensitive element 10 and the temperature/humidity sensitive element 15 are respectively connected using the same. Here, the temperature/humidity sensing element 15 is connected to the connection part of the anesthesia sensing element 10 through the electric circuit shown in FIG. The two electric circuits shown in FIG. 4, that is, the electric circuit connected to the anesthesia sensing element and the electric circuit shown in FIG. 4 connected to the temperature/humidity sensing element, are This corresponds to an electric circuit section 50 including the anesthesia sensing element 40 and an electric circuit section 51 including the temperature/humidity sensing element 41 which are connected. That is, control, arithmetic processing, display, etc. are performed in the blocks after the A/D converters 42 and 43 of the electric circuit shown in FIG.

Next, the block diagram of FIG. 5 will be explained.

In the A/D conversion sections 42 and 43, the analog signals from the electric circuit section 50 including the anesthesia sensing element and the electric circuit section 51 including the temperature and humidity sensing element are converted into digital signals.
Digital conversion is performed and a digital signal is input to the I10 converter 44.

The I10 conversion section 44 and the CPU section 45 exchange data. Further, the CPU section 45 takes in a program for controlling and managing the operation of the entire circuit shown in FIG. , the measurement data and programs accumulated and stored in the RAM section 47 are sequentially fetched and the data are subjected to arithmetic processing.

The arithmetic-processed data is again passed through the I10 converter 44,
The signal is output toward the display section 49. During this time, the latch section 48 latches the display section 4.
9, static display is performed.

Therefore, the combination of the electric circuits shown in FIGS. 4 and 5 constitutes an anesthesia strength/concentration monitor.

In the memory IC (ROM part in FIG. 5) 46 in this electric circuit, there is a temperature/humidity sensitive element 15 that has been measured in advance.
The amount of change with respect to temperature and humidity is memorized, arithmetic processing is performed according to the procedure programmed in the memory IC 46 (see FIG. 6), and the obtained potential difference is displayed.

As shown in FIG. 6, the processing method is to multiply the amount of change in temperature and humidity in the temperature and humidity sensing element 15 by a certain multiple (for example, k) at a predetermined temperature and humidity, and then
The amount of change in temperature and humidity should be the same as the amount of change in temperature and humidity. The amount of change in the temperature/humidity sensing element 15 is then inverted and added to the amount of change in the anesthesia sensing element 10, thereby canceling out the amount of change due to temperature/humidity. Therefore, the change in the acid of the anesthetic sensor displayed by this means the change in response to the anesthetic gas.

The anesthesia sensor in this anesthesia strength/concentration monitor was exposed to 0□ gas flowing at a flow rate of m4fL/win, and humidity and halothane (1!ALOTI), a volatile inhalation anesthetic, were
FIG. 7 shows the potential difference corresponding to the change in capacitance obtained from the anesthesia sensing element 10 as the gas concentration of IANE) (CF3CHClBr) is changed, and the electrostatic capacitance obtained from the temperature/humidity element 15 is The potential difference corresponding to the change in volume is shown in FIG. 8, and the value actually displayed on the anesthesia strength/concentration monitor is shown in FIG. 9.

[Effects of the Invention] As explained above, according to the present invention, the concentration or strength of anesthesia can be directly measured without suctioning and exhausting the anesthetic gas, and the measurement is not affected by the temperature and humidity of the gas. It has the advantage of being possible.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of the anesthesia sensing element of the present invention, Fig. 2 is an enlarged cross-sectional view of the A-A' portion of Fig. 1, and Fig. 3 is an anesthesia sensor including an anesthesia sensing element and a temperature/humidity sensing element. FIG. 4 is a circuit diagram showing an electric circuit connecting the anesthesia sensing element or temperature/humidity sensing element; FIG. 5 is a block diagram following the electric circuit including the simplified diagram of FIG. 4; Figure 6 is a block diagram showing the programmed procedure, Figure 7 is a graph showing the sensitivity of the anesthesia sensing element to halothane. Figure 8 is a graph showing the sensitivity of the temperature and humidity sensing element to halothane, and Figure 9 is the anesthesia strength.・This is a graph showing the sensitivity displayed on the concentration monitor. 10... Anesthesia sensitive element, 11... Substrate, 12...
Electrode element, 14... Anesthesia sensitive substance, 15... Temperature/humidity sensitive element, 16... Adapter, 40... Anesthesia sensitive element, 42.43... A/D conversion section, 44.-I10
Conversion section 45...CPU section, 46.-ROM section, 47.
... RAM section, 48... Latch section, 49... Display section, 50.51... Electric circuit section.

Claims (1)

[Claims] (1) A temperature and humidity sensing element that is sensitive to temperature and humidity but not to anesthetic gas, which is formed by lining an electrode with a low hygroscopic substance, and a temperature and humidity sensing element that is sensitive to anesthetic gas and is not sensitive to temperature and humidity. an anesthesia sensing element configured by lining an electrode with a mixture of lecithin and a low hygroscopic substance; an electric circuit that displays the anesthesia strength or anesthesia concentration corresponding to the amount of change in the anesthetic gas; Anesthesia strength/concentration monitor characterized by offset and calibration.