JPH01268565A - Anesthesia intensity monitor - Google Patents

Abstract

PURPOSE:To dispense with the suction and discharge of anesthetic gas and to make operation easy and safe, by bringing the anesthetic gas into contract with a substance, whose electrostatic capacity changes in response to the anesthetic gas, to measure the potential difference corresponding to the change in the electrostatic capacity and measuring anesthetic concn. or depth to display the same. CONSTITUTION:An anesthesia responsive element 10 is constituted by arranging electrode elements 12 on a substrate 11 to coat the same with an insulating layer 13 and further coating said insulating layer with a substance 14 responding to anesthetic gas. As the substance 14 responding to the anesthetic gas, lecithin is especially pref. because of its excellent response. A pulse generator 20 is constituted of a standard timer circuit 21, a capacitance 22 and a resistor 23 and sends a regular repeating pulse to a multivibrator 24. The multivibrator 24 contains a timer circuit 25 and is connected so that the pulse width of the output signal thereof is depends on the electrostatic capacity of the anesthesia responsive element. The output thereof is integrated by an integrating circuit 31 consisting of a resistor 28 and a capacitance 29 to be amplified by amplifiers 26, 27 and digitalized by a subsequent circuit to be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anesthesia strength monitor capable of measuring and displaying the depth of anesthesia or concentration of anesthesia using an anesthesia sensing element using a material sensitive to anesthetic gas.

[Prior art] Conventionally, electrocardiogram monitors have been used to monitor patients undergoing inhalation anesthesia for surgery to ensure their safety, but there are other methods that directly measure the amount of anesthetic gas inhaled. The device is not well known.

Currently, mass spectrometers and anesthesia densitometers are available as instruments for measuring anesthesia concentration.

[Problems to be solved by the invention] However, conventionally used mass spectrometers are large and difficult to calibrate, require exhaust to aspirate and sample gas, and are difficult to move due to their large size. There was a problem in that it was generally difficult to install one in each operating room due to space constraints.

In addition, conventionally used anesthesia concentration meters calculate the anesthesia concentration using the amount of anesthetic gas or infrared rays absorbed.
Furthermore, since the measurement is performed by suctioning the gas, a gas exhaust circuit is required after the measurement, and depending on the type of anesthetic gas, it may be necessary to set the type of gas on the device.

[Means for Solving the Problems] Therefore, the inventor of the present invention has focused on the problems of the conventional anesthesia meter mentioned above, and as a result of intensive studies, the present inventor has devised a method to directly measure the anesthesia concentration without suctioning and exhausting the anesthesia gas. We have discovered a simple and easy-to-use anesthesia strength monitor that can measure depth, and have arrived at the present invention.

That is, according to the present invention, the comb-shaped electrode contains lecithin, cephalin, dioctadecyl fusulfite, tristearyl phosphite, (1), 3-ditetradecylglycero-2-phosphocholine, dimethyldioctadecyl ammonium bromide, N At least one substance from the group consisting of -(β-(trimethylammonio)ethyloxybenzoyl]-dioctadecyl-L-tartamate bromide, sodium 1,2-bis(octadecyloxycarbonyl)-ethane-1-sulfonate Anesthesia sensitive element formed by lining.

Anesthetic intensity controller, characterized in that it comprises an electric circuit connected to the anesthesia sensing element and displaying the depth of anesthesia or anesthesia concentration corresponding to the amount of change in capacitance of the anesthesia sensing element with respect to the anesthesia gas. provided.

In the present invention, the substances sensitive to anesthetic gas include lecithin, cephalin, dioctadecyl phosphite, tristearyl phosphite, and ■.

3-sitetradecylglycerol 2-phosphocholine,
Dimethyldioctadecylammonium bromide, N-
At least one member selected from the group consisting of (β~(trimethylammonio)ethyloxybenzoyl)-dioctadecyl-L-glutamade-bromide, sodium 1,2-bis(octadecyloxycarbonyl)-ethane-1-sulfonate, It is particularly preferred because it has excellent sensitivity to lecithin and anesthetic gas.

Here, the depth of anesthesia refers to the degree of alveolar air pressure of an inhaled anesthetic that does not move the body due to surgical stimulation.
lveolar concentration) (
MAC). This value varies depending on the type of inhalation anesthetic, and the lower the value, the more powerful it is.

Furthermore, MAC is slightly higher in infants.

Relationship between depth of anesthesia (MAC) and anesthetic concentration (from Anesthesia Hand) Therefore, it is used as a unified reference value regardless of the type of inhalation anesthetic. In the concentration display, for example, if you put herotane in a vaporizer for etrene and do not notice the misuse, if you set a certain setting value with the dial, the concentration of herotane will be higher than the set concentration due to the difference in vapor pressure between etrene and helotane. This is extremely dangerous as it will come out of the etrene vaporizer. However, the MAC display is effective in preventing such accidents.

[Operation] Anesthetic concentration or depth of anesthesia can be measured by bringing anesthetic gas into contact with a substance whose capacitance changes in response to the anesthetic gas, and measuring the potential difference corresponding to the change in capacitance. indicate.

[Example] The present invention will be explained in more detail below based on the illustrated embodiments, but the present invention is not limited to these embodiments.

FIG. 1 shows an example of the anesthesia sensing element of the present invention, and FIG. 2 shows an enlarged cross-section IA 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 AI.
An electrode element 12 formed from a material such as the like is arranged, and an insulating layer 13 is applied to the electrode element 12. Further, a substance 14 sensitive to anesthetic gas is coated thereon.

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.

Further, the insulating layer 13 is made of an insulating material,
For example, silicon nitride (SiNx), silicon dioxide (SiO2)
Examples include.

Next, the electric circuit shown in FIG. 3 incorporating the anesthesia sensing element will be explained.

The pulse generator 20 is a standard timer circuit (NE
555) 21, a capacitance 22, and a resistor 23, the pulse generator 20 sends regularly repeated pulses to the multivibrator 24.

This multi-height regulator 24 includes a timer circuit 25 similar to the standard timer circuit 21 described above.

The connection is such that the pulse width of the output signal depends on the capacitance of the anesthesia sensing element IO. The output is integrated by an integrating circuit 31 consisting of a resistor 28 and a capacitance 29,
The signal is amplified by amplifiers (impedance modulation) 26 and 27, converted by circuits after 32, digitized, and displayed as 1.

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

(Example 1) 10 g of soybean lecithin, which is a type of lipid, was added to reagent grade 9.
It was dissolved in a beaker containing 100 g of 9.5% ethanol solution with stirring. A comb-shaped electrode was immersed vertically in the obtained solution, and after 30 seconds, it was pulled up vertically and taken out, and dried in a vacuum dryer at 500 C for 3 hours to produce an anesthesia-sensitive element consisting of a comb-shaped electrode coated with lecithin.

The above comb-shaped electrode is made of chromium-aluminum (Cr, A
M) Anode with 60 electrode elements made of alloy, about 10JLm wide, about 10Lm thick, and about 4.1ms long.

As 61 cathodes (59 wood + 2 outside), about 3m x 7
mm and is arranged and constructed on a glass-epoxy substrate. In addition, silicon nitride (SiN) is used as an insulating layer for the electrode.
x) is coated with a thickness of 0.27 Lm, and this electrode has an electrical resistance of 1 at a temperature of 21'C and a humidity of 45%.
xlo"Ω or more (applied voltage 10V), capacitance approximately 18
pF (voltage 5V, frequency 10KHz).

After lecithin was applied to this anesthesia-sensitive element consisting of a comb-shaped electrode, the capacitance increased by about 0.5 pF with one lecithin coating.

This anesthesia sensing element is connected to an electric circuit shown in FIG. 3 which is capable of outputting and displaying the capacitance of the anesthesia sensing element as a potential difference, and is also capable of adjusting the zero point of the potential difference and adjusting the gain. was created.

Next, as shown in FIG.
A volatile inhalation anesthetic, halothane, is inserted into the pipe 15 flowing at the
ane) (non-explosive fluorine compound) using a vaporizer at a concentration of 0%, 1%, 0%, 2%, 0%, 3%, 0%, 4%.
, 0%, 3%, 0%, 2%, 0%, 1%, 0%, and measured the potential difference corresponding to the change in capacitance of the anesthesia-sensitive element IO, and the graph in Figure 5 shows Indicated. Note that 16 is an anesthetic gas vaporization unit.

As is clear from the results shown in FIG. 5, it can be seen that it corresponds sensitively to the concentration of halothane and is expressed as a potential difference.

Furthermore, in the same manner, the anesthesia sensitive element 1O connected to the anesthesia intensity monitor 30 described above is inserted into the vibe 15 through which oxygen gas is flowing at a flow rate of 51/sin, as shown in FIG. Etren (Ethra), an inhaled anesthetic
ne) (non-explosive fluorine compound) using a vaporizer at concentrations of 0%, 0.7%, 0%, 1.8%, 0%, 3.7%,
Pour in the order of 0%, 1.8%, 0%, 0.7%, 0%,
The potential difference corresponding to the change in capacitance of the anesthesia sensitive element IO was measured and is shown in the graph of FIG. As is clear from the results shown in FIG. 6, it can be seen that it corresponds sensitively to the etrene concentration and is expressed as a potential difference.

Furthermore, when the results of FIGS. 5 and 6 are expressed in a graph showing the depth of anesthesia (MAC) shown in FIG. It can be seen that corresponds to the depth of anesthesia (MAC).

[Effects of the Invention] As explained above, the present invention connects an anesthesia sensing element that is sensitive to anesthetic gas to an electric circuit, and adjusts the depth of anesthesia or the anesthesia concentration in response to changes in the capacitance of the anesthesia sensing element with respect to the anesthesia gas. Since it measures and displays the anesthetic gas, there is no need to suction and exhaust the anesthetic gas, and the operation is easy and safe.

[Brief explanation of the drawing]

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 a portion taken along the line A-A' in Fig. 1, and Fig. 3 is a zero potential difference when the anesthesia sensing element of the invention is connected. An electric circuit diagram showing an electric circuit capable of point adjustment and gain adjustment. Fig. 4 is an explanatory diagram showing an example in which the anesthesia sensing element of the present invention is inserted into a vibrator. Fig. 5 shows the sensitivity of the anesthesia sensing element to the concentration of helotane. FIG. 6 is a graph showing the sensitivity of the anesthesia sensing element to etrene concentration, and FIG. 7 is a graph showing the correspondence between the depth of anesthesia and the potential difference. 10.10'...anesthesia sensitive element, 11...substrate, 1
2... Electrode element, 13... Insulating layer, 14... Anesthetic sensitizer, 15... Pipe, 16... Anesthetic gas vaporizer, 20... Pulse generator, 21... Standard timer Circuit 22... Capacitance, 23... Resistance, 24... Multivibrator-125... Timer circuit, 26.27... Amplifier, 30... Anesthesia strength monitor, 31... Integrating circuit.

Claims (1)

[Claims] (1) On the comb-shaped electrode, lecithin, cephalin, dioctadecyl phosphite, tristearyl phosphite, 1,
3-ditetradecylglycero-2-phosphocholine,
Dimethyldioctadecylammonium bromide, N-
At least one substance selected from the group consisting of (β-(trimethylammonio)ethyloxybenzoyl)-dioctadecyl-L-glutamade-bromide and sodium 1,2-bis(octadecyloxycarbonyl)-ethane-1-sulfonate. Anesthesia sensitive element formed by lining, and an electric circuit connected to the anesthesia sensitive element and displaying the depth of anesthesia or anesthesia concentration corresponding to the amount of change in capacitance of the anesthesia sensitive element with respect to the anesthetic gas. Features: Anesthesia intensity monitor.