RU2329069C2 - Anaesthetic evaporator - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: anaesthetic evaporator containing gas flow divider with parallel-plate duct on bypass lines and evaporating chamber equipped with wicks, anaesthetic concentration scale, fixed on divider, input and output.

EFFECT: evaporator is furnished with thermobarocompensator; divider is mounted horizontally inside of evaporating chamber and mechanically connected with thermobarocompensator.

7cl, 4 dwg

Description

The invention relates to medical equipment, namely to anesthetics vaporizers and inhalation anesthesia devices (IN), operating both under normal conditions of hospitals and clinics, and in emergency situations (field conditions, ambulance, etc.). The evaporator saturates the carrier gas stream (atmospheric air or compressed medical gases) with anesthetic vapors, after which the formed vapor-gas mixture is supplied to the patient.

Various designs of anesthetics vaporizers are known (RF patents Nos. 2178314, A61M 16/01, 2000; 2000817, A61M 16/18, 1991; 1810061, 1991; US patents Nos. 6526297, 600/310, 2000; 6816669, 392/397, 2004; Prince Berlin A.Z., Meshcheryakov A.V. “Narcosis and dosing of anesthetics.” M., Medicine, 1980).

Known vaporizers of anesthetics, differing in the final constructive implementation, have common characteristic significant disadvantages:

- high resistance to gas flow, which does not allow working in air (Draw-over Anesthesia) in the absence of sources of compressed medical gases;

- significant weight and dimensions (mass of modern evaporators 6-8 kg), which does not allow their use in emergency situations;

- significant losses of expensive and scarce anesthetics due to the large capacity of wicks (60-70 ml of liquid anesthetic is used only for soaking the wicks of modern evaporators at a cost of, for example, Sevoflurane 1 dollar / ml), which significantly increases the cost of operation and pollutes the workplace of the anesthetist.

Known vaporizer of low resistance anesthetics "Anesthesist-2" (device IN "Narcon-2"), is given in the USSR author's certificate No. 440016, A61M 17/00, 1974 (US patent No. 3836129, 261/47, 1974), the closest in technical essence and selected as a prototype of the patented invention.

The known evaporator allows you to work both in the presence of compressed medical gases in hospitals and clinics, and in their absence in the field.

The use of this evaporator in wide medical practice has revealed a number of significant design and operational disadvantages. In particular:

- significant weight and dimensions (weight over 3 kg);

- poor dosing stability at low gas flows (less than 2 l / min - Low Flow Anesthesia) when using modern semi-closed and closed breathing circuits;

- unsatisfactory stability of dosing of anesthetics with changing environmental pressure (highlands);

- the need for manual adjustment of the concentration in case of temperature changes.

The present invention solves the problem of increasing the stability of the dosage and the cost-effectiveness of using anesthetics while reducing weight and dimensions. The solution to this problem is achieved by a combination of new design and circuit solutions implemented in a patentable evaporator.

An anesthetic vaporizer, similar to the design described in the copyright certificate No. 440016, containing a gas flow divider in the form of slotted channels on the bypass lines and an evaporation chamber equipped with wicks, an anesthetic concentration scale attached to the divider, the input and output, according to the present invention, it is equipped with a thermal compensator , the divider is installed horizontally inside the evaporation chamber and is mechanically connected to the thermobar compensator.

The invention provides that the gas flow divider is made in the form of a tubular spool with slotted channels of variable cross-section on its outer surface and an output confuser on its inside, a core with a cowl at the inlet and a tapered tip at the outlet, and a poppet valve mounted on the core opposite the end of the spool to form an annular the gap at the outlet of the evaporation chamber, while the spool is mounted to rotate around a horizontal axis and connect slotted channels corresponding to The established concentration of anesthetic between the evaporation chamber and the bypass.

According to the invention, the temperature compensator is made in the form of a bellows with an easily evaporating liquid, one end of which is fixed on the axis of the evaporator, and the free end is connected with a core installed with the ability to move from the outlet to the entrance with increasing temperature or decreasing atmospheric pressure and reverse moving with decreasing temperature or increasing atmospheric pressure pressure.

It is envisaged that the wicks of the evaporation chamber are made in the form of triplex plates installed with a gap between themselves and symmetrically on both sides of the divider case, while the lateral elements of the triplex plates are made of porous metal and pressed against the central plate of heat-conducting metal. In this case, the divider body is located symmetrically relative to the bottom and the cover of the evaporation chamber, the inlet and outlet openings of which are located above the level of the filler neck for the anesthetic.

According to the present invention, the evaporator is equipped with a clamp containing triangular guides for vertical and horizontal handrails and slots for the evaporator body. The invention provides that its packing case is equipped with a quick-detachable mounting module, and the evaporator is filled with liquid anesthetic before transportation.

The technical result of the patented invention is as follows:

- improving the stability of dosing in a wide range of gas flow rates from 0.25 to 15 l / min, as well as atmospheric pressure from 70 kPa (3 km above sea level) to 110 kPa;

- increase the efficiency of using anesthetics by minimizing the volume of wicks (up to 3 ml);

- a qualitative reduction in mass (10-20 times) and dimensions;

- increasing the safety of dosing by eliminating the ingress of liquid anesthetic to the outlet of the evaporator when it is tilted or filled with anesthetic, which allows working in extreme situations (when transporting the patient in a helicopter, releasing from the blockage, etc.);

- more compact and convenient placement on the patient's face due to the miniature size of the evaporator (weight 300 g);

- reduction of the preparation time of the apparatus for operation due to preliminary filling of the evaporator with liquid anesthetic and assembly of the apparatus in a packing case.

The invention is illustrated by a description of an example of a constructive implementation of a patentable evaporator and drawings, which show:

figure 1 is a longitudinal section of the evaporator;

figure 2-3 - the placement of the evaporator on a vertical (top view) and horizontal handrails;

figure 4 - direct connection of the evaporator to the mask.

Patented anesthetics vaporizer contains (Fig. 1) an evaporation chamber 1 with wicks, a gas flow divider in the form of slotted channels on the lines of the evaporation chamber 1 and bypass 2, an anesthetic concentration scale attached to the divider (not shown), input 3 and output 4. Divider the gas flow is made in the form of a tubular spool 10 with slotted channels 12, 13 of variable cross-section on its outer surface and an output confuser 15 on the inner core 18 with a fairing 19 at the inlet and a conical tip 20 at the outlet and a poppet valve 22, fixed on the core 18 opposite the end of the spool 10 with the formation of an annular gap 23 at the outlet of the evaporation chamber 1, while the spool 10 is mounted with the possibility of rotation around the horizontal axis and connecting the slotted channels 12, 13 between the bypass and the evaporation chamber 1. The thermal pressure compensator is made in the form of a sealed bellows 25 with a volatile liquid 26, one end of which is fixed on the axis of the evaporator, and the free end is connected with the core 18, installed with the possibility of longitudinal movement from exit 4 to input 3 with increasing temperature or a decrease in atmospheric pressure and reverse movement with a decrease in temperature or an increase in atmospheric pressure. The wicks of the thin-walled (0.3 mm) evaporation chamber 1 are made in the form of triplex plates 30 mounted with a gap between themselves and symmetrically on both sides of the divider body, while the lateral elements of the triplex plates are made of porous metal (stainless steel) and pressed against the central plate from heat-conducting metal (copper). The divider body is located symmetrically with respect to the bottom and lid of the evaporation chamber, the inlet and outlet openings of which are located above the level of the filler neck for anesthetic (not shown). Evaporator weight 300 g.

The evaporator 33 (Fig.2, 3) is equipped with a clamp 35 with sockets 37, 38 under the housing 40 and triangular guides 42 for mounting the evaporator on the vertical 44 or horizontal 45 (stretcher 46) handrails. When using the evaporator in an open circuit in air (Draw-over Anesthesia), the evaporator can be connected directly to the patient's mask through a non-reversing valve (Figure 4). The packing case (not shown) of the portable ID device is equipped with a standard quick-release mounting module, and the patented evaporator is filled with liquid anesthetic before transportation.

The vaporizer of anesthetics works as follows. To set the desired concentration of anesthetic, the spool 10 is rotated around the axis to the corresponding scale mark, while the slotted channels 12, 13 of the corresponding length and cross section are connected to the input and output of the evaporation chamber 1. Part of the gas enters through the channels 12 to the entrance of the evaporation chamber 1, passes between the triplex plates 30 and saturates to an equilibrium concentration of anesthetic, then returns to bypass 2 through the channels 13, the annular gap 23 and is diluted at the outlet of the evaporator with the main gas stream to the desired concentration. To increase the output concentration, the spool is rotated counterclockwise, connecting slotted channels with less hydraulic resistance (shorter length and larger cross section) and vice versa. When the concentration scale is set to “0”, the evaporation chamber 1 is isolated from bypass 2.

Liquid anesthetic enters the evaporation surfaces of triplex plates 30 through the capillaries (about 10 μm) of the porous metal, as well as through gap gaps (about 20-50 μm) between the central and side plates due to the surface tension of the anesthetic. Heat to the evaporation surfaces comes from the environment through the heat-conducting walls of the evaporation chamber 1, a layer of liquid anesthetic and central copper plates.

With a decrease in the temperature of the evaporator and a corresponding decrease in the equilibrium concentration of the anesthetic, the pressure inside the bellows 25 also decreases and its free end moves the core 18 to the outlet 4 of the evaporator. In this case, the annular gap of the bypass 2 decreases, and the annular gap 23 at the outlet of the chamber increases, in turn, increasing the relative fraction of gas entering the evaporation chamber 1, eventually stabilizing the output concentration of the anesthetic. With increasing temperature, the ratio of gas flows is automatically adjusted in the opposite direction.

At the same time, the bellows acts as a baro-compensator, similarly reducing the relative gas flow through the evaporation chamber when atmospheric pressure decreases (the bellows expands) and vice versa (the bellows contracts with increasing atmospheric pressure).

Depending on the operating conditions, the evaporator 33 is placed near the patient with a clamp on a vertical 44 or horizontal 45 handrail or fixed in a box-laying, or connected directly to the mask 47 of the patient (Figure 4). Standard conical connectors allow you to quickly collect the relevant breathing circuit (open in air and half open with oxygen through a rotameter 50 for mobile use, half-closed and closed - in stationary devices of ID and artificial lung ventilation (IVL)). In emergency situations, the evaporator is connected to the patient through a non-reversing valve for 1 minute, using, if necessary, an Ambu bag for manual ventilation.

Thus, the proposed low-resistance mini-evaporator (10 mm water column at 10 l / min) provides a stable dosage of modern anesthetics (isoflurane, or fluorotane-halothane, or enflurane, or sevoflurane) in a wide range of constant and pulsating gas flows from 0.5 to 15 l / min, temperatures from 5 to 35 ° C and environmental pressures. The evaporator is economical and environmentally friendly (only 3 ml of liquid anesthetic remains on the wicks after draining). It can be installed both inside (Draw-over Anesthesia) and outside the respiratory circuit. Due to its low resistance, the evaporator is compatible with any ventilator and can also work from low-pressure oxygen sources (oxygenators).

Claims (7)

1. An anesthetic vaporizer containing a gas flow divider between the bypass and the vaporization chamber equipped with wicks, an anesthetic concentration scale mounted on the divider, an input and output, characterized in that it is equipped with a thermal pressure compensator built into the divider with the possibility of automatically controlling the gas flow ratio between the bypass and chamber when changing the temperature and gas pressure, while the divider is installed horizontally inside the evaporation chamber. 2. The evaporator according to claim 1, characterized in that the gas flow divider is made in the form of a tubular spool with slotted channels of variable cross section on its outer surface and an outlet confuser on the inner core with a fairing at the inlet and a tapered tip at the outlet and a poppet valve fixed to the core opposite the end of the spool with the formation of an annular gap at the outlet of the evaporation chamber, while the spool is mounted to rotate around the horizontal axis and connect slotted channels, corresponding boiling a prescribed concentration of the anesthetic between the evaporator chamber and the bypass. 3. The evaporator according to claim 1, characterized in that the pressure compensator is made in the form of a bellows with a volatile liquid, one end of which is fixed to the axis of the evaporator, and the free end is connected to a core installed with the ability to move from the outlet to the entrance with increasing temperature or decreasing atmospheric pressure and backward movement with decreasing temperature or increasing atmospheric pressure. 4. The evaporator according to claim 1, characterized in that the wicks of the evaporation chamber are made in the form of triplex plates installed with a gap between themselves and symmetrically on both sides of the divider body, while the lateral elements of the triplex plates are made of porous metal and pressed against the central plate of heat conducting metal. 5. The evaporator according to claim 1, characterized in that the casing of the divider is located symmetrically with respect to the bottom and lid of the evaporation chamber, the inlet and outlet openings of which are located above the filler neck for the anesthetic. 6. The evaporator according to claim 1, characterized in that it is equipped with a clamp containing triangular guides for the handrail and the socket for the evaporator body. 7. The evaporator according to claim 1, characterized in that it contains a packing case equipped with a quick-detachable mounting module, and the evaporator is filled with liquid anesthetic before transportation.

Images