RU2729943C1 - Apparatus and method of inhalation anaesthesia - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: group of inventions relates to medical equipment. Inhalation anaesthesia apparatus comprises a ventilator and an evaporator of low-pressure anaesthetics connected by detachable connections to a respiratory circuit comprising a first safety valve, an absorber and an elastic reserve bag. Second safety valve is interconnected with the ventilating branch pipe of the artificial lung ventilation apparatus and atmosphere. Respiratory contour comprises an open and a reverse system, the elastic standby bag has a volume selected depending on the patient's size, and is located in the reversible respiratory system inside the Ambo bag to form an interstitial cavity, which is connected to the inhalation branch pipe of the artificial lung ventilation apparatus. Open system includes an evaporator connected by an inlet with an inhalation branch pipe of the ventilator apparatus. Method of inhalation anaesthesia is described.EFFECT: technical result is reduced to providing inhalation to a wide range of patients.4 cl, 5 dwg

Description

The invention relates to medical technology, namely to equipment for inhalation anesthesia (IN).

Known portable systems for conducting IN and artificial ventilation (IVL), containing multifunctional respirators with a reversible breathing circuit, - Portec (STEPHAN). The cost of the latter is 5-10 times higher than the cost of anesthetic blocks.

At the same time, simpler ventilators for resuscitation and intensive care have become widespread [SAVe ventilator with an electric drive - www.automedx.biz, pneumatic respirators - www.medprom.spb.ru]. which do not allow modern low-flow anesthesia to be performed due to the lack of a reversible breathing circuit (in these devices, the gas exhaled by the patient is released into the atmosphere).

Known apparatus IN, containing a respirator, anesthetics evaporator, connected to a breathing circuit, including an absorber, a safety valve and a reserve bag located inside the shell Ambu ("Bag in Vessel") with the formation of an inter-wall cavity connected to the inhalation pipe of the respirator [patent RU No. 2466749 , book Berlin A. Portable devices and vaporizers for inhalation anesthesia. LAMBERT / 2018, p. from. 46-48].

The shell of the Ambu can be equipped with a volumetric indicator of the excursions of the breathing bag (in the form of measured marks on the outer surface of the shell) and an adjustable limiter of the maximum volume (in the form of a clamp with oval cradles). However, the mechanical system for regulating the maximum tidal volume is structurally complex and inconvenient in operation (long-term and ambiguous adjustment), disrupting the respirator's mode of operation (with a decrease in the volume of the shell, the inhalation pressure may increase proportionally).

The present invention provides adequate administration of inhalation anesthesia and mechanical ventilation to a wide contingent of patients in almost any setting: in hospital, emergency situations and outpatient clinics, including pediatrics, dentistry and veterinary medicine.

The solution to this problem is achieved thanks to a combination of new and well-known technical solutions implemented in the patentable invention.

A portable device for inhalation anesthesia for stationary conditions contains a simple respirator and a low-resistance anesthetic vaporizer connected to a breathing circuit including an absorber, a safety valve and a reserve bag located inside the Ambu shell to form an inter-wall cavity connected to the inhalation pipe of the respirator; it is equipped with a second safety valve , the inlet of which is connected with the inter-wall cavity of the Ambu shell, and the outlet is connected with the atmosphere.

In this case, the second safety valve is equipped with an indicator for changing the patient's minute ventilation.

In emergency situations and in military field conditions, during inhalation anesthesia through an open respiratory system, the inhalation branch pipe of the respirator is connected to the inlets of the evaporator and the second safety valve.

The method of inhalation anesthesia, including the supply of air from the respirator into the inter-wall cavity of the Ambu bag and the simultaneous displacement of the respiratory mixture to the patient from the reserve bag located in it in the inhalation phase, followed by bleeding air from the inter-wall cavity into the atmosphere due to the expansion of the reserve bag in the exhalation phase, while reducing tidal volume of ventilation due to the release of air from the inter-wall cavity into the atmosphere during the inspiration phase, while simultaneously controlling the rate of delivery of the respiratory mixture to the patient. If necessary, the patient is additionally ventilated manually (increasing the respiratory rate), squeezing the reserve bag through the elastic walls of the Ambu shell in the exhalation phase of the respirator.

To expand the control range, the volume of the reserve bag is selected according to the tidal volume of a small patient.

The medico-technical result of the patentable invention is as follows:

(1) The simplest respirators for resuscitation and intensive care, including the SAVe ventilator with a fixed volume and respiratory rate, can be effectively used for inhalation anesthesia in open, half-open and half-closed breathing circuits, including low-flow anesthesia. For combined anesthesia with Xenon and Isoflurane, a closed circuit can also be used to save money.

(2) "Fixed" (according to the passport 6 l / min) minute ventilation of the SAVe respirator when working in conjunction with portable inhalation anesthesia devices (IN) "Kolibri" and vaporizers "MINIVAP" can be adjusted (reduced to 0.5 and 1 l / min, respectively) ...

This adjustment extends the scope of the SAVe respirator to patients, including small children and animals.

(3) Low resistance MINIVAP vaporizers and a “Bag in Vessel” separation chamber (a standard reserve bag in a silicone shell of the popular Ambu bag) serve as the main modules, together with the simplest resuscitation respirator (no expiratory line), portable IN / IVL systems for any breathing circuit.

(4) The semi-closed breathing circuit is isolated from the SAVe respirator and is minimized. Thereby:

- infection of the breathing circuit of the respirator is excluded;

- the risks of hypoxia and hypercapnia are reduced;

- the rate of control of the concentration of the anesthetic increases (the time of induction and awakening is reduced);

- the consumption of deficient anesthetics (Sevoflurane, Isoflurane and / or Xenon-Xe) is reduced;

- the pollution of the operating room atmosphere is reduced by reducing the emission of anesthetic vapors, including those containing halogen.

(5) The device IN "Kolibri" (evaporator "MINIVAP") is compatible with any ventilator.

(6) The mass of the IN / IVL complex is reduced several times due to the minimization of the main units (respirator and evaporator) and the elimination of metal-consuming body parts for their fastening.

The essence of the invention is illustrated by illustrations, which show:

FIG. 1 - Reversible systems of the inhalation anesthesia apparatus;

FIG. 2 - SAVe respirator + MINIVAP evaporator (open circuit)

FIG. 3 - Reserve bag inside the shell of Ambu ("Bag in Vessel");

FIG. 4 - Respirator SAVe + "Kolibri", p / z contour 22 mm (evaporator MINIVAP / S and absorber "Intersurgical");

FIG. 5 - Respirator SAVe + "Kolibri" with a 15 mm profile (MINIVAP / I evaporator and 0.6 l silicone absorber).

The device for inhalation anesthesia (Fig. 1) contains a respirator 1 and a vaporizer 2 of low resistance anesthetics (type "MINIVAP"), connected to a semi-closed breathing circuit, including a standard absorber 3, a safety valve 4 and a reserve bag 5 located inside the shell 6 Ambu with the formation the inter-wall cavity 7, connected to the inhalation branch pipe of the respirator 1, as well as the inhalation valves 8, exhalation 9 and the oxygen rotameter 10.

The apparatus is equipped with a second safety valve 11, the inlet of which is connected to the inter-wall cavity 7 of the shell 6 of the Ambu, and the outlet is connected to the atmosphere. The second safety valve 11 is equipped with an indicator for changing the patient's minute ventilation.

In an open breathing system (Fig. 2), the inhalation branch pipe of the respirator 1 is connected to the inputs of the evaporator 2 and the second safety valve 11.

The device is equipped with a 12 flow meter (tidal volume meter) of the patient.

Depending on the working conditions and the method of anesthesia, the device can be equipped with low-resistance evaporators MINIVAP / I (for patients up to 20 kg) and MINIVAP / S (for patients up to 300 kg) for different anesthetics (Sevoflurane, Isoflurane, Halothane or Enflurane).

Also, depending on the size of the patients, the volumes of the reserve bag 5 (from 50 ml to 1 l) and the shell of the Ambu 6 (300, 600 or 1200 ml) are selected.

The mass of the proposed device (IN / IVL complex) is minimal due to the minimum dimensions of the main components: respirator 1 (SAVe - weight 1.4 kg) and evaporator 2 (MINIVAP / I - weight 400 g, MINIVAP / S - 1.5 kg), rotameter 10 (Dwyer, weight 200 g), absorber 3 (200 g with a volume of 0.6 l), and the absence of massive body parts.

The device for inhalation anesthesia works as follows.

Open circuit. The branch pipe (∅22 mm) of the SAVe respirator 1 is directly connected to the inlet of the MINIVAP evaporator 2 through a standard 22F / 22M / 15M or 22F / 22M / 22M tee, the middle 22M branch pipe of which is connected to the second safety valve 11, and the inlet of the corrugated hose of the respirator 1 is non-reversible. valve and mask are connected to the outlet of the evaporator 2 (Fig. 2).

In this case, it is necessary to use a non-reversible Ruben valve with an exhalation fitting to divert anesthetic vapors outside the surgical field. The concentration of anesthetic at the outlet of the MINIVAP evaporator was measured with a RIKEN FI-21 gas analyzer with an error of ± 3% (or 0.15 vol.% At a concentration of 5 vol.%).

Minute ventilation was assessed, taking into account the respiratory rate, using flow meter 12 (laminar gas flow sensor in the form of a package of transverse discs ∅15 mm made of stainless mesh with a cell of 30 × 30 μm, graduated with a Dwyer rotameter (± 3%) and a Minihelic Dwyer differential pressure gauge (± five%).

Minute ventilation SAVe was about 5 L / min and was practically independent of the elasticity of the reserve bag - the “patient”: the readings for the free and loaded reserve bag were compared (the load with the expander was from 0.8 to 2.3 kg tangentially to the walls of the bag). In this case, the maximum inspiratory pressure was raised to 250 and 300 mm H ₂ O for the maximum loaded and free bag, respectively. The discrepancy between the experimental (underestimated by about 15-20%) and the passport (6 l / min) values of minute ventilation, apparently, is explained by the systematic error of the experimental assessment associated with the pulsating flow of the SAVe respirator.

When the second safety valve 11 is opened, releasing air in the inhalation phase of the respirator 1, the minute ventilation is accordingly reduced. With the maximum open valve 11, the minimum ventilation was MV = 1.3 l / min (25% of the maximum, P _max = 40-50 mm H ₂ O). The air discharge W _{i was} also evaluated using an additional laminar gas flow sensor.

Thus, the minute ventilation is reduced by opening the second safety valve 11 in the counterclockwise direction.

Semi-open circuit. If necessary, up to 6 l / min of additional oxygen can be supplied to the inlet of the SAVe respirator (then the O ₂ concentration reaches 62%). For this, the oxygen tube must be connected to the fitting on the upper panel of the respirator 1, under the cap "O ₂ " (in the upper right corner of Fig. 2a).

Reversible systems of the inhalation anesthesia apparatus (Fig. 1):

- Semi-closed and closed with absorber 3 and valves 8, 9 (ABC exhalation, HAV inhalation) - Pendulum with absorber 3 without valves 8, 9 (exhalation of AGV, inhalation of HAV) - Mapleson without absorber 3 and valves 8, 9 (exhalation of AGV, inhalation of HAV).

Semi-closed (closed, in the case of using super-expensive Xenon) circuit is the most economical and environmentally friendly.

During the inhalation phase, gas (atmospheric air) from the respirator 1 enters the inter-wall cavity 7 and displaces the breathing mixture from the reserve bag 5 to the patient. In the exhalation phase, the breathing mixture returns to the reserve bag 5, and the gas from the cavity 7 is released into the atmosphere. Respirator 1 here plays the role of "pneumatic hands" relative to the reserve bag 5. In this case, infection of the respiratory circuit of the respirator 1 and, accordingly, the need for its disinfection is excluded. To reduce the ventilation volume, air is vented through the second safety valve 11 from the inter-wall cavity 7 into the atmosphere during the inhalation phase, while simultaneously controlling the rate of delivery of the respiratory mixture to the patient using the flow meter 12.

(1) Semi-closed loop Ø 22 mm with Intersurgical absorber (FIG. 4).

Shell 6 Ambu with a volume of 0.6 l with a reserve bag of 0.5 l, "patient" - an additional reserve bag of 1 l, the volume of the breathing circuit of the apparatus is about 3 l. The ventilation frequency was, as a rule, 10-11 min ^-1 in all modes. If necessary, additional gas supply to the patient can be carried out manually if, in the "exhalation" phase of the SAVe respirator 1, the reserve bag 5 is squeezed through the elastic walls of the Ambu shell 6, thereby increasing the patient's ventilation rate. When the second safety valve 11 is closed, the minute ventilation SAVe is MV = 5.5 l / min and practically does not depend on the elasticity of the reserve bag - "patient's lungs" (P _max ⁼ 260-270 mm H ₂ O).

The minimum ventilation was MV = 0.9 l / min (P _max = 40-50 mm H ₂ O), while W _i = 3.1 l / min (MV + W _i = 0.9 + 3.1 = 4 l / min).

With an average setting MV = 1.9 l / min (P _max = 230 mm H ₂ O), while W _i = 2 l / min.

(2) Reducing the volume of the reserve bag 5 in the shell 6 of the Ambu further reduces the minute ventilation. Thus, when backup volume 5 of the bag (container) 100 ml of minimum ventilation averaged MV ≈ 0.4 L / min (R _max ≈1 mm H ₂ O), wherein W _i ≈ 3.6 l / min.

Example. Minute ventilation of an animal at rest is calculated based on body weight M and respiratory rate RR according to the formula MB = 10-12 ml / kg × M × RR.

Then, in a cat weighing 2 kg, minute ventilation MB = 12 ml / kg × 2 kg × 25 min ^-1 = 600 ml / min, which is slightly higher than the minimum ventilation of a respirator with a 100 ml balloon in a 600 ml separation chamber - see above (2) ...

Thus, the proposed apparatus and method provide adequate implementation of inhalation anesthesia in district hospitals, veterinary clinics and remote regions, as well as in emergency situations and military field conditions with minimal capital and operating costs.

(1) The simplest respirators for resuscitation and intensive care, for example, the SAVe ventilator with a fixed volume and respiratory rate for paramedics, can be effectively used for inhalation anesthesia through open, half-open and half-closed breathing circuits, including low-flow anesthesia. For combined anesthesia with Xenon and Isoflurane, a closed circuit can also be used to save money.

(2) "Fixed" (according to the passport 6 l / min) minute ventilation of the SAVe respirator when working in conjunction with portable inhalation anesthesia devices (IN) "Kolibri" and vaporizers "MINIVAP" can be adjusted (reduced to 0.5 and 1 l / min, respectively) ...

This adjustment significantly expands the scope of the SAVe respirator in relation to patients, including small children and animals.

(3) Low-resistance evaporators "MINIVAP" and a separation chamber "Bag in Vessel" (standard reserve bag 5 in silicone casing 6 of the popular Ambu) serve as the main modules, together with the simplest resuscitation respirator (without an exhalation line), portable IN / IVL complexes for any respiratory system.

(4) The semi-closed breathing circuit is isolated from the SAVe respirator and is minimized. Thereby:

- infection of the breathing circuit of the respirator is excluded;

- the risks of hypoxia and hypercapnia are reduced;

- the rate of control of the concentration of the anesthetic increases (the time of induction and awakening is reduced);

- the consumption of deficient anesthetics (Sevoflurane, Isoflurane and / or Xenon-Xe) is reduced;

- the pollution of the operating room atmosphere is reduced by reducing the emission of anesthetic vapors, including those containing halogen.

(5) The device IN "Kolibri" (evaporator "MINIVAP") is compatible with any ventilator.

(6) The weight of the IN / IVL complex is reduced several times due to the minimization of the main blocks and the elimination of metal-consuming body parts for their fastening.

Claims (4)

1. Apparatus for inhalation anesthesia, including a ventilator and a vaporizer of low-resistance anesthetics, connected by detachable connections to a respiratory circuit including a first safety valve, an absorber and an elastic reserve bag, characterized in that a second safety valve is introduced, communicated with the inhalation pipe of the ventilator and the atmosphere , an Ambu bag and a patient's tidal volume meter, while the breathing circuit includes an open and reversible system, an elastic reserve bag has a volume selected depending on the patient's size and is located in the reversible respiratory system inside the Ambu bag with the formation of an inter-wall cavity that is connected with a branch pipe inhalation of the ventilator, and the open system includes an evaporator connected by an inlet to the inhalation port of the ventilator. 2. A method of inhalation anesthesia, including the use of an inhalation anesthesia apparatus according to claim 1, while supplying air from the ventilator to the interwall cavity and simultaneously displacing the respiratory mixture to the patient from the reserve bag in the inhalation phase, followed by bleeding air from the interwall cavity into the atmosphere due to expansion of the reserve bag in the exhalation phase, during the inhalation phase, the tidal volume of ventilation is reduced due to the release of air from the inter-wall cavity into the atmosphere, while the rate of supply of the respiratory mixture to the patient is controlled by the flow meter. 3. The method according to claim 2, characterized in that additional ventilation of the patient is carried out manually by squeezing the reserve bag through the elastic walls of the Ambu bag in the expiratory phase of the ventilator. 4. The method according to claim 2, characterized in that the tidal volume is further reduced by reducing the volume of the reserve bag.

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