RU2733970C1 - System for complex prevention of complications of artificial pulmonary ventilation - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: medical apparatus for preventing tracheal stenosis accompanying artificial pulmonary ventilation comprises a control system with a user interface comprising a programmable microcontroller, a buzzer, a light diode, liquid crystal screen with control elements, air flow sensor arranged in patient breathing circuit, remote power supply unit for 12 V and storage battery with charging device. Pneumatic circuit consists of tube with two pressure switching valves, an emergency pressure release valve, a pressure sensor and an air pump at one end and a cuff of a disposable endotracheal tube (ETT) or a tracheostomy tube (TT) connected by Luer-Lok to the apparatus at the other end of the tube. Programmable microcontroller is connected with possibility to read level of battery charge and readings of pressure sensor in cuff and flow sensor, control over air pump and pressure switching valves along feedback loop by pressure in ETT or TT cuff and flow in patient breathing circuit and to include buzzer and LED in case of emergency. Disclosed is a method for preventing tracheal stenosis in artificial ventilation using an apparatus for preventing tracheal stenosis.

EFFECT: technical result is providing prevention of tracheal stenosis during mechanical ventilation and output of secretory fluid from lower airways.

3 cl, 3 dwg

Description

A medical device for the prevention of tracheal stenosis during artificial ventilation of the lungs refers to medicine, namely to anesthesiology, resuscitation, intensive care and palliative care, and is used to prevent tracheal stenosis caused by changes in its wall under the influence of the pressure of the cuffs of endotracheal (tracheostomy or endotracheal) tubes when carrying out artificial lung ventilation (ALV).

Among the known factors leading to the occurrence of cicatricial tracheal stenosis, the main one is the effect of the endotracheal tube cuff on the tracheal wall. Compliance with the recommended pressure in the endotracheal tube cuff within 25-30 cm of water column. does not always allow to avoid damage to the mucous membrane of the trachea (Methods of treatment and prevention of cicatricial stenosis of the trachea I.S. I.S.Kurgansky, M.D. V.N. Makhutov, D.Sc. S.A. Lepekhova, BULLETIN OF OTORINOLARYNGOLOGY, 1, 2016). The cuff pressure should be limited to 45 cm of water column, otherwise the risk of necrosis of the tracheal walls increases sharply. Insufficient inflation of the endotracheal tube cuff (ETT) or tracheostomy tube (TT) cuff to pressures below 20-25 cm H2O can lead to secretion from the supra-cuff space into the lungs, which is thought to contribute to the development of enthalator-associated pneumonia (VAP) ... During anesthesia with nitrous oxide, the pressure in the cuff of ETT or TT can significantly increase due to the penetration of nitrous oxide through the wall of the cuff, which will inevitably lead to damage to the trachea due to ischemia of its mucous membrane from compression by an excessively inflated cuff. (Patent WO2011127407 USA, A61M 16 / 04. PRESSURIZED TRACHEA CUFF CONTROL ARRANGEMENT / CALDERONI Anthony, PYLANT Rogers; applicant and patentee ARM MEDICAL DEVICES INC USA. - No. PCT / US2011 / 031792; filed 04/08/2010; published 10/13/2011)

The risk of tracheal injury associated with the ETT and TT cuff is directly related to the level of cuff pressure. Current solutions for managing endotracheal tube cuff pressure require manual pressure control and regulation. This is typically accomplished by manual palpation of the pilot balloon that is located in the cuff lumen on most products from most ETT or TT tubing manufacturers. (Patent US20110253145 USA, A61M 16/04. Pressurized tracheal cuff control arrangement / Antonio Maria PESENTI, Alberto ZANELLA, Luigi CASTAGNA, Vittorio SCARAVILLI; applicant and patentee UNIVERSITA 'DEGLI STUDI DI MILANO-BICOCCA. 2016; published 10.05.2018)

Known devices for the prevention of tracheal stenosis by automatically controlling the pressure in the cuff of the endotracheal tube. These devices regulate the cuff pressure of an ETT or TT tube after the ETT or TT tube has been inserted into the patient's trachea by a breathing specialist. The specialist sets the desired cuff pressure, as a rule, within plus or minus 2 cm of water column. The device monitors the cuff pressure using pneumatic connectors in communication with a small air pump, pressure transducer, and relief valve. A pressure feedback loop with a microprocessor controller located in the regulator and control system directly controls both the air pump and the relief valve. (Intellicuff Technical specifications brochure, Hamilton medical AG, https://www.hamilton-medical.com/en_GB/Solutions/IntelliCuff-cuff-pressure-control.html) However, these devices do not solve the problem of tracheal wall stenosis, since the mucous the tracheal sheath is under constant pressure from the cuff walls.

There is a known apparatus for the prevention of tracheal stenosis (2), which coordinates the pressure level in the ETT cuff in such a way that it is maximal during the inspiratory phase and minimal during the expiratory phase. This method is used in the MythoVent ventilator. When using the MythoVent ventilator, the manufacturer has set the cuff pressure for inspiration at 25 cm H2O and expiratory pressure at 7 cm H2O, which provides regular positive pressure ventilation (https://mswestfalia.com/en/products/ anesthesiology-and-icu / mythovent /). The disadvantage of this method is the blocking of the natural mechanism of mucus removal from the walls of the LTP by the work of the villi of the ciliated epithelium of the mucous membrane, which creates conditions for the accumulation of mucus in the LTP and increases the risks of VAP development. Also, the disadvantage of this method for preventing tracheal damage can be considered the impossibility of its use in some modes of ventilation, in particular high-frequency (HFPPV), high-frequency jet (HFJV) and oscillatory (HFO, HFLO) mechanical ventilation.

In the proposed invention, these disadvantages will not be due to the complete deflation of the cuff during the exhalation phase of the patient. The air flowing out of the lungs will assist the natural secretion removal mechanism. Also, by setting the limits for regulating the pressure in the cuff, the user of the cuff can set the optimal mode of operation of the device suitable for a specific clinical situation (for example, similar to devices 1 and 2 described in this document).

The present invention includes an ETT cuff pressure regulator in synchronization with the patient's breathing rhythm. The device consists of a control system with an interface that allows you to set operating modes and displays the pressure value in the ETT cuff, a lateral air flow placed in the patient's breathing circuit and a pneumatic circuit. The device inflates the ETT or TT cuff and regulates the pressure in it after the ETT or TT is introduced into the patient's airway by a specialist. The user on the control console sets the desired pressure limits in the ETT cuff. The patented device is capable of working with any ETT or TT with a Luer-Lock connector.

The stated essence of the invention is illustrated by a description of an example of a specific implementation of the apparatus and drawings, which show:

1. Figure 1 shows the timing diagrams of the patient's respiratory cycle on mechanical ventilation and their correlation with the readings of the flow sensor and the pressure level of the ETT or TT cuff. 1 - pressure in the ETT cuff, 2 - air flow, 3 - tidal volume, 4 - inspiratory phase, 5 - expiratory phase.

2. Figure 2 schematically shows a procedure for performing mechanical ventilation of a patient's lungs using the present invention. 6 - Patent device, 7 - Endotracheal tube (ETT), 8 - ETT cuff, 9 - Patient circuit connected to the ventilator, 10 - Flow sensor, 11 - Pneumatic tube connecting the ETT cuff to the patented device, 12 - Upper airway , 13 - Lower respiratory tract, 14 - Trachea, 15 - Patient.

3. Figure 3 shows a block diagram of the invention. The pneumatic circuit (16) includes a tube having a cuff (17) located in an annular manner at one end and two pressure switching valves (18,19), an emergency pressure relief valve (20), pressure transducer (21) and air pump (22) at the other end.

The ETT or TT cuff is part of a disposable ETT or TT of a third-party manufacturer, connected to the patented device via a Luer Lock connector (23).

The pressure changeover valve is a 3-way valve.

The control system receives data on the patient's breathing phase via a flow sensor (24) located in the patient's breathing circuit.

The control system with an interface (25) consists of a microcontroller (26) connected to a liquid crystal display panel (27) with corresponding control switches. The microcontroller is programmed through the software port and reads the cuff pressure sensor readings, the flow sensor readings and the battery charge level through the analog input. The indication of the battery charge level is set by the power supply system (28), which includes an external 12V power supply unit and a battery pack with a charger. The microcontroller constantly outputs the data read through the analog port to the display panel. The microcontroller in the apparatus directly controls the air pump and pressure control valves through a pressure feedback loop. The microcontroller is directly connected to the buzzer (29) and the LED (30) signaling the alarm situation.

The pressure relief valve controls the pressure in the pneumatic circuit (and therefore the cuff pressure) independently of the microcontroller. As soon as the pressure in the cuff reaches the trigger point of the safety valve, it is released, which causes the pressure in the cuff to decrease to a safe level.

During the inspiratory phase, the microcontroller switches the pressure regulation valves to the cuff inflation and turns on the air pump until the upper preset pressure level is reached.

During the expiratory phase, the microcontroller switches the pressure regulation valves to deflation of the cuff and turns on the air pump until the lower preset pressure level is reached.

The microcontroller displays the corresponding message on the display and turns on the LED and sound signaling in the following emergency situations:

Excess pressure in the cuff by 5 cm of water column

The pressure in the cuff is lower than the set one by 5 cm of water column

Battery charge less than 11V.

During extubation (removal of ETT or TT from the patient's airway), the respiratory specialist places the ventilator in the ETT or TT cuff deflation mode. Then the microcontroller switches the pressure control valves to deflation of the cuff and turns on the air pump until the air is completely evacuated from the cuff.

The inventive device is capable of receiving data on the patient's respiratory cycle from the ventilator via a serial or parallel interface, if the ventilator has this option.

The user can set the device for 1 and 2 described in this patent for the prevention of tracheal stenosis, properly setting the boundaries of pressure changes in the ETT or TT cuff.

Thus, the described invention is a compact, simple and reliable, multifunctional medical device, which allows effective prevention of tracheal stenosis during mechanical ventilation and the natural withdrawal of secretory fluid from the nasopharynx.

The invention also allows for intermittent artificial lung ventilation in the presence of a source of constant positive pressure of the respiratory mixture (for example, a ventilator in CPAP mode) in the patient circuit by controlling the pressure in the sealing cuff, which will represent a fundamentally new ventilation mode - ventilation mode without dead space (EBMP).

Claims (3)

1. A medical device for the prevention of tracheal stenosis during artificial lung ventilation (IVL), containing a control system with a user interface, including a programmable microcontroller, a buzzer, a LED, a liquid crystal screen with control elements, an air flow sensor located in the patient's breathing circuit, a remote power supply 12 V and battery with charger, pneumatic circuit consisting of a tube with two pressure changeover valves, an emergency pressure relief valve, a pressure transducer and an air pump at one end and a cuff of a disposable endotracheal tube (ETT) or tracheostomy tube (TT), connected via a Luer-Lock connector to the device at the other end of the tube, while a programmable microcontroller is connected with the ability to read the battery charge level and the cuff pressure sensor and flow sensor, control the air pump and pressure switching valves along the feedback loop on the pressure in the cuff ETT or TT and the flow in the patient's breathing circuit and turn on the buzzer and LED in case of an emergency. 2. The medical device according to claim 1, characterized in that it is configured to obtain data on the patient's breathing phase via a serial or parallel interface. 3. A method for the prevention of tracheal stenosis during artificial ventilation of the lungs, according to which during the implementation of artificial lung ventilation the apparatus for the prevention of tracheal stenosis is used, while controlling the pressure in the sealing cuff of a disposable ETT or TT, synchronously with the patient's breathing rhythm, in the inspiratory phase pressure switching valves switch to cuff inflation and turn on the air pump until the upper pressure level is reached, and during the expiratory phase the pressure switching valves switch to cuff deflation and turn on the air pump until the lower pressure level is reached.

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