ES2861553A1 - Negative cyclic pressure room providing controlled mechanical ventilation to multiple patients without ventilators (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The negative cyclic pressure room provides controlled mechanical ventilation to one or multiple patients simultaneously, without individual positive pressure ventilators. It is developed during the SARS-CoV-2 pandemic crisis in 2020, to solve the shortage of individual positive pressure respirators. In addition to in an emergency situation, you can regain, for controlled mechanical respiration, the physiological advantages of negative pressure mechanical respiration. Access to the patient, for example, to perform surgery in the operating room or in the ICU, was not possible with the previous negative pressure, individual, iron lung respirators, being possible in cyclic pressure rooms. Its implantation in the ICU and operating rooms should avoid a large number of deep vein thromboses and pulmonary thromboembolisms, complications that occur with high associated mortality and relative frequency, in relation to surgery with positive pressure mechanical ventilation. The implantation of the rooms will improve the hemodynamics and argano-perfusion of patients admitted for a long time to the ICU undergoing mechanical ventilation. The system that cyclically reduces atmospheric pressure by means of extractors or hydraulic pistons, is implemented in hermetic rooms accessible by means of locks, which can be an operating room, or an ICU, or rooms specifically such as in the emergency of the SARS-CoV-2 pandemic. The airway of each intubated patient remains connected to the outside through an adequate filtering, heating and humidification system or to a constant pressure reservoir. Thus, without the need for a positive pressure respirator, physiological air and hemodynamic flows are established. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Negative cyclic pressure room providing controlled mechanical ventilation to multiple patients without ventilators

Technical sector

Medicine, intensive care, anesthesia, mechanical ventilation, assisted respiration.

Background of the invention

Mechanical ventilation is a life support method widely used in clinical situations of impaired respiratory function, of intra- or extra-pulmonary origin.

It must be applied in Intensive Care Units, although its use is eventually required in emergency services, in transporting critical patients, and in general, in life-threatening conditions.

This invention is based on and is a tribute to the creators of the old negative pressure respirators today in disuse due to their practical drawbacks; noisy, bulky, heavy, difficult to transport and that confined the patient inside.

The first respirators were negative pressure, manual respirators like the one built by Jones in 1864, or by Wollez in 1876, predecessors of the electric ones of the Drinkeren 1920, which Emerson improved upon.

Known as "iron lungs" they fell into disuse from 1952 when Professor Lassen in Copenhagen, given the shortage of those, made the heroic decision to ventilate his patients, polio patients, with paralyzed respiratory muscles, through a tube endotracheal through which the pressurized air was introduced from a manual balloon, which was handled by students and nurses taking turns 24 hours a day.

With this system to which the "pulmotor" that Draguer had built in 1907 and which mechanically ventilated an oro-nasal mask was later adapted, positive pressure ventilation began, the only one carried out today.

Explanation of the invention

This invention updates negative pressure assisted breathing, eliminating the inconveniences for which it was abandoned. The patient is freed from confinement within a machine (iron lung), creating a pressure set in a large environment, such as an operating room, an ICU or a large room specially created where numerous patients can be ventilated, which is convenient in the case of the current SARS-CoV 2 pandemic.

The system is characterized in that the patients are in hermetic rooms, accessible by means of locks, the atmospheric pressure in the room being variable, cyclically negative with respect to the external pressure.

The variation of the pressure in the room, together with an external air inlet circuit connected to each patient, constitutes a negative pressure mechanical ventilation system that can ventilatory assistance to as many patients as desired to be accommodated within. the room, so that all patients will receive the same pressure and will match their breathing to that established in the room, maintaining the premise that the patients in each room should have approximately similar body size.

Preferred embodiment of the invention

The deployment of the ward is relatively straightforward, and ventilatory support for multiple patients will be readily available. It is carried out in an airtight room accessible by means of locks. The variable negative pressure is obtained by connecting an adjustable depressurization system, such as that constituted by a powerful adjustable extractor that moves the air from the room to the outside.

An air inlet pipe from outside the room is available for each patient, connected to their airway.

These lines are common with those of the other patients for most of their route and are provided with the corresponding directional valves and filters.

They end on the patient's side in a T that connects at each of its three ends: 1) to the aforementioned air inlet tube, with its unidirectional valve and filter,

2) to the atmosphere of the room with filter and directional valve and

3) to the patient's airway using any of the following options

a) a tracheal intubation, in sedated and myorelaxed patients

b) a laryngeal mask, in sedated and myorelaxed patients

c) a CPAP-type mask or snorkel-type mask that covers the nose and mouth in conscious patients, who will receive the respiratory aid provided by the pressure set in the room and consciously synchronizing their own breathing with the corresponding cycle, inspiration / expiration indicated by a light or sound code that informs the cycle that is taking place.

The atmospheric pressure inside the room, negative with respect to the outside and variable, can be achieved through different methods; with compressors, pistons, pistons, aspirators ...

A convenient mechanism is an adjustable, intermittently operated exhaust fan / valve system.

For use in a large room where ICU can be mounted with more than 30 ventilated patients, we can use a cover extractor of the type used to pressurize fire escapes in large buildings, avoiding that in case of fire the stairs fill with smoke and become useless to escape. An extractor of this type can extract up to 15,000 m3 / h. As the room is hermetic, the pressure inside it will drop until we open the valve / s through which the outside air will enter or reduce the frequency of rotation of the extractor or both, recovering the initial pressure. These solenoid valves or fan speed are controlled by specific software.

In a small room of 70 m3, such as a large transport container, where an emergency ICU can be installed and up to 6 patients can be ventilated, the selected extractor would have an approximate flow rate of 1,500 M3 / h. In theoretical figures.

The pressure, negative, inside the room will drop to - 3000 / - 4000 Pa (adjustable) and will return to 0 Pa at the frequency programmed x times every minute (adjustable), this variation of the atmospheric pressure atmospheric depression of the room it is transmitted as transpulmonary pressure to each patient whose airway is connected to the outside, where the pressure is higher and constant, thus producing passive and physiological inspiratory movements, filling the pulmonary alveoli with air from outside. The pressure / time curves in each cycle and duration of the cycles are adjustable and it is of no interest to develop them here now.

As the pressure in the room decreases, the outside air enters through the individual conduits described in the lung of each patient (inspiration) and once the minimum pressure (maximum negative pressure) is reached, a valve or the decrease in the The frequency of the rotation of the extractor allows the outside air to enter the room to equalize the inside and outside pressures, reducing the patient's transpulmonary pressure to zero. As this happens, and accompanied by the elasticity and "compliance" of the lung and rib cage, the air from the patient's lung is expelled (expiration) into the room through the one-way valve and filter (for avoid contagion) connected to the aforementioned T.

Hermetic rooms can be built specifically or by adapting existing rooms. Basically making them hermetic so that there are no pressure leaks, installing the necessary conduits for the extractor of atmospheric air that will produce the negative pressure in the room and for the conduction of air to be inspired from the outside. The expired air can also be channeled to the outside through another similar conduit or released into the room once it has been filtered.

In some hospitals there are pressurized or depressurized rooms for the purpose of isolation and to avoid contamination in laboratories and operating rooms, for example by opening the doors an air flow in the direction determined by the pressure gradient. Although there are no cyclical, variable pressure rooms, there are positive pressure rooms so that outside contaminants do not enter or negative pressure rooms, so that particles do not go out. The construction of variable pressure rooms, which do not currently exist, should not entail any special difficulties. The rooms can be implemented in a container for maritime transport, trucks, buses, or in any urgent interior of construction, property or area that can be sealed so that it is hermetic.

The patients inside the room have no other impediment than the corrugated tube connected to the T and to the outside atmospheric air intake, being accessible for any treatment.

Those who are conscious and not intubated, but wearing face masks, can sit and move as far as the length of the tubes allows.

Staff working in the room or patients who do not have their airway connected to the outside can breathe normally inside the room, regardless of the local pressure cycle at any given time.

Although the room is hermetic in order to maintain the negative pressure through the extraction system, in the second half of each negative pressure cycle it lets fresh air enter through the extractor, decreasing its rotation frequency, or through a valve, to that the pressure inside the room is equal to the outside, thus the expiration of the patients and the air inside the room is renewed.

The variable negative pressure in the room should not cause great discomfort to the personnel working inside, depending on the individual sensitivity and if necessary, they may use a nasal vasoconstrictor and / or an antihistamine to avoid the effect of possible blockage of the ears that you would feel when being inside the room, since the situations of pressure variation / overpressure / atmospheric depression that they may experience become similar can cause slight discomfort in some people and be pleasant to others. The pressure variation in these rooms is the equivalent to the pressure variation inside the elevator of a skyscraper - which reaches 300m in height moving at 20m / s, about 70 KM / h or that produced inside a train car high speed, not perfectly airtight, when entering a tunnel. The aerodynamic effects of these trains when entering tunnels and their repercussions on the internal pressure of the carriages and on the passengers have been well studied.

In current and foreseeable future emergency conditions, provide assisted respiration to numerous patients.

Regardless of this rationale, negative pressure support ventilation has advantages over the positive pressure respirator system and it would be useful to implement it widely.

Since the movements and respiratory pressures with negative pressure respirators are physiological, deep vein thrombosis, pulmonary embolisms and multiorgan failure are avoided in patients undergoing intensive therapy with positive pressure ventilation for a long time.

In positive pressure respirators, the inspiratory phase (in which the lung in physiological conditions draws in air from the outside) is antiphysiological as it results in an insufflation of pressurized air that fills the alveoli instead of an inspiration or aspiration of air from the lung.

The mechanism of filling the lung with air of the positive pressure respirator, by means of positive pressure insufflation, has the disadvantage that it displaces the pulmonary alveolar circulation with decreased oxygenation and retrograde pulmonary blood flow.

Likewise, there is the inconvenience of reversing the peripheral venous blood aspiration function in the inspiratory phase, which in reality does not exist as it is insufflatory.

The hemodynamic changes and those that occur in respiratory physiology due to the substitution of inspiration for insufflation, lead to alveolar hypoperfusion, retrograde displacement of pulmonary artery flow, even with measurable displacement of the interventricular septum, reduction and impediment of venous return peripheral and from the lower limbs, with increased pressure in the vena cava, multiorgan arterial hypoperfusion, increased pressure in the cava, related to renal hypoperfusion ...

All this leads to peripheral venous thromboses and pulmonary embolisms that are prevented by heparinizing and multiorgan failure that cannot be prevented, in patients undergoing intensive therapy for a long time with positive pressure ventilation.

In the current health emergency situation this system can respond to the shortage of individual positive pressure respirators, cheaply and quickly.

These assisted breathing rooms allow total access to the patient and all the necessary elements in intensive care can be incorporated within the rooms.

Inside the room, each patient breathes through their own equipment (tracheal tube, laryngeal mask ...) and the expired air before reaching the atmosphere of the room passes through the corresponding filter, so there can be no airborne contagion . The main drawback of these rooms is that the respiratory pressure and volume cannot be directly individualized for each patient. This would require valves and additional equipment for each patient. If necessary, it can be avoided by distributing the patients in different rooms where all the patients in each have a similar size.

In the transfer of patients who need continuous ventilation, at the entrance to the room or at the exit, the ambu will function normally inside the room, a positive pressure respirator will also work that takes the air to be insufflated from the interior of the room.

At this time there are no impediments to the construction and commissioning of the rooms quickly and the constituent elements are available.

Claims (5)

1. Assisted breathing system for one or multiple patients characterized in that the patient / s is / are in a room or environment whose atmospheric pressure is made to decrease and return close to the initial one cyclically. 2. Assisted breathing system according to claim 1 in which the patient / patients have / have their airway connected to the outside of the room, where the pressure is constant, it does not drop, so that when the pressure in the room drops the rib cage and lung of the patient / s are distended and an airflow is established to the lung. 3. Assisted breathing system according to claim 1 in which the patient / patients have / are functionally connected their airway with a reservoir inside or outside the room, in which the pressure does not drop, so that when the pressure drops in the ward, the rib cage and lung of the patient / s are distended and an airflow is established from the reservoir to the lung. 4. Assisted breathing system for one or multiple patients characterized in that the patient / s is / are in a room whose atmospheric pressure is made to decrease and return close to the initial cyclically while their airway is communicated with the outside of the room in which the pressure is constant. 5. Assisted breathing system for one or multiple patients characterized in that the patient / s is / are in a room whose atmospheric pressure is lowered and resumed close to the initial one cyclically, while their airway is connected to a reservoir. inside or outside the room whose pressure does not vary.