ES2702486A1 - Weaning support device for mechanical ventilation through tracheotomy cannula (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Devices to support weaning of tracheostomized patients and connected to mechanical ventilation without the need to use a respirator, which by means of an adjustable mechanical valve that would generate as more or less allows the flow output different degrees of pressure in the airway, both in inspiration expiratory cone. The supplied flows could be humidified by connecting an active humidifier. In the same way the device presents a connecting piece for a pressure gauge that allows to know at all times the pressure that is reached in the airway (both inspiratory and expiratory). This device could avoid going directly to disconnections in "oxygen in T", in many cases not tolerated by the patient. They could also be used in intermediate units or hospitalization plants where other fans or pressure generators are not available. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Weaning support device for mechanical ventilation through a tracheostomy cannula.

Mechanical ventilation weaning support device through the application of a CPAP system (continuous airway pressure) through a tracheotomy cannula.

Object of the invention

The present invention falls within the technical field of medical devices, more specifically those that serve to support pressure through a tracheotomy cannula in patients with respiratory distress in the context of "weaning" from mechanical ventilation.

BACKGROUND OF THE INVENTION

The term "weaning" is not included in the dictionary of the Royal Spanish Academy of the Language. The term has the meaning of disconnection of mechanical ventilation (VM). However, especially in the environment of intensive care and anesthesia, it is used to describe the time that elapses between the patient's release from MV and the recovery of spontaneous breathing.

Ventilation weaning is the process in which a gradual reduction in the level of ventilatory support is made, seeking the patient to assume an effective spontaneous ventilation, after the removal of the mechanical ventilation and the artificial airway.

Within the process of disconnection of the MV, the tracheostomy is one of the weapons to achieve this goal. Only by achieving periods of prolonged disconnection of the ventilator can we finally propose to remove the tracheotomy cannula to the patient.

When a patient has been intubated in a Critical Care Unit, the use of protocols for MV removal (sedation, relaxation, non-invasive mechanical ventilation -VMNI-) is recommended in order to try extubation as early as possible, because the longer it lasts of VM there is a greater risk of complications such as pneumonia associated with mechanical ventilation (VAP).

It is also recommended to perform an early tracheostomy in patients who are suspected of requiring MV for a long time. It is therefore the tracheostomy one of the weapons to cut the times of mechanical ventilation.

The indication of the moment in which the tracheotomy should be performed in the patient undergoing prolonged intubation is still controversial today. Three decades ago, it was always planned after three weeks for the deleterious effects produced by the tubes on the tracheal mucosa. Today, its earlier use is recommended, especially since the introduction of percutaneous techniques that can be performed at the foot of the bed. Especially why in numerous studies it has been possible to demonstrate benefits on orotracheal intubation (IOT): patient comfort, communication, low levels of sedation, decrease in weaning time, oropharyngeal trauma, reintroduction of oral feeding, decrease in VAP , etc.

The tracheostomy can be performed by two different techniques:

• T racheostomy due to open surgery described by Chevalier Jackson

• Tracheostomy due to percutaneous dilatation, described by Ciaglia et al. in 1985. The latter is an alternative that allows not to perform surgical dissection. It is increasingly used in critical care services.

The potential complications of the tracheostomy could be infections, tracheal lesions and fistulas, bronchoaspiration, hypoxia, cardiac arrhythmias, hemorrhages, etc.

The goal of weaning in tracheostomized patients is to free them from their artificial airway and ensure that respiratory difficulties do not appear after decannulation. The tracheostomized patient undergoing MV presents numerous challenges for the critical care team. The patients in this process are clinically stable but, normally, they have a long time in MV, which implies the need for a multidisciplinary therapy with the help of respiratory rehabilitation equipment.

To start the disconnection of the fan, it continues to prefer modes where there is little or no control over ventilation. The CPAP mode is thus preferable if there is no hypercapnia or bad mechanical data or the support pressure modes plus PEEP (Pressure Support PEEP) guaranteeing spontaneous ventilation at all times. The inspiratory trigger must be set sensitive (± 2 Ipm), although occasionally to recover the normal diaphragmatic activity it is convenient to maintain temporary cycles with a less sensitive inspiratory trigger, around 5 Ipm. The expiratory trigger must be initially set not very sensitive (30-40% of the fall of inspiratory flow.) The support pressure will gradually decrease.

Afterwards, we try to pass to spontaneous breathing and the patient is placed in "oxygen in T." The time that should remain in this spontaneous modality should not be less than 2 hours, assessing the efficacy of cough, mobilization of secretions, tachycardia, tachypnea, anxiety, sweating, utilization of accessory muscle, rhonchi, crackles, hypoventilation, etc.

Despite the described strategies there are no devices that allow us a more gradual step of these ventilatory modalities supplied with ventilator to "oxygen in T", which in certain group of patients and situational contexts (hospitalization plants, intermediate care units) they make the weaning more laborious and prolonged in time.

When the patient is free of the respirator breathing room air certain physiological changes occur that should be explained and that would justify the use of the device that we present to avoid them.

Thus, the application of PEEP (positive pressure at the end of expiration) leads to a series of changes in pulmonary and cardiovascular function that do not differ essentially from those that were applied in respirator cycled modes than in spontaneous CPAP-like modes ( positive continuous pressure in the airway) like the one that concerns us. In fact continuous positive pressure is produced whenever a PEEP respirator is used in any of its modalities (in intubated / tracheotomized patients or not), the term is reserved exclusively for when applied with spontaneous breathing, without air insufflation under pressure.

In general, masks with a PEEP valve are used to generate CPAP, although recently an air barrier system has been introduced, without a valve (CPAP Boussignac). Figure 1.

PEEP would improve oxygenation basically by increasing CRF (Functional Residual Capacity) from an alveolar recruitment of previously collapsed units, increasing pulmonary compliance (if it does not produce overdistension) and could reduce the cardiac output. In addition, the intrapulmonary shunt would decrease and the ventilation perfusion ratio improves, producing a redistribution of the pulmonary perfusion.

At the cardiac level, PEEP may lead to a decrease in the expense by decreasing venous return, a decrease in left and right ventricular preload, an increase in right ventricular afterload and a decrease in left ventricular afterload. . The cardiac effects of CPAP have been studied in healthy subjects corroborating these claims. However, the system of interactions is very complex, sometimes giving rise to contradictory mechanisms. That is why it is important to understand well the physiological mechanisms that predominate to adequately assess individual clinical responses.

The aforementioned mechanisms are in principle valid for both CPAP and cycled with a respirator. There are, however, small differences for the same levels of PEEP used: in IPPV (mandatory ventilation by volume) there is a greater increase in intrathoracic pressure than in CPAP, produced by the increase in pressure during inspiration, while in CPAP at start the inspiration there is a slight decrease in intrathoracic pressure that would favor the venous return and the lower decrease in the expense; In addition, the transmural pressures of the left ventricle filling are greater in the CPAP than in the IPPV.

Commercial systems developed for non-invasive mechanical ventilation of CPAP with demand valves in relation to a flow system have certain drawbacks. In general, more resistance to flow as the PEEP is increased, greater pressure variation between inspiration and expiration, and greater time interval between the inspiratory effort and the start of a gas flow through the valve on demand. These disadvantages contribute to an increase in respiratory work when demand valves are used, all of which entails greater respiratory work.

In clinical practice, CPAP has been used in the treatment of respiratory failure, mainly with atelectasis, in weaning, in the syndrome of sleep apnea, in PAD (acute pulmonary edema), ARDS (adult respiratory distress). and other new applications in the context of postoperative respiratory failure.

The literature establishes a dilemma on how to provide a flow of gas adequate to the needs of the patient, either through a continuous flow or demand valves.

The demand valves open when the patient generates an inspiratory effort that is able to open them. They may be sensitive to a decrease in airway pressure or to a flow caused by the patient. Both pressure and flow are variable according to different systems. In addition, the response time of the demand valve to open (time that elapses between the beginning of the inspiratory effort of the patient and the beginning of the flow) is very variable and can mean a problem added to the patient. In addition, the work that the patient can do to obtain the mixture of air and gas can be excessive.

However, continuous flow systems do not use valves and theoretically the gas enters the patient's lung with little effort, since only a small pressure gradient is required for flow to flow between the tubing and the airway at the start of treatment. inspiration.

In the context of a tracheostomized patient, the existence of a device capable of generating an effective CPAP without the need for a respirator and facilitating the weaning of such patients is unknown. Up to the present time, it is passed directly to disconnections of "oxygen in T" or to high-flow therapies through the cannula but not generating pressure levels in the airway

Description of the invention

The aim of the invention consists of a device that would facilitate the weaning of mechanical ventilation of patients carrying a tracheostomy cannula. It consists of an open tubular, continuous flow system, in which the pressure is generated by a "MECHANICAL valve", depending on whether it is more or less open.In this continuous flow system, the pressurization must be constant, avoiding oscillations of the pressure recorded in the manometer greater than 1 cm H2O, both in inspiration and in expiration, so that to avoid pressure fluctuations during the inspiratory phase, we will compensate by increasing the gas flow in the system adjusting the rotameter of the gas mixer.

In order to modify the pressure level in the established inspiratory phase, it is enough to vary the flow of the injected gases: the greater the quantity of gas injected through the device, the greater the inspiratory pressure and vice versa; The lower the amount of gas injected, the lower the pressure generated.

To modify the level of pressure in the expiratory phase (PEEP) will be regulated by opening or closing the mechanical valve placed at the exit of the tracheostomy cannula, specifically in the distal part of the device.

In addition, the flow that is administered by the proximal part of the device through the inspiratory circuit (5) -the most proximal to the tracheotomy cannula- could be passed through an ACTIVE HUMIDIFIER, which would allow us to apply high hot and humidified flows to regulate the level of inspiratory pressure administered.

The device also has a part in the middle part with the possibility of connecting a pressure gauge that indicates at all times the pressure that is being exerted on the airway, both in inspiration and expiration and possible oscillations that occur. If not used, it has a sealing cap to prevent leakage through it.

Description of the figures

To complete the description that is being made and in order to help a better understanding of the characteristics of the invention, the present specification is accompanied as an integral part of said description, some figures in which, with an illustrative and non-limiting character, it has been represented the next:

Figure 1. Pressure / time curves showing the pressure change that occurs when using a device like the one we are dealing with.

In the left part, the pressures generated by an individual breathing under normal conditions and generating an intrathoracic negative pressure that causes the entry of air by gradient from the outside to the lungs are recorded, oscillating their pressures in the airway around 0 cm H2O . If any device with a flow that renews the air inside it and a unidirectional expiratory valve (PEEP valve) through which the exhaled air comes out, CPAP or continuous positive pressure in the airway will be generated, since an amount will be retained. of air at the end of expiration. The level of CPAP will be determined, therefore, by the PEEP valve used.

Figure 2. Application device.

Parts:

• Mechanical pressure valve Connected to the distal part (1)

• High flow gas flow meter / mixer. (6)

• Active humidifier (7)

• Humidified inspiratory circuit (5). Connected to the proximal part (3)

• Pressure gauge (4) and connection to the device part. Medial part of the device (2)

PREFERRED EMBODIMENT OF THE INVENTION

Next, a detailed explanation of a preferred embodiment of the object of the present invention is provided with the help of the figures described above.

On the tracheostomy cannula, an adjustable MECHANICAL PRESSURE VALVE would be placed, which would generate, depending more or less, on the outflow of different degrees of pressure in the airway, both in inspiration and in expiration. These pressure levels could be measured by connecting a PRESSURE GAUGE to a piece interposed between the tracheostomy cannula and the pressure valve. In the same way, the device has another connection for the INSPIRATORY CIRCUIT, which can preferably be connected to an ACTIVE HUMIDIFIER, although it would not be absolutely necessary. The CAUDALIMETER would allow us to regulate the flow that we administer through the tracheotomy cannula.

Claims (4)

1. Support devices for mechanical ventilation disconnection in patients with a tracheostomy cannula comprising the following parts: • Mechanical pressure valve • High flow gas flow meter / mixer. • Active humidifier. • Humidified inspiratory circuit. • Pressure gauge and connection to device part. 2. Mechanical ventilation disconnection support devices in patients with a tracheotomy cannula, which incorporates a mechanical pressure valve in its distal part, which allows variations in airway pressure to be more or less open. . 3. Mechanical ventilation disconnection support devices in patients with a tracheotomy cannula, which incorporates in the proximal part the inspiratory circuit through which the predetermined flow is supplied, which could be humidified if previously it has been interspersed between the inspiratory circuit and the mixer an Active Humidifier. 4. Mechanical ventilation disconnection support devices in patients with a tracheotomy cannula, which incorporates a connection piece for a pressure gauge in the medial part, which would allow us to know the pressure applied at each moment in the line aerial