Patent Description:
Apparatuses for measuring values indicative of a patient's respiratory capacity are known.

These measurement apparatuses have often been used in the past to better understand the dynamics of basic physiological mechanisms and to delineate the physiology of respiratory mechanics.

However, the same apparatuses are still widespread and are also used in clinical practice, for example to monitor mechanical ventilation, spontaneous or assisted breathing of a patient.

In particular, these apparatuses have proved to be very useful in detecting the presence of diaphragmatic paralysis and in making an assessment of the respiratory work during mechanical ventilation.

They are therefore widely used in intensive care units, where monitoring respiratory mechanics by observing the patient's ventilation and breathing pattern is vital. The most commonly used apparatuses in this context are those for measuring oesophageal and gastric pressure, which allow a doctor to determine the values of pleural pressure and abdominal pressure and to analyse the pulmonary and thoracic compliance (distensibility) of the patient under examination.

These apparatuses typically use an oesophageal balloon associated with a catheter, through which the balloon is introduced nasally up to the patient's oesophagus. Once the oesophageal balloon has been introduced, it can be properly inflated, after which pressure measurements can begin.

However, this solution presents some criticalities, in particular regarding the invasiveness of the operation.

In fact, as specified above, apparatuses of this kind are mainly used in intensive care units, where patients are often in a condition of respiratory insufficiency. Because of this condition, patients are often connected to mechanical ventilation, or assisted breathing devices that replace or assist the normal activity of the inspiratory muscles so as to ensure that the lungs receive sufficient oxygen.

These assisted breathing devices normally make use of breathing masks or helmets that are placed on the patient's face.

It follows that the possible introduction of a catheter, possibly provided with an oesophageal balloon, inevitably proves to be a hindrance and can therefore affect the proper operation of these devices, sometimes putting the patient's health at risk.

<CIT>, for example, describes a diagnostic tool for measuring nasal cavity pressure of a patient, during both inhalation and exhalation. The diagnostic tool comprising a the nasal cannula having a pair of supply lines, each of which has a head with a discharge opening for discharging a respiratory gas. Each head is sized to be inserted within one of the nasal cavities of the patient. The tool comprises a pressure sensing probe associated with each head. Each of the pressure sensing probe is coupled to a pressure sensing device to provide a pressure reading.

The diagnostic tool described in this document should only be associated with the patient during measurement tasks because, the introduction of the head, as well as catheters and oesophageal balloons, by nasal or oral route, in order to measure respiratory pressure, is very invasive and often causes great discomfort to the patient.

Experience is required for the proper positioning of the oesophageal tube which limits the widespread use of the procedure in non-intensive settings.

Finally, the device in question is burdened by high costs since it is a singlepatient device that cannot be reused.

The object of the present invention is to solve or at least mitigate the above-mentioned drawbacks, within a simple, rational and relatively low cost solution. This and other objects are reached by the characteristics of the invention as set forth in the independent claims. The dependent claims outline preferred and/or particularly advantageous aspects of the invention.

In particular, an embodiment of the present invention makes available an apparatus for detecting and monitoring nasal pressure comprising:.

In this way, the invention is presented as a practical and minimally invasive solution for performing a correct measurement of respiratory pressure.

Thanks to this invention it is in fact possible to measure the respiratory pressure without using any oesophageal catheter and therefore without interfering with any artificial or assisted breathing devices and with less discomfort for the patient, especially during the insertion step.

In particular, the invention offers the significant advantage of making use of a nasal probe to be housed at the level of the nostril and therefore with a low level of invasiveness.

After insertion, this nasal probe can be left in place for a prolonged time, even during assisted ventilation and/or in conjunction with the presence of other therapeutic instruments that need to be positioned on the patient's face.

With the inflatable membrane in a deflated configuration, air will be able to pass freely through the through opening of the support ring, allowing the patient to breathe normally.

Only when it becomes necessary to take the measurement, it is possible to inflate the membrane and obstruct the through opening and then the nostril, allowing the pressure transducer to effectively measure the respiratory pressure through the cannula.

In this way, the invention provides the possibility to perform multiple, continuous measurements of the patient's respiratory effort without interfering with the patient's spontaneous breathing.

This solution is also advantageous in that it has a housing seat that is adapted to accommodate and support the end of the cannula, thus preventing any discomfort to the patient.

The nature of the invention also allows the probe to be easily and quickly removed from the patient's nostril, for example in case of respiratory emergencies and, more generally, if there is a need to use the nostril for other procedures such as bronchoscopies, nasal tracheal intubations or nasogastric tube positionings. In the latter case, the probe can be removed and positioned on the contralateral nostril, so as to ensure the measurement of the patient's breathing capacity.

According to an aspect of the present invention, the support ring of the nasal probe may comprise a first internal annular portion and a second external annular portion of lower stiffness than the first annular portion, which second annular portion externally covers the first annular portion and defines the external surface adapted to come into contact with the patient's nostril.

In this way, the first portion can perform an essentially structural function, necessary to keep the cannula inside the patient's nostril, while the second portion can reduce the discomfort for the patient, adapting at least partially to the shape of the nostril.

By way of example, the first annular portion of the support ring may be made of plastics while the second annular portion may be made of rubber.

Rubber is in fact a sufficiently soft and non-irritating material so as not to cause discomfort to the patient, whereas plastics has the characteristics of stiffness and solidity necessary to offer a valid support to the cannula.

Going into more detail, one aspect of the invention provides that the nasal probe may comprise an eyelet provided with an internal surface and with an external surface, wherein the internal surface of the eyelet defines the housing seat of the cannula, and wherein the through opening is instead delimited between the external surface of said eyelet and an internal surface of the support ring.

This aspect provides a rather simple and rational solution to realize both the through opening and the accommodating seat for the cannula, inside the support ring.

In this context, an embodiment of the invention provides that the eyelet of the nasal probe may be arranged coaxial to the support ring and is connected to the latter by at least one connecting element.

In this way, the cannula remains substantially equidistant from the walls of the nostril, reducing the possibility of creating a discomfort to the patient. According to a different embodiment, the eyelet of the nasal probe can be abutted to the support ring and thus partially integrated therewith.

This allows both the external ring and the eyelet to be made as one compact body, making the nasal probe more solid and stable, as well as making it easier to manufacture.

According to a different aspect of the invention, the inflatable membrane may be fixed to the internal surface of the support ring and may be adapted to expand towards external surface of the eyelet.

In other cases, the inflatable membrane may alternatively be fixed to the external surface of the eyelet and be adapted to expand towards the internal surface of the support ring.

Both of these solutions ensure an effective closure of the through opening, favouring the correct operation of the apparatus and the correct measurement of the pressure values.

These solutions also ensure that the membrane does not impede breathing when deflated.

Another aspect of the invention provides that the apparatus may further comprise a system for inflating and deflating the inflatable membrane, for example by means of an air syringe.

This solution allows a user, such as a doctor, to move the inflatable membrane between the first and the second configuration and vice versa, quickly and easily. According to another aspect of the invention, the apparatus may further comprise a pressure transducer connected with the cannula, which can be configured to measure a pressure difference between an inhalation phase and an exhalation phase.

This pressure transducer will obviously not be housed inside the nasal probe but will be an external instrument, for example one of those pressure transducers normally present in hospitals or possibly a device (monitor) specifically dedicated to the apparatus in question.

Another embodiment of the present invention finally makes available a method for detecting and monitoring nasal pressure of a patient, which comprises the following steps:.

Taking advantage of the apparatus described above, this method essentially achieves the same advantages, namely those of allowing a measurement of respiratory pressure, without interfering with other respiratory apparatus and with less discomfort for patients.

The simplicity of positioning in an external cavity makes it easier to learn the method in question, making the instrument more distributable even in areas with lower care intensity but which also treat patients with respiratory insufficiency.

Further characteristics and advantages of the invention will become clear from reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the accompanying tables.

With particular reference to the aforementioned figures, an apparatus for detecting and monitoring the nasal pressure of a patient has been globally indicated as <NUM>. More specifically, the apparatus <NUM> in question is configured to obtain a measurement of a differential of nasal pressure between an inhalation phase and an exhalation phase, which is then intended to be analysed in order to provide an indication of the patient's respiratory capacity.

As illustrated in <FIG>, the apparatus <NUM> comprises first of all a nasal probe <NUM> adapted to be stably placed within a nostril of the patient.

More precisely, the nasal probe <NUM> is designed to be inserted into the nostril and to stably remain there until it is necessary to remove it, for example due to any operations that require the use of the nostril in which it has been positioned. The nasal probe <NUM> has a support ring <NUM>, for example a cylindrical shaped body, which develops longitudinally along a central axis A from a first end <NUM> to a second end <NUM> (see <FIG>) and which is adapted to come into contact with the patient's nostril, when the nasal probe <NUM> is inserted.

Given the insertion mode of the nasal probe <NUM>, which is designed to be slidingly inserted into the patient's nostril, one of the first end <NUM> and the second end <NUM> of the support ring <NUM> is intended to face inwardly of the nasal cavity, while the other end is intended to face in the opposite direction, i.e., outwardly of the patient's nostril.

The support ring <NUM> generally comprises an internal surface <NUM> facing radially towards the central axis A and an external surface <NUM> facing radially in the opposite direction.

These internal <NUM> and external <NUM> surfaces may have a circular cross-section centred on the central axis A.

The radial distance between the internal surface <NUM> and the central axis A is clearly greater than the distance between the central axis A and the external surface <NUM>, so that between these two surfaces the thickness of the support ring <NUM> remains defined, which may depend on the size of the patient's nostril. When the nasal probe <NUM> is inserted into a patient's nostril, the external surface <NUM> of the support ring <NUM> is intended to be in contact with the internal surface of the nostril.

Instead, the internal surface <NUM> defines a through opening <NUM>, i.e., an internal cavity extending along the entire length of the support ring <NUM>, in the direction of the central axis A.

In particular, the through opening <NUM> extends into the space included between the first end <NUM> and the second <NUM> end of the support ring <NUM>.

In this way, despite the presence of the nasal probe <NUM>, the through opening <NUM> allows flow communication between the inside and the outside of the nostril and, consequently, allows the patient to breathe through that nostril, as well. In other words, the function of the through opening <NUM> is to allow the patient to breathe through both nostrils, even if one of them is occupied by the nasal probe <NUM>.

Going into more detail, the support ring <NUM> may comprise a first internal annular portion 20a and a second external annular portion 20b (always with reference to the central axis A).

The first annular portion 20a is at a shorter distance radially from the central axis A than the second annular portion 20b and is therefore externally covered by the latter.

Due to this arrangement, the first annular portion 20a defines the internal surface <NUM> of the support ring <NUM>, while the second annular portion 20b defines the external surface <NUM>.

Since the external surface <NUM> is intended to be in contact with the nostril, the second annular portion 20b is preferably made so as to have a lower stiffness than the first annular portion 20a.

For example, the second annular portion 20b may be made of rubber, while the first annular portion 20a may be made of plastics.

In this way, the first annular portion 20a provides sufficient stiffness to ensure structural stability of the nasal probe <NUM>, while the second annular portion 20b is more comfortable for the patient.

In fact, especially during insertion of the nasal probe <NUM>, the material of the second annular portion 20b may be subjected to a slight compression to be adapted to the size and shape of the patient's nostril, so as to better accommodate the nasal probe <NUM>.

The nasal probe <NUM> further comprises a housing seat <NUM> defined within the external surface <NUM> of the support ring <NUM> and designed to house, through insertion, the end of a tubular cannula (or catheter) <NUM>.

The aforesaid housing seat <NUM> is of the type passing through, i.e., it is configured as a through hole extending along an axis B parallel to the central axis A and having opposite open ends.

In this way, the housing seat <NUM> allows the end of the cannula <NUM> to be supported within the patient's nostril, but without occluding the through opening <NUM>.

The diameter of the housing seat <NUM> may be equal to or slightly smaller than the diameter of the cannula <NUM>, so as not to hinder the insertion thereof but to be able to stably block it in place.

According to an embodiment illustrated in <FIG>, the housing seat <NUM> is defined by an eyelet <NUM>, which is placed internally to the internal surface <NUM> of the support ring <NUM>.

The aforesaid eyelet <NUM> is provided with an external surface <NUM> and with an internal surface <NUM> (with respect to the central axis A).

The internal surface <NUM> of the eyelet <NUM> defines the housing seat <NUM> of the cannula <NUM>, whereas the space included between the internal surface <NUM> of the support ring <NUM> and the external surface <NUM> of the eyelet <NUM> defines the through opening <NUM>. In particular, the eyelet <NUM> may be coaxially arranged within the support ring <NUM> such that the central axis A of the latter coincides with the axis B of the housing seat <NUM>.

In this particular conformation, the eyelet <NUM> can be securely fixed to the support ring <NUM>, or more precisely to the first annular portion 20a, by means of a connecting element <NUM>.

For example, the first annular portion 20a of the support ring <NUM>, the eyelet <NUM>, and the connecting member <NUM> may be made as a single body, that is, as a single monolithic body.

According to an alternative embodiment illustrated in <FIG>, the eyelet <NUM> may be abutted to and partially integrated with the support ring <NUM>, for example the first annular portion 20a.

In particular, the eyelet <NUM> may present itself as being part of the support ring <NUM>, or more precisely of the first annular portion 20a, being at least partially protruding from the internal surface <NUM>, radially towards the central axis A.

Also in this case, the housing seat <NUM> remains defined by the internal surface <NUM> of the eyelet <NUM>, which is always contained within the external surface <NUM> of the support ring <NUM>.

On the other hand, the external surface <NUM> of the eyelet <NUM> is coupled to the internal surface <NUM> of the support ring <NUM>, with which it substantially forms a single surface adapted to delimit the through opening <NUM>.

In both cases, the support ring <NUM> further comprises an inflatable membrane <NUM>, which is adapted to be internally associated with the support ring <NUM>.

Said inflatable membrane <NUM> is configured to be selectively moved between a first configuration and a second configuration.

In the first configuration (illustrated in the figures), the inflatable membrane <NUM> is deflated and leaves at least partially open the through opening <NUM>.

More precisely, in the first configuration, the inflatable membrane <NUM> does not completely occlude the through opening <NUM> and leaves the nostril in communication with the external environment, thus allowing normal breathing to the patient, even through the nasal probe <NUM>.

In the second configuration (not illustrated), the inflatable membrane <NUM> is inflated and completely occludes the through opening <NUM> of the support ring <NUM>, preventing breathing from the nostril housing the nasal probe <NUM>.

In particular, in the embodiments disclosed herein, the inflatable membrane <NUM> may be fixed to the internal surface <NUM> of the support ring <NUM>, for example by using an adhesive material.

In this way, when the inflatable membrane <NUM> is deflated, a portion of the through opening <NUM> remains clear.

During inflation, the inflatable membrane <NUM> expands until it completely covers the external surface <NUM> of the eyelet <NUM>, by completely occluding the through opening <NUM> of the nasal probe <NUM>.

In other embodiments (not illustrated), the inflatable membrane <NUM> could alternatively be fixed to the external surface <NUM> of the eyelet <NUM> so as to expand during inflation until it completely covers the internal surface <NUM> of the support ring <NUM>. In all cases, the apparatus <NUM> may comprise an inflation and deflation system (not shown), for example but not necessarily an air syringe, by which inflation of the inflatable membrane <NUM> and deflation thereof following the measurement of the patient's nasal pressure is performed.

As illustrated in <FIG>, the apparatus <NUM> further comprises a pressure transducer <NUM> connected with the cannula <NUM>, which may be configured to measure a pressure differential between an inhalation phase and an exhalation phase of the patient.

Of course the pressure transducer <NUM> is not housed within the nasal probe <NUM> but is an external instrument.

It may, for example, be a pressure transducer of those normally present in hospitals or a device (monitor) expressly dedicated to the apparatus <NUM>.

The cannula <NUM> is shaped like a tube possibly flexible and having two opposite open ends.

A first of these ends is coupled to the housing seat <NUM> of the nasal probe <NUM> (as specified above) while the second end is connected with the pressure transducer <NUM>, so that the latter can detect the same pressure that reigns in the patient's nostril.

The pressure transducer <NUM> is then configured to continuously convert the nasal pressure, detected through the cannula <NUM>, into an analogue electrical signal. The apparatus <NUM> may therefore comprise an analogue-to-digital converter <NUM>, which is operatively connected to the pressure transducer <NUM> and adapted to convert the analogue electrical signal into a discrete (digital) signal.

More specifically, the analogue-to-digital converter <NUM> may be configured to convert the analogue electrical signal indicative of the patient's nasal pressure into a discrete value indicative of the same pressure and/or another parameter of the patient's respiratory capacity.

In other cases, the pressure transducer <NUM> may be a digital type and thus directly provide a digital signal.

Additionally, the apparatus <NUM> may comprise a monitor <NUM>, operatively connected to the analogue-to-digital converter <NUM> or directly to the pressure transducer <NUM>, which is configured to continuously display the pressure and/or respiratory capacity value of the patient.

The monitor <NUM> and/or the analogue-to-digital converter <NUM> may be integrated with or connected to a computer <NUM>, which is configured to process and manage data produced by the pressure transducer <NUM>.

In use, the apparatus <NUM> is first of all prepared by inserting one end of the cannula <NUM> into the housing seat <NUM> of the nasal probe <NUM> and by connecting the opposite end to the pressure transducer <NUM>.

The nasal probe <NUM> is then housed within one of the patient's nostrils, where it remains until use thereof is over.

When it is necessary to measure the respiratory pressure, the inflatable membrane <NUM> is inflated so that it expands until it completely occludes the through opening <NUM> of the nasal probe <NUM>, and consequently also the nostril.

At this point, the pressure transducer <NUM> can measure, through the cannula <NUM> the nasal pressure values during at least one exhalation phase and at least one inhalation phase of the patient, from which a pressure differential between the two phases can be derived and/or calculated.

At the end of the measurement, the inflatable membrane <NUM> can be deflated so that the patient can breathe with both nostrils.

At this point, the nasal probe <NUM> can be held within the nostril so that the measurement can be repeated later.

If or when it is deemed that repeating the measurement is no longer necessary, the nasal probe <NUM> may be removed.

Claim 1:
An apparatus (<NUM>) for detecting and monitoring nasal pressure comprising:
- a nasal probe (<NUM>) adapted to be permanently placed inside a patient's nostril, wherein the nasal probe (<NUM>) comprises:
- a support ring (<NUM>) which defines inside it a through opening (<NUM>) and provided with an external surface (<NUM>) adapted to come into contact with the patient's nostril, and
- a housing seat (<NUM>) defined within the external surface (<NUM>) of the support ring (<NUM>) for housing the end of a cannula (<NUM>) adapted to be connected to a pressure transducer (<NUM>),
characterized by the fact that it comprises
an inflatable membrane (<NUM>) associated with the support ring (<NUM>) and configured to be selectively moved between:
- a first configuration, in which it is inflated and completely occludes the through opening (<NUM>), and
- a second configuration, in which it is deflated and leaves at least partially open the through opening (<NUM>).