CN211927449U

CN211927449U - Moisture capture equipment

Info

Publication number: CN211927449U
Application number: CN201920897780.2U
Authority: CN
Inventors: 巴尔·约霍尔; 海伦·韦斯特布鲁克
Original assignee: Cherkassia GmbH
Current assignee: Cherkassia GmbH
Priority date: 2019-06-14
Filing date: 2019-06-14
Publication date: 2020-11-13
Anticipated expiration: 2029-06-14
Also published as: WO2020249749A1

Abstract

A moisture capture device constructed by disposing a filter and desiccant material within a single-use patient mouthpiece. The device may also include a perforated foil that distributes the exhaled air flow through the desiccant material.

Description

Moisture capture equipment

Technical Field

The present disclosure relates to the field of diagnostic measurements of endogenous Nitric Oxide (NO) in exhaled breath, devices for performing such measurements, and in particular to moisture capture apparatus for preventing moisture accumulation in such devices.

Background

The discovery of endogenous NO in exhaled air and its use as a diagnostic marker for inflammation dates back to the early 1990 s (see, e.g., WO 93/05709; WO 95/02181). Today, the importance of endogenous NO is widely recognized, and the concentration of NO in exhaled breath or nitric oxide (FeNO) in exhaled breath can help identify allergy/eosinophilic inflammation, supporting the diagnosis of asthma in the absence of other objective evidence.

(AEROCRINE AB, Sweden) was the first custom-made NO analyzer used in routine clinical use in asthma patients. The first chemiluminescence-based device for detecting nitric oxide has been NIOX

(Swedish CIRCASSIA AB) and

(CIRCASSIA AB, Sweden), both of which are based on electrochemical detection.

In the summer of 1997, the European Respiratory Journal issued guidelines for standardized NO measurements (ERS task force report 10: 1683-. Shortly thereafter, the American Thoracic Society (ATS) issued clinical NO measurement guidelines (American Thoracic Society, American Lung Association medical department: Recommendations for standardized procedures for the online and offline measurement of nitric oxide and nasal nitric oxide in the exhaled lower respiratory tract of adults and children, see Am J Rapid Care Med, 1999; 160: 2104-2117). These recommendations have been updated and in 2018, the Global Asthma Initiative (GINA) promulgated a Global Asthma management and prevention strategy (reviewed in www.ginasthma.org in its entirety). However, the patient is still required to exhale for a period of time (at least 10 seconds) and at a relatively constant flow rate, preferably at a flow rate of 50ml/s ± 5 ml/s.

Endogenous NO is present in exhaled air in trace amounts, with low values of 25ppb (parts per billion) or less. Values between 25ppb and 50ppb should be interpreted carefully and referred to the clinical situation, while values above 50ppb are indicative of eosinophilic inflammation or asthma.

Maintaining accurate expiratory flow into the device is critical to maintaining accuracy of the FeNO measurement. For this reason, most diagnostic devices for measuring FeNO have built-in pressure sensors. These pressure sensors measure the flow rate of the patient's exhalation and the patient receives feedback that helps to maintain the expiratory flow within the desired interval (50ml/s ± 5 ml/s). However, performing a correct exhalation in the device requires some practice. While some patients have managed on either the first or second attempt, others require repeated attempts to achieve a successful measurement.

The exhaled breath contains water vapor. The mean water vapor amount of 10 seconds of exhalation at 24 ℃, 60% Relative Humidity (RH) was 448 μ g. If a patient encounters difficulty in making a correct exhalation, the same patient will repeatedly exhale a moist exhalation into the device for a short period of time, which may result in a moisture build-up in the device.

In some clinical settings, the frequency of use is very high. There is anecdotal evidence that up to 80 patients use some means of measuring exhaled NO during the day. Furthermore, as these devices are used in clinics around the world, some devices will inevitably be used in humid climates, such as the southern and eastern parts of china, parts of the southern united states, parts of australia, india, brazil, etc. However, moisture can present problems in colder climates. Since exhaled breath always contains moisture, it condenses when it comes into contact with cold surfaces.

These factors, alone and in combination, can lead to the accumulation of moisture in the equipment. This is a problem because once the accumulated moisture in the device reaches a certain level, the moisture starts to condense and form water droplets. The water droplets may cause clogging of the tube leading to the pressure sensor for measuring the flow rate. If water enters the pressure sensor, equipment components may be damaged.

Currently, some devices use algorithms to estimate the amount of moisture in the device and force the device to shut down when the amount of moisture becomes too high to dry it. When the device is used at high frequencies, especially in humid climates, such algorithms limit the number of measurements that can be performed before the apparatus is shut down. This is not satisfactory and it is desirable to prevent moisture from entering the apparatus.

At the same time, the sample reaching the electrochemical sensor should not dry to such an extent that it affects the sensitivity of the sensor. Electrochemical sensors for detecting nitric oxide are typically on CO₂Has a certain cross-sensitivity which increases with decreasing moisture in the sample. In fact, some sensors require at least 20% RH to function properly.

There are known solutions for capturing moisture in exhaled breath, for example by directing the exhaled breath over a surface that is cooler than the exhaled breath, resulting in condensation of moisture on the surface. Examples include the device disclosed in WO 2004/058125 entitled "Disposable hand-held device for collecting Exhaled breath condensate" and the device shown in WO 2017/153755 entitled "Exhaled breath condensate collection device and kit of parts for the same". These are effective in applications where it is of interest to analyze the coagulum itself, as the coagulum contains different substances that can serve as diagnostic markers. However, when the analyte is in the gas phase, the coagulum needs to be disposed of, and it is necessary to safely dispose of the coagulum given that the coagulum may contain infectious substances such as viruses and bacteria and thus constitute a biohazard.

Disclosure of Invention

The present disclosure provides a new, practical and surprisingly effective solution to the above-mentioned problems. According to a first aspect, the present invention provides a moisture capturing device suitable for use with an apparatus for diagnostic measurement of Nitric Oxide (NO) in exhaled breath, the apparatus comprising a handpiece for receiving exhaled breath, a passageway from the handpiece into the device, a flow sensor and/or a pressure sensor for measuring the flow and/or pressure of exhaled breath in the channel, and a sensor or sensing element that generates a detectable signal corresponding to the nitric oxide concentration in the exhaled breath, wherein the moisture capture device comprises a particulate filter material and a desiccant material, wherein the desiccant is disposed proximate the particulate filter material and within the mouthpiece, or between the mouthpiece and the channel, the mouthpiece being adapted to be attached to the hand piece such that the filter material and desiccant are located adjacent the hand piece.

According to an embodiment of the above aspect, the desiccant material is selected from the group consisting of molecular sieves, bentonite, silica gel beads, silica gel granules or particles, and combinations thereof.

According to another embodiment freely combined with the above-mentioned embodiments, the particulate filter material is selected from cellulose, cotton and glass fibers, or a combination thereof.

According to a further embodiment freely combined with the above-mentioned embodiments, the particulate filter material encapsulates the desiccant, thereby forming a composite filter pad.

According to another embodiment freely combined with the above described embodiments, the moisture capturing device comprises a perforated foil on at least one side of the filter and the desiccant, said perforations evenly distributing the breathing flow through the filter and the desiccant.

According to another embodiment freely combined with the above-mentioned embodiments, the moisture capturing device has a perforated foil on both sides, the perforations being arranged circumferentially in the foil on one side and centrally in the foil on the opposite side.

According to another embodiment freely combinable with the above described embodiments, said foil is made of aluminum or plastic, preferably aluminum.

According to another embodiment freely combined with the above-described embodiments, the mouthpiece/moisture capturing device is a single use item intended for one patient and to be discarded after use.

Drawings

The invention will be described in more detail in the following description, non-limiting examples and claims with reference to the accompanying drawings, in which:

FIG. 1 shows a device for diagnostic measurement of NO (NIOX, here Sweden CIRCASSIA AB)

) Is shown inExample, the device comprises a body 1, a handle 2, a tube 3 connecting the handle to the body, and a patient mouthpiece 4.

Fig. 2(a) and 2(b) show an example of a patient mouthpiece 4 in two perspective views, where (a) shows the patient closing his/her lips and an opening 5 into which the exhalation enters. In a second view (b) it is shown how a volume or space 6 is formed below the mouthpiece which is adapted to hold a patient filter and desiccant material between the mouthpiece and the handle.

Fig. 3 schematically shows a cross-section of a filter bag 13 containing a desiccant 16 in the form of particles or granules.

Fig. 4 schematically shows an exploded view of a moisture capturing device 10 according to an aspect of the invention, wherein the filter bag 13 is surrounded by two

perforated foils

11 and 14, wherein the perforations 12 surround the periphery of one foil and the perforations 15 are located near the center of the other foil. The perforations are not drawn to scale and the exact number, size and location of perforations may vary.

Fig. 5 shows a cross-section of the moisture capturing device 10, where the flow path is shown by white arrows, entering through the peripheral perforations 12 of the foil 11, passing through the filter material 13 and the desiccant 16, and exiting through the central perforations 15 of the foil 14.

Fig. 6 schematically shows the accumulation of moisture during use of a test setup simulating the use of the device for NO diagnostic measurements. The left and right dashed lines show moisture accumulation at 85% RH and 60% RH, respectively. At higher humidity, the accumulated moisture has reached a preset limit after three successful and one unsuccessful exhalations.

Fig. 7 is a graph showing the weight gain of different desiccant arrangements standardized for 360 uses. The two uppermost curves correspond to 19g and 14.3g of desiccant, and the three lower curves correspond to 1g, 2.7g and 2.8g of desiccant. The results show that while large amounts of desiccant showed the greatest and most sustained weight gain, small amounts of desiccant also worked well.

Detailed Description

Before the present invention is described, it is to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims and equivalents thereof.

It must be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

The term "mouthpiece" is used herein to describe the physical interface between the patient and the device used to measure endogenous NO in exhaled breath. When the test is performed, the patient exhales into the mouthpiece. The mouthpiece is for a single use and is discarded when the patient has successfully expired and has obtained a FeNO value.

According to a first aspect, the present disclosure provides a moisture capturing device adapted for use with an apparatus for diagnostic measurement of Nitric Oxide (NO) in exhaled breath, the device comprising a mouthpiece for receiving exhaled breath, a channel leading from the mouthpiece to the device, a flow sensor and/or a pressure sensor measuring the flow and/or pressure of exhaled breath in the channel, and a sensor or sensing element generating a detectable signal corresponding to the concentration of nitric oxide in the exhaled breath, wherein the moisture capturing device comprises a particulate filter material and a desiccant material, wherein the desiccant is arranged in close proximity to the particulate filter material and within the mouthpiece or between the mouthpiece and the channel, the mouthpiece being adapted to be attached to the hand piece such that the filter material and desiccant are located in the vicinity of the hand piece.

According to an embodiment of the above aspect, the desiccant material is selected from the group consisting of molecular sieves, bentonite, silica gel beads, silica gel granules and combinations thereof. Preferably, the desiccant material is a food grade silica gel material, which may be in the form of beads, granules or particles. Silica gels of many different qualities are available from many suppliers, for example from

(Merck pharmaceutical company, Darmstadt, Germany (MERCK KGaA, Darmstadt, Germany)).

According to another embodiment freely combined with the above-mentioned embodiments, the particulate filter material is selected from cellulose, cotton and glass fibers, or a combination thereof. Particulate filter materials are available from various suppliers, such as acoustic Filtration, inc (GVS Filtration, Findlay, OH, USA), worldwide, findeli, ohio.

According to a further embodiment freely combined with the above-mentioned embodiments, the particulate filter material encapsulates the desiccant, thereby forming a composite filter pad. The two circular sheets of filter material may be joined at the edges, for example glued or heat sealed, to form a mat encapsulating the desiccant material. The filter material may also be bonded throughout the pad in a quilt-like manner to minimize migration of the desiccant material.

According to another embodiment freely combined with the above described embodiments, the moisture capturing device comprises a perforated foil on at least one side, the perforations evenly distributing the flow of breathing gas through the filter.

According to another embodiment freely combined with the above described embodiments, the moisture capturing device has perforated foils on both sides, the perforations being arranged circumferentially along the foil on one side and centrally in the foil on the opposite side.

According to another embodiment freely combinable with the above described embodiments, said foil is made of aluminum or plastic, preferably aluminum. The holes may be punched or laser cut using techniques well known to those skilled in the art. The exact size, number and location of the apertures may be optimized to distribute the exhaled air flow through the entire volume of desiccant material.

When the patient exhales into the handpiece through the mouthpiece, the exhalation further enters the device for diagnostic measurement of nitric oxide through the handpiece, the exhalation phase being only 10 seconds. During exhalation, only a small portion of the moisture in the exhaled air is absorbed by the desiccant. Instead, moisture condenses on the surface of the handpiece. However, since the moisture trap of the present invention is arranged near the handpiece, this condensed moisture will be absorbed when the device measures and calculates the nitric oxide concentration in the exhaled breath after expiration. This phase may last 30 seconds or more after the patient has expired into the device through the mouthpiece and handpiece. The mouthpiece with the moisture trap was left in place until a successful breath was taken and the result (measured NO concentration) was displayed. During this time, the moisture trap surprisingly serves to dry the inner surface of the handpiece, wherein moisture has condensed during exhalation. This is a major advantage since condensed moisture is a more serious problem than moisture. When condensing on cooler surfaces in the handpiece, moisture forms droplets that travel in the flow channel/conduit and there is a risk of clogging and ultimately damaging components such as flow/pressure sensors. Thus, the moisture trap surprisingly has a dual function as a particle filter to protect the patient during inhalation and to "protect" the device when the patient exhales, and the desiccant sandwiched between the two layers of filter material is used to-to some extent-dry the exhaled air, but importantly to absorb and thus dry the hand piece itself after exhalation.

One advantage of the solution disclosed herein is that the moisture capturing device is easy to remove and replace, and is also economical to manufacture. By integrating the particle/patient filter into the moisture capture device, several different needs are met. The particle filter/patient filter forms a barrier between the device and the patient, thereby preventing the transmission of bacteria or viruses through the device. The filter material also serves a dual function, as a filter and a holder or envelope for the desiccant material. This allows the current patient filter to be replaced with a combined filter and desiccant assembly with no or little change to the mouthpiece.

Examples of the invention

Comparative example dew trap

The mechanical dew trap is constructed by 3D printing and assembling parts to form a convoluted flow path and a condensation chamber. The dew-water trap is connected to a tube 3 between the handle 2 and the body 1 of the device. In clinical use 20 dew traps were tested and found to function as expected, i.e. a large amount of water was collected in the condensation chamber. However, the experimental dew traps had to be opened, emptied and cleaned daily. Emptying and cleaning gets a very negative feedback to the user. Due to the potential biohazard risk, special care is required in emptying and handling the collected moisture.

EXAMPLE 1 test for pressure drop

In the experimental setup, 2g of desiccant material was included in a "bag" of filter paper and tested in a standard mouthpiece to determine if the moisture capturing device component was obstructing flow.

TABLE 1 pressure drop of respiratory handle

The results show that the moisture capturing device can be integrated into existing mouthpieces without causing any significant pressure drop.

Example 2 moisture Capacity

The test setup was constructed as follows: will NIOX

The handle and mouthpiece were connected to a sealed climate chamber, generating hot and humid air at approximately 35 ℃ and 97% RH to simulate the breathing of a patient. Air was drawn at a constant rate of 3l/min using a vacuum pump, and the flow was manually adjusted using a flow meter and a fine flow controller. Upon exiting the handle and mouthpiece, the wet air stream enters directly into the cooled condensate collection chamber. According to the current NIOX

The duration of the user manual, standard "breath" or device "use" is 10 seconds. A timer is used to ensure that the duration of the flow is equal to the number of device uses required for each individual test. Different moisture capturing devices containing different amounts of drying agent were inserted into the mouthpiece, modified if necessary, and attached to the handle. Before and after inserting the moisture capturing device into the mouthpiece, the moisture capturing device is weighed and the weight gain is taken as a measure of its effectiveness. Using a mouthpiece with a standardThe handle (without desiccant) served as the baseline. All tests were carried out according to test method DEV-TM-058-R001.

Silica gel (SiO) was tested as a fine particle or bead with a bead size of 1.4mm to 3.0mm (Clariant Co., Charlotte, NC, USA, Charlotte, N.C.)₂). The beads appeared bright orange when dried and turned dark blue when fully saturated with moisture.

Different amounts of silicone gel were weighed and either directly packed into a standard mouthpiece or packaged in a pad consisting of microfilters on both sides. The tested amounts of desiccant were 0.9g, 2.6g, 2.7g, 2.8g, 14.3g and 19.0g, which represent the maximum amount of desiccant of the current design that fills the mouthpiece. The unmodified mouthpiece and handle are used to create the baseline. With the desiccant in place, a 19.0g setting was tested, and a maximum of 780 or 7800 seconds of flow could be used. This represents an extreme case and experiment performed to observe when the desiccant stops absorbing moisture in the air. The results show that the desiccant did not turn completely blue after 180 uses (1800 seconds) when 14.3g was used, and that there was still residual desiccant capacity after 360 uses (3600 seconds) when 19.0g was used. An example of the results is shown in fig. 7.

EXAMPLE 3 modification of flow Path

In this example, a perforated protective cover or foil (item 11) as shown in fig. 4 was used to investigate whether the efficacy of the moisture capture device could be improved by changing the flow path of the exhaled breath through most of the desiccant. As shown in fig. 4, the perforations are arranged along the periphery of the foil. Experiments have shown that a moisture capturing device with 2.7g desiccant and perforated foil has a better performance than 2.8g desiccant without said foil. This is due to the more efficient flow path, which exposes the respiratory flow to more surface area of the desiccant, thus absorbing more moisture.

Example 4 amount of desiccant

The combined mouthpiece and patient filter is intended for one patient only and is discarded after use. Since a maximum of 5 to 10 exhalations may be used, it was investigated whether the amount of desiccant can be minimized, assuming that the patient encounters great difficulty in performing the correct exhalation. It can be seen that the performance of the moisture capturing device assembly containing only 0.9g of desiccant is practically equal to the performance of 19.0g of desiccant, corresponding to the first 100 seconds of 10 uses.

In summary, experiments have shown that even adding a small amount of desiccant to a microfilter placed in the mouthpiece has a significant effect of removing moisture, thereby preventing moisture from entering the device where there may be a risk of moisture accumulating and possibly damaging parts of the device or affecting the accuracy of the measurement.

Example 5 relative humidity measurement

A moisture sensor (Binder GmbH, Tuttlingen, Germany) was attached downstream of the experimental apparatus described in example 2 using a moisture capture apparatus containing 2.6g of desiccant. The humidity in the system was measured for 6 minutes every 20 seconds at a flow rate of 3 l/min. The results show that the RH rises continuously even if the desiccant unit extracts moisture from the air upstream of the measurement point. The results show that the moisture capture device containing the desiccant does not overly dry the air reaching the electrochemical sensor. Indeed, the use of a desiccant ensures that the RH in the air reaching the sensor is helped to stabilize.

Without further elaboration, it is believed that one skilled in the art can, using the present description (including the examples), utilize the present invention to its fullest extent. Moreover, while the invention has been described herein with respect to the preferred embodiments, which constitute the best modes presently known to the inventors, it should be understood that various changes and modifications as would be obvious to one having the ordinary skill in this art may be made without departing from the scope of the invention which is set forth in the claims appended hereto.

Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and not limitation, with the true scope and spirit being indicated by the following claims.

Claims

1. A moisture capturing device adapted for use with an apparatus for diagnostic measurement of nitric oxide in exhaled breath, the apparatus comprising a handpiece for receiving exhaled breath, a passage leading from the handpiece to the device, a flow sensor and/or a pressure sensor for measuring the flow and/or pressure of the exhaled breath in the passage, and a sensor or sensing element that generates a detectable signal corresponding to the nitric oxide concentration in the exhaled breath, the moisture capturing device is characterized in that the moisture capturing device comprises a particulate filter material and a desiccant material, wherein the desiccant is disposed proximate the particulate filter material and within the mouthpiece or patient filter, or between the mouthpiece and the channel, the mouthpiece being adapted to be attached to the hand piece such that the filter material and the desiccant are located adjacent the hand piece.

2. The moisture capture device of claim 1, wherein the desiccant material is selected from the group consisting of silica gel beads, silica gel microparticles, and silica gel granules.

3. The moisture capture device of claim 1, wherein the particulate filter material is selected from cellulose, cotton, and glass fibers, or a combination thereof.

4. The moisture capture device of claim 1, wherein the device comprises a particulate filter material and a desiccant material, and wherein the particulate filter material encapsulates the desiccant, thereby forming a composite filter pad.

5. The moisture capture device of claim 1, wherein the moisture capture device comprises perforated foil on at least one side, the perforations arranged to evenly distribute a flow of breath through the filter.

6. The moisture capture device of claim 1, wherein the moisture capture device has perforated foil on both sides, the perforations being arranged circumferentially in the foil on one side and centrally in the foil on the opposite side.

7. The moisture capture device of claim 5 or 6, wherein the foil is made of plastic.

8. The moisture capture device of claim 5 or 6, wherein the foil is made of aluminum.

9. The moisture capture device of any of claims 1-6, wherein the mouthpiece/moisture capture device is a single use item.

10. The moisture capture device of claim 7, wherein the mouthpiece/moisture capture device is a single use item.

11. The moisture capture device of claim 8, wherein the mouthpiece/moisture capture device is a single use item.