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EP2067030A2 - Détecteur de dioxyde de carbone comprenant substrat de borosilicate - Google Patents

Détecteur de dioxyde de carbone comprenant substrat de borosilicate

Info

Publication number
EP2067030A2
EP2067030A2 EP07861362A EP07861362A EP2067030A2 EP 2067030 A2 EP2067030 A2 EP 2067030A2 EP 07861362 A EP07861362 A EP 07861362A EP 07861362 A EP07861362 A EP 07861362A EP 2067030 A2 EP2067030 A2 EP 2067030A2
Authority
EP
European Patent Office
Prior art keywords
carbon dioxide
dioxide detector
indicator
borosilicate
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07861362A
Other languages
German (de)
English (en)
Inventor
Rafael Ostrowski
Martin P. Debreczeny
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Covidien LP
Original Assignee
Nellcor Puritan Bennett LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/526,417 external-priority patent/US8449834B2/en
Priority claimed from US11/526,393 external-priority patent/US8431087B2/en
Priority claimed from US11/526,834 external-priority patent/US8431088B2/en
Priority claimed from US11/526,369 external-priority patent/US8420405B2/en
Application filed by Nellcor Puritan Bennett LLC filed Critical Nellcor Puritan Bennett LLC
Publication of EP2067030A2 publication Critical patent/EP2067030A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
    • G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/0057—Pumps therefor
    • A61M16/0084—Pumps therefor self-reinflatable by elasticity, e.g. resuscitation squeeze bags
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/08—Bellows; Connecting tubes ; Water traps; Patient circuits
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/08—Bellows; Connecting tubes ; Water traps; Patient circuits
    • A61M16/0816—Joints or connectors
    • A61M16/0841—Joints or connectors for sampling
    • A61M16/085—Gas sampling
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/08—Bellows; Connecting tubes ; Water traps; Patient circuits
    • A61M16/0816—Joints or connectors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/08—Bellows; Connecting tubes ; Water traps; Patient circuits
    • A61M16/0816—Joints or connectors
    • A61M16/0825—Joints or connectors with ball-sockets
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/04—Tracheal tubes
    • A61M16/0402—Special features for tracheal tubes not otherwise provided for
    • A61M16/0411—Special features for tracheal tubes not otherwise provided for with means for differentiating between oesophageal and tracheal intubation
    • A61M2016/0413—Special features for tracheal tubes not otherwise provided for with means for differentiating between oesophageal and tracheal intubation with detectors of CO2 in exhaled gases
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2230/00—Measuring parameters of the user
    • A61M2230/40—Respiratory characteristics
    • A61M2230/43—Composition of exhalation
    • A61M2230/432—Composition of exhalation partial CO2 pressure (P-CO2)

Definitions

  • the present disclosure relates to a carbon dioxide detector having a borosilicate substrate.
  • Respiratory gasses may be readily distinguished from non-respiratory gasses by carbon dioxide content. Exhaled respiratory gas in a human typically contains between 3% and 5% carbon dioxide. In contrast, ambient air has only approximately 0.03% carbon dioxide. Normal esophageal gas has similarly low levels of carbon dioxide.
  • the detection of respiratory gasses via carbon dioxide content may be useful in a variety of circumstances. For example, one may determine whether an endotracheal tube has been correctly placed in the trachea rather than in the esophagus by detecting the presence of carbon dioxide in air exiting the tube. If carbon dioxide levels consistent with respiration are present, then the tube is correctly placed. If only low carbon dioxide levels consistent with placement in the esophagus are present, then the tube may have been incorrectly placed and may need to be removed and reinserted correctly. Additionally, if a tracheal tube is present in the trachea, but carbon dioxide levels in respired gas are low, this may be indicative of perfusion failure.
  • the present disclosure relates to a carbon dioxide detector having a borosilicate substrate. [0009] In one embodiment it relates to a carbon dioxide detector having a borosilicate substrate and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate.
  • a carbon dioxide detector system having a carbon dioxide detector, a housing containing the carbon dioxide detector, and an air intake operably connected to the housing to allow air to reach the carbon dioxide detector.
  • the carbon dioxide detector may include a borosilicate substrate and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate.
  • a carbon dioxide detector system having a means for detecting carbon dioxide.
  • the means may include a borosilicate substrate. It may also include a housing means to contain the means for detecting carbon dioxide and an air intake means operably to allow air to reach the means for detecting carbon dioxide.
  • a resuscitation system having a carbon dioxide detector system, a resuscitator housing fitted with the carbon dioxide detector system, and a bag attached to the resuscitator housing.
  • the carbon dioxide detector system may have a carbon dioxide detector, a housing containing the carbon dioxide detector, and an air intake operably connected to the housing to allow air to reach the carbon dioxide detector.
  • the carbon dioxide detector may include a borosilicate substrate and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate.
  • Another embodiment relates to a method of manufacturing a carbon dioxide detector. The method may include wetting a borosilicate substrate with a carbon dioxide responsive indicator solution and drying the indicator solution to immobilize it on the substrate and form a dried carbon dioxide detector.
  • Another embodiment relates to a method of detecting carbon dioxide concentration in an air sample.
  • the method may include exposing a carbon dioxide detector to the air sample.
  • the carbon dioxide detector may include a borosilicate substrate and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate.
  • the method may also include determining the color of the indicator solution, wherein the color of the indicator solution indicates the carbon dioxide concentration in the air sample.
  • Still another embodiment relates to a carbon dioxide detector having a carbon dioxide responsive indicator solution disposed on a borosilicate substrate.
  • the detector may retain acceptable carbon dioxide sensitivity for at least 7 days at a temperature of approximately 60 0 C.
  • Another example method relates to detecting carbon dioxide in a breath-to- breath manner.
  • a carbon dioxide detector having a carbon dioxide responsive indicator solution disposed on a borosilicate substrate.
  • One may measure the carbon dioxide in respired air at an interval corresponding to every breath of the subject.
  • Yet another example method of detecting carbon dioxide includes providing an air sample to a carbon dioxide detector having a carbon dioxide responsive indicator solution disposed on a borosilicate substrate.
  • One may measure the carbon dioxide in the air sample in a time frame between approximately 1 to 20 seconds.
  • Another embodiment relates to a carbon dioxide detector having a carbon dioxide responsive indicator solution disposed on a borosilicate substrate.
  • the detector may retain acceptable carbon dioxide sensitivity during at least two hours of exposure to humid air.
  • An example method for determining whether a gaseous sample contains a predetermined concentration of carbon dioxide includes contacting the gaseous sample with a carbon dioxide detector having a carbon dioxide sensitive indicator disposed on a borosilicate substrate to detect carbon dioxide in the gaseous sample.
  • the device may include a tubular housing having one end adapted for insertion into a subject's trachea and an other end adapted for placement external of the subject, the housing defining a lumen therethrough from one end to the other end for allowing bidirectional passage of air into and out of the subject to ventilate the subject's lungs. It may also include a carbon dioxide detector having a carbon dioxide sensitive indicator disposed on a borosilicate substrate placed within the lumen for determining the presence of carbon dioxide therein while still permitting unimpeded bidirectional flow of air therethrough to ventilate the subject's lungs.
  • Yet another embodiment relates to carbon dioxide detector that includes a borosilicate substrate; and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate, wherein the indicator solution changes from purple to tan in the presence of carbon dioxide above a first level.
  • Yet another embodiment relates to carbon dioxide detector that includes a borosilicate substrate; and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate, wherein the indicator solution changes color in less than 1 second in the presence of carbon dioxide above a first level.
  • another embodiment relates to carbon dioxide detector that includes a borosilicate substrate; and a carbon dioxide responsive indicator solution disposed on the borosilicate substrate, wherein the indicator solution is adapted to change from color in the presence of carbon dioxide after a shelf life of greater than five years.
  • Figure 1 illustrates a colorimetric carbon dioxide detector according to an exemplary embodiment of the present disclosure.
  • Figure 2 illustrates another colorimetric carbon dioxide detector system according to an exemplary embodiment of the present disclosure.
  • Figure 3 illustrates a third colorimetric carbon dioxide detector system according to an exemplary embodiment of the present disclosure.
  • Figure 4 illustrates a resuscitator having a colorimetric carbon dioxide detector system according to an exemplary embodiment of the present disclosure.
  • Figure 5A shows the color transition of a previous cellulose carbon dioxide detector when exposed to room air and temperature. Light hash marks indicate yellow. Darker cross marks indicate purple.
  • Figure 5B shows the color transition of a carbon dioxide detector according to an embodiment of the present disclosure when exposed to room air and temperature. Light hash marks indicate yellow. Darker cross marks indicate purple.
  • Figure 6A shows the color transition of a previous carbon dioxide detector when aged at 60 0 C in standard packaging. Light hash marks indicate yellow. Darker cross marks indicate purple.
  • Figure 6B shows the color transition of a carbon dioxide detector according to an embodiment of the present disclosure when aged at 60 °C in standard packaging. Light hash marks indicate yellow. Darker cross marks indicate purple.
  • Figure 7 shows the response time of two carbon dioxide detectors in humid air based on yellow to purple transition during inhalation and purple to yellow transition during exhalation.
  • the present disclosure relates to a colorimetric carbon dioxide detector having a borosilicate substrate.
  • detector 10 may include substrate 12 and indicator solution 14.
  • Detector 10 may be sized appropriately for use in a detector system, such as those shown in Figures 2 and 3.
  • Substrate 12 may include any borosilicate-containing material. Specifically, it may include borosilicate fibers. These fibers may be produced using any conventional methods, such as melt blowing and spinning.
  • the substrate may include a mesh of borosilicate fibers. More specifically, it may include a thin, highly porous mesh to facilitate rapid infiltration of carbon dioxide gas into the substrate.
  • Borosilicate may be sufficiently hydrophilic to allow indicator solution 14 to spread evenly over substrate 12 and be well absorbed when it is first applied. Indicator solution 14 may then be dried, but still retain sufficient water to allow reaction with carbon dioxide. However, the borosilicate substrate may also not be so hydrophobic that its shelf-life is compromised.
  • the borosilicate-containing material may also include an acrylic binder.
  • this binder may be no more than 5% by weight or volume of the total substrate without indicator.
  • Metrigard® membranes containing acrylic binder sold by Pall Corporation (New York) or a similar acrylic binder may be used.
  • Indicator solution 14 may contain an indicator, such as a chromogenic dye, in a solution. Indicator solution may be coated onto or impregnated into substrate 12. It may have a surface exposed to or near air or gas within carbon dioxide detector 10. Indicator solution 14 may be able to respond rapidly and positively to the presence or absence of certain concentrations of carbon dioxide. More specifically, it may be able to respond to concentrations of carbon dioxide normally present in air respired from a human, such as between approximately 2% and 5% or higher. Indicator solution 14 may also be able to respond to concentrations of carbon dioxide in air respired from a human with perfusion failure, such as concentrations between approximately 0.5% and 2%. Finally, indicator solution 14 may show no response to carbon dioxide concentrations normally present in external air or esophageal air, such as concentrations below approximately 0.5% and more specifically, concentrations between 0.03% and 0.5%.
  • indicator solution 14 may show no response to carbon dioxide concentrations normally present in external air or esophageal air, such as concentrations below approximately
  • Response times to changing carbon dioxide levels in detected air may be between approximately 1 and 20 seconds. Further, a borosilicate substrate 12 may exhibit virtually instantaneous response times of less than 1 second, which is an improvement over typical colorimetric carbon dioxide detection systems. Response may include a colorimetric indication, such as change of the indicator from one color to a very distinct second color. However, once the color begins to change, the change from one color to the other color may be virtually instantaneous as seen by the human eye. [0042] In order to attain the above response properties, the indicator in indicator solution 14 may have a pK lower by 1.0-1.5 pH units than the pH of indicator solution 14.
  • indicator solution 14 allows indicator solution 14 to not change color instantly when exposed to air, allowing detector system 10 to be removed from packaging then connected to another device, such as a resuscitator.
  • another device such as a resuscitator.
  • an indicator pK outside of this range may still be acceptable. In general, any pK sufficient to allow carbon dioxide detector 10 to remain exposed to room or outside air for at least 15 minutes, at least 30 minutes, at least 60 minutes, or at least 120 minutes without significant color change may be sufficient.
  • Indicator solution 14 may include an alkaline solution containing hydroxyl ions or amine residues that react chemically with carbon dioxide to form a carbonate and/or a bicarbonate or carbamate moiety. This reaction may be represented by the following equations:
  • This reaction depletes the hydroxyl ion or amine at the interface between indicator solution 14 and air and this lowers the pH at the surface of indicator solution 14 where it is adjacent or nearly adjacent to air. This depletion results in the diffusion of new base from elsewhere in indicator solution 14 to its surface to maintain a surface pH similar to that of indicator solution 14 overall .
  • the concentration of OH " or amine in the bulk of indicator solution 14 impregnated in or coated on substrate 12 helps determine the rate of diffusion of base to the surface of indicator solution 14.
  • the rate of the chemical reaction at this surface is determined by the nature of each specific reacting species.
  • A is the indicator.
  • the balance of base between the surface and remainder of indicator solution 14 is also influenced by the contact time between the surface and the gas to which it is exposed, the composition of substrate 12, which determines the diffusivity constant for A and thus the rate of diffusion of A to the surface, and the concentration of carbon dioxide in the gas, which determines the rate of diffusion of carbon dioxide into or near the surface of the indicator where it may react with the indicator.
  • the concentration of OH " or amine in indicator solution 14, the rate of the chemical reaction, the contact time between the indicator surface and the gas and the diffusivity constant for A may all be pre-determined by the manner in which carbon dioxide detector 10 is constructed and the manner in which it is used. This leaves the concentration of carbon dioxide in the gas the only variable parameter with significant effect, allowing for its measurement.
  • the concentration of OH " or amine in indicator solution 14 and the rate of the chemical reaction may be selected such that the pH near the surface of indicator solution 14 decreases sufficiently in the presence of a certain concentration of carbon dioxide to cause a color change in indicator solution 14. For example, the color change may occur if the concentration of carbon dioxide in the tested air is greater than approximately 2%. This color change may occur within 1 to 20 seconds of exposure of carbon dioxide detector 10 to the air. In a specific example, a concentration of OH " sufficient to produce a pH of 9.6 +/- 0.2 in indicator solution 14 is sufficient to provide this sensitivity.
  • Embodiments of the present disclosure may also be utilized in areas other than breath-related carbon dioxide detectors. For example, they may be used to monitor the air in gas storage rooms, as an indicator in food packaging, as an air freshness indicator on airplanes or other areas where air is recycled, such as spacecraft, or as a room air freshness indicator for any enclosed space where a high density of people may gather. Sensitivity of the indicator solution and thus the detector may be selected to meet the needs of these and other embodiments. For example, some embodiments may need to be sensitive to and perhaps change color at different carbon dioxide concentrations than are recommended for a breath-related detector.
  • the indicator may have a pK sufficiently lower than the pH of indicator solution 14 so that a color change does not occur upon exposure to room or outside air for a certain time period. Exposure to air causes the pH at the surface of indicator solution 14 to gradually decrease, but if such decrease is sufficiently slow, the desired time period without color change limitation may still be met.
  • the indicator used may affect which base is used to provide an alkaline indicator solution 14. For example, if the pK of the indicator is too low it is possible that with certain bases the pH of the indicator will not drop low enough to cause a color change in the presence of an elevated carbon dioxide concentration. For example, when a sodium hydroxide base is used the carbonate reaction product is water soluble and also a base. This buffers a pH decrease and may prevent the pH from reaching a level able to trigger a color change in the indicating element if the indicator has a low pK.
  • Calcium hydroxide may be used as a base in embodiments of this description. Calcium hydroxide serves as a source of hydroxyl ions but its carbonate reaction product with carbon dioxide is insoluble and therefore unable to buffer indicator solution 14 against a decrease in pH. Thus calcium hydroxide may be used with indicators having relatively low pKs, such as metacresol purple rather than, for example, thymol blue or phenol phthalein. This also allows for increased resistance to color change when exposed to room or external air. However, the use of a borosilicate or borosilicate + acrylic substrate 12 may allow use of a buffering source of hydroxyl ions in indicator solution 14.
  • Various colorless compounds may be used to provide an alkaline indicator solution 14. These include, but are not limited to calcium hydroxide, sodium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, potassium carbonate, sodium barbitol, tribasic sodium phosphate, dibasic sodium phosphate, potassium acetate, monoethanolamine, diethanolamine, and piperidine. However, if an acrylic-bound borosilicate is used as a substrate, no base may be needed.
  • Various pH sensitive indicators may also be used in indicator solution 14.
  • Indicator solution 14 may also contain a hygroscopic, high-boiling, transparent, colorless, water-miscible liquid. This liquid may entrap sufficient water in indicator solution 14 when it is coated onto or impregnated into substrate 12 to allow reaction of the surface of indicator 14 with carbon dioxide present in carbon dioxide detector 10.
  • Example hygroscopic, high-boiling, transparent, colorless, water-miscible liquids that may be used in indicator solution 14 include, but are not limited to glycerol, propylene glycol, monoethylene glycol, diethylene glycol, polyethylene glycol, and aliphatic alcohols. In specific embodiments, glycerol and propylene glycol or mixtures thereof may be used because of their antiseptic and non-toxic properties. Acrylic binder used in some embodiments of the disclosure also increases the hydrophobicity of substrate 12 and may thus decrease the need for a hygroscopic, high-boiling, transparent, colorless, water-miscible liquid in indicator solution 14.
  • Indicator solution 14 may be in an aqueous solution, or it may not be in solution in water. It may require or benefit from the presence of water, or may function independently of water. Indicator solution 14 may also be any type of chromogenic agent. For example, it may be a chromogenic agent that does not go into solution in water, but that nevertheless relies on nearby water.
  • an acrylic binder When used, an acrylic binder provides a more basic environment for an indicator and also increases the hydrophobicity of the substrate.
  • a basic environment may help keep the color of the indicator appropriate in a low CO 2 , such as less than 0.5%, environment.
  • Acrylic is an electron rich compound, which makes it a good Bronstead and Lewis base. The resulting ability to accept protons from proton rich compounds and to donate a pair of electrons to electron poor compounds allows the indicator to remain unreacted. Enough carbonic acid is formed to affect the indicator, but some of the acid is reacted by the acrylic.
  • a desired ratio of proton acceptance to compound concentration may be determined for different detectors. Varying the concentration of the acrylic binder will have an effect on the amount of carbonic acid available to react with the indicator when carbon dioxide is present in larger amounts. Thus, carbon dioxide detectors 10 that also contain acrylic binder in substrate 12 may not need sodium carbonate because the binder itself may provide a more basic environment for the indicator. When acrylic binder is used, the final color of dried indicator may also be less sensitive to changes in the pH of indicator solution 14. This may allow for a decrease in the amount of indicator in indicator solution 14 by as much as approximately 66% as compared to cellulose-based carbon dioxide detectors.
  • indicator solution 14 may include 0.0169 g of cresol red, 275 mL triethylene glycol, and 725 mL deionized water. This indicator solution may lack carbonate.
  • Indicator solution 14 may be immobilized on substrate 12 by drying, which removes a substantial amount of water. However, the reaction between the indicator and carbon dioxide may require water. Therefore, some water may be absorbed by indicator solution 14 and/or substrate 12 before use. For example, water may be absorbed from ambient air. In a specific embodiment, sufficient water may be absorbed in the time period required to remove carbon dioxide detector 10 from protective packaging and begin its actual use. For example, sufficient water may be absorbed by indicator solution 14 in less than 10, 5 or 1 seconds after the opening of any protective packaging.
  • Indicator solution 14 may also be placed on substrate 12 in various other forms or using other methods. For example, it may be provided in a hydrogel. Substrate 12 may also be treated, for example by plasma treatment, prior to administration of indicator solution 14.
  • a borosilicate substrate may result in desirable response time and shelf life of a carbon dioxide detector, while retaining the capacity of the detector to cycle from one color to another quickly from breath to breath.
  • reaction of the substrate with cresol red which is used as a color indicator, eventually changes the color indicator irreversibly from purple to yellow. This change makes the detector color insensitive to the presence or absence of carbon dioxide. As a result, the detector system is no longer functional.
  • packaging can help prevent this sensor aging, it nevertheless may limit shelf life. Borosilicate substrates do not react with cresol red.
  • the same shelf life as is obtained with other substrates may be achieved with borosilicate and more cost effective packaging, or, a longer shelf life even in the same packaging may be achieved.
  • the shelf life of a borosilicate-based carbon dioxide detector may be greater than 5 years, great than 10 years, or greater than 14 years.
  • the packaging employed may be reduced, due to the stability of the borosilicate-based carbon dioxide detector.
  • a borosilicate-based carbon dioxide detector may achieve a long shelf life (e.g. several years) without the use of a dessicant.
  • the borosilicate substrate 12 may exhibit an improved color cycling pattern in the presence of carbon dioxide.
  • a common indicator solution 14 such as metacresol purple
  • the substrate 12 may change from a deep purple to a light tan color, rather than purple to yellow, in the presence of carbon dioxide.
  • a purple-to-tan color change rather than a purple-to-yellow color change is that the contrast ratio between purple and tan is particularly advantageous, allowing a healthcare worker to distinguish finer gradations of carbon dioxide levels.
  • the purple-to-tan color change is also helpful for people with color blindness, which most often impairs acuity in the green-yellow-red portion of the spectrum.
  • Indicator Color in all Tables and Figures where used was determined using a Hunterlab LS6000 colorimeter and gas concentrations of 0.03, 1 and 2% CO 2 (balance N 2 ).
  • the CR color scale was devised so that a value of 0 corresponds to a bright yellow color while a value of 100 corresponds to deep purple. For the data shown in Figures 5 and 6, the highest value of the bar is the CR value measured when the indicator strip was exposed to 0.03% CO 2 (e.g. "room air").
  • the lowest value of the bar is the CR value measured when the indicator strip was exposed to 2% CO 2 .
  • the total length of the bar is therefore indicative of the extent of color change that is seen when the CO 2 concentration is transitioned between 0.03% and 2.0%.
  • the shading of the bar was chosen using a CR value of 40 as the visual transition point between yellow and purple.
  • Figure 6A shows the rate of color change sensitivity to CO 2 in cellulose substrate detector systems under accelerated aging conditions.
  • the data in Figure 6A was collected by exposing a cellulose detector system in a sealed package in the presence of desiccant to 60 0 C temperatures. The elevated temperature was used to allow the test to be performed more quickly. Elevated temperature increases the rate of cresol red reaction with substrate 12.
  • Figure 6A shows, after 3 days of the accelerated ageing experiment, the cellulose-based carbon dioxide detectors have little sensitivity to the presence of carbon dioxide.
  • Figure 6B shows a similar test conducted with carbon dioxide detector system with a borosilicate and acrylic substrate. Even after 7 days of exposure to accelerated aging conditions, the sensitivity of the color indicator to CO 2 was quite high. Results of the experiments shown in Figure 6 are presented in Table 2.
  • a borosilicate based detector may be provided in packaging without desiccant.
  • This packaging may include gas-impermeable metallic foil.
  • the device may also be sealed under an atmosphere substantially devoid of carbon dioxide.
  • the device may be sealed in packaging currently in use for carbon dioxide detector systems but without the need for desiccant.
  • Cellulose filter paper is strongly hydrophilic so that in warm, humid air, water is rapidly absorbed into the substrate. This reduces the responsivity of an indicator to changes in carbon dioxide concentration.
  • the inhalation responsivity of a cellulose-based detector after exposure to humid air for certain time periods as compared to a detector of the present disclosure having a borosilicate and acrylic substrate is shown in Figure 7. While both detectors show clinically useful responsiveness, The cellulose-based detector takes 13 seconds longer to respond to inhalation after 5 minutes of exposure to humid air. Data showing this difference is presented in Figure 7. Response times of greater than 40 seconds were not timed for their full duration.
  • a cellulose-based detector as compared to a detector of the current invention with borosilicate and acrylic substrate displays similar sensitivity to exhalation after exposure to humid air. This is in contrast to results achieved during inhalation described above. These levels of responsiveness are expected because the chemical reaction necessary for color change during exhalation is less sensitive to humidity. These results are also presented in Figure 7. Comparative data for both inhalation and exhalation is presented in Table 4. Table 4: Response Time of Carbon Dioxide Detectors after Exposure to Humid Air
  • detector system 20 may include carbon dioxide detector 10, housing 24, air intake 26, and color indicators 28.
  • Detector system 20 may be configured to fit into a further system, such as resuscitator 60.
  • the further system may supply air to detector system 20 for measurement.
  • the further system may be connected to the respiratory pathway of a patient.
  • Parts of detector system 20, such as housing 24 and/or air intake 26 may be made from a rigid material.
  • they may be made from a plastic, such as a clear colorless, transparent plastic.
  • housing 24 and/or air intake 26 may be made from polyethylene, polypropylene, an acrylic polymer such as PLEXIGLAS® polymer, polycarbonate, nylon, polysytrene, and styrene-acrylonitrile copolymer. At least a portion of housing 24 may be clear so as to allow viewing of carbon dioxide detector 10.
  • Air intake 26 may also serve to couple detector system 20 with any further system. It may be releasably secured to housing 24, such as by a threaded engagement, or it may form an integral unit with housing 24. Air intake 26 may also have a threaded engagement, tab or grooves, or other features to allow it to be releasably secured to any further system. For example, a pressure fit is used to couple the detector system to the manual resuscitator in the current INdGO/IndCAPTM products (Nellcor, Tyco Healthcare, California).
  • Color indicators 28 may approximately match the color of indicator solution 14 in the presence of difference levels of carbon dioxide.
  • Color indicators 28 may also include written or other visual information to allow a user to determine what carbon dioxide concentrations are indicated by various colors.
  • region A may show one or various shades that correlate with a low carbon dioxide concentration, such as below approximately 0.5% or between approximately 0.03% and 0.5%.
  • region A may contain shades of purple.
  • Region C may show one or various shades that correlate with a high carbon dioxide concentration typical of respired air, such as above approximately 2% or between 2% and 5%.
  • region C may contain shades of yellow.
  • Optional region B may indicate carbon dioxide concentrations above that of normal or esophageal air, but below that corresponding with normal respiration.
  • region B may indicate carbon dioxide concentrations common in respired air of a patient suffering from perfusion failure.
  • Region B may show one or various shades that correlate with carbon dioxide concentrations of between approximately 0.5% and 2%.
  • region B may contain shades of grayish purple.
  • detector system 40 may include carbon dioxide detector 10, housing 44, air intake 46, and color indicators 28.
  • Housing 44 and air intake 46 may be similar to housing 24 and air intake 26 in composition and function. However, they may be of a different shape to allow use with other systems.
  • resuscitator 60 may include carbon dioxide detector system 40, which attaches to resuscitator housing 56. Carbon dioxide detector system 20 may also be used with resuscitator 60 (not shown). Resuscitator 60 may also have endotracheal tube attachment 50, swivel joint 52, and bag 54. Resuscitator 60 may be formed in any manner known to the art. In particular it may be formed in the manner of an INdGOTM disposable manual resuscitator (Nellcor, Tyco Healthcare, California).
  • Detection may include in-stream detection, such as in the current EasyCapTM (Nellcor, Tyco Healthcare, California) system. It may also include "side-stream” detection, such as in the current INdCAPTM product (Nellcor, Tyco Healthcare, California). The detection system may be modified to facilitate either form of detection.
  • Carbon dioxide detector 10 may be prepared by forming substrate 12 then impregnating or coating it with indicator solution 14. Substrate 12 may then be dried to immobilize indicator solution 14 on it. Substrate 12 may then be incorporated into a detector system such as those shown in Figures 2 and 3. The detector system may then be packaged in protective packaging. It may also be incorporated in a further system, such as resuscitator 60, before packaging. During its formation and handling prior to packaging, carbon dioxide detector 10 may be kept in conditions to minimize or control chemical reactions that might negatively influence its reliability. For example, it may be kept in dry conditions after drying.
  • Carbon dioxide detectors of the present disclosure may require less stringent pre-packaging conditions than current cellulose filter paper detectors because of improvements in resistance to negative effects of humidity and room air. Carbon dioxide detectors, detection systems, of further systems such as resuscitators may be created in a sterile or clean environment or later sterilized. [0086] Carbon dioxide detector 10 may be used by providing air to it. The air then infiltrates substrate 12 and any carbon dioxide in the air reacts with indicator solution 14. This may produce a color change in the indicator. Carbon dioxide detector 10 may specifically be used to detect air from an endotracheal tube. Such systems and method are discussed in the U.S.
  • Carbon dioxide detector 10 may be used to monitor any patient benefiting from an endotracheal tube or other endotracheal system, e.g. a resuscitator fitted with a mask. More specifically, if may be used to monitor a human patient, such as a trauma victim, an anesthetized patient, a cardiac arrest victim, a patient suffering from airway obstruction, or a patient suffering from respiratory failure.
  • a human patient such as a trauma victim, an anesthetized patient, a cardiac arrest victim, a patient suffering from airway obstruction, or a patient suffering from respiratory failure.
  • the substrate may be formed in a variety of ways; various indicators, alkali sources and other components may be used in the indicator solution; the indicator solution may be placed on the substrate in a variety of ways; multiple indicators may be used to detect narrower ranges of carbon dioxide concentration; and the system may take a variety of shapes.

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Abstract

L'invention concerne un détecteur de dioxyde de carbone comprenant un substrat de borosilicate. Ce détecteur peut également comprendre une solution indicatrice de dioxyde de carbone disposée sur le substrat de borosilicate. Ce détecteur de dioxyde de carbone peut former une partie d'un système de détection de dioxyde de carbone comprenant également une entrée d'air raccordée de manière fonctionnelle au boîtier pour permettre à l'air de parvenir jusqu'au détecteur de dioxyde de carbone. Le détecteur de dioxyde de carbone peut comprendre un substrat de borosilicate et une solution indicatrice réagissant au dioxyde de carbone, disposée sur le substrat de borosilicate. Le détecteur peut faire partie d'un autre système tel qu'un système de réanimation. On peut produire ce détecteur en humidifiant un substrat de borosilicate avec une solution indicatrice réagissant au dioxyde de carbone, puis en séchant la solution indicatrice pour l'immobiliser et former un détecteur de dioxyde de carbone sec. Ce détecteur peut être utilisé pour détecter la concentration de dioxyde de carbone dans un échantillon d'air, par exposition du détecteur à l'échantillon.
EP07861362A 2006-09-25 2007-09-24 Détecteur de dioxyde de carbone comprenant substrat de borosilicate Withdrawn EP2067030A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US11/526,417 US8449834B2 (en) 2006-09-25 2006-09-25 Carbon dioxide detector having borosilicate substrate
US11/526,393 US8431087B2 (en) 2006-09-25 2006-09-25 Carbon dioxide detector having borosilicate substrate
US11/526,834 US8431088B2 (en) 2006-09-25 2006-09-25 Carbon dioxide detector having borosilicate substrate
US11/526,369 US8420405B2 (en) 2006-09-25 2006-09-25 Carbon dioxide detector having borosilicate substrate
PCT/US2007/020616 WO2008039424A2 (fr) 2006-09-25 2007-09-24 Détecteur de dioxyde de carbone comprenant substrat de borosilicate

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EP2067030A2 true EP2067030A2 (fr) 2009-06-10

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US10175254B2 (en) 2013-07-16 2019-01-08 Palo Alto Health Sciences, Inc. Methods and systems for quantitative colorimetric capnometry
CN105675607A (zh) * 2016-04-22 2016-06-15 吉林农业大学 一种通过二氧化碳检测食品新鲜度的指示材料及制备方法
CN112957254A (zh) * 2021-02-04 2021-06-15 南京天华科技开发有限责任公司 二氧化碳指示剂、应用和方法

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US5005572A (en) * 1988-02-26 1991-04-09 Brigham & Women's Hospital CO2 indicator and the use thereof to evaluate placement of tracheal tubes
FR2650076B1 (fr) * 1989-07-20 1991-10-04 Commissariat Energie Atomique Capteur chimique actif a fibre optique et son procede de fabrication
EP0451719B1 (fr) * 1990-04-12 1996-12-27 Hitachi, Ltd. Dispositif de détermination d'au moins une composante gazeuse d'un échantillon gazeux ou liquide et procédé de détermination
CA2376699C (fr) * 1999-06-29 2004-09-21 Carrier Corporation Biocapteurs de surveillance de procedes de climatisation et de refrigeration
CN100340857C (zh) * 1999-12-15 2007-10-03 凸板印刷株式会社 二氧化碳气体检测用油墨组合物、和使用该组合物的二氧化碳指示器、以及配置了该指示器的包装体
GB0319743D0 (en) * 2003-08-22 2003-09-24 Smiths Group Plc Resuscitators, parts and assemblies

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Title
See references of WO2008039424A2 *

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WO2008039424A2 (fr) 2008-04-03
WO2008039423A2 (fr) 2008-04-03
WO2008039424A3 (fr) 2008-06-19
WO2008039423A3 (fr) 2008-06-19

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