Abstract
An oxygen mask that incorporates chemical carbon dioxide (EtCO2) detectors to allow for the monitoring of patient respiration/ventilation without the use of clinical signs or electronic computer technology by providing a visual indication (through color change of the EtCO2 detectors) of the presence or absence of carbon dioxide.
Claims
1. A face mask, comprising: a port configured to permit a flow of gas; a shell, configured to surround a mouth and nose of a human face; and a reversible colorimetric carbon dioxide indicator, configured to receive a flow of exhaled air from the human face and to colorimetrically distinguish between respiration-induced flow of carbon dioxide in the exhaled air, and a respiratory obstruction.
2. The face mask according to claim 1, wherein the port is configured to receive the flow of gas, further comprising a second port configured to permit flow of exhaled air from the human face out of the face mask.
3. The face mask according to claim 1, wherein the reversible colorimetric carbon dioxide indicator comprises a ring.
4. The face mask according to claim 1, wherein the reversible colorimetric carbon dioxide indicator comprises a coating on an inner surface of the face mask.
5. The face mask according to claim 1, wherein the reversible colorimetric carbon dioxide indicator is responsive to exhaled carbon dioxide over a range of inlet port flow of oxygen over a range of 0.5-15 liters per minute.
6. The face mask according to claim 1, wherein the shell comprises clear plastic, further comprising an adjustable nose piece; and an adjustable head strap.
7. The face mask according to claim 1, wherein the reversible colorimetric carbon dioxide indicator is attachable to the face mask.
8. The face mask according to claim 1, wherein the reversible colorimetric carbon dioxide indicator is removable from the face mask.
9. The face mask according to claim 1, further comprising an illuminator configured to illuminate the reversible colorimetric carbon dioxide indicator and to project colored light from the reversible colorimetric carbon dioxide indicator.
10. A method of assessing breathing through a face mask configured to surround a mouth and nose of a human face, comprising: receiving a flow of a breathable gas into an inlet port of the faced mask; receiving a flow of exhaled air from a patient wearing the face mark; and interacting the flow of exhaled air with a reversible colorimetric carbon dioxide indicator, to colorimetrically distinguish between respiration-induced flow of carbon dioxide in the exhaled air and a respiratory obstruction.
11. The method according to claim 10, wherein the reversible colorimetric carbon dioxide indicator comprises a non-planar structure.
12. The method according to claim 10, wherein the reversible colorimetric carbon dioxide indicator comprises a ring.
13. The method according to claim 10, wherein the reversible colorimetric carbon dioxide indicator comprises a coating on an inner surface of the face mask.
14. The method according to claim 10, wherein the reversible colorimetric carbon dioxide indicator is responsive to exhaled carbon dioxide over a range of inlet port flow of oxygen over a range of 0.5-15 liters per minute.
15. The method according to claim 10, wherein the shell comprises clear plastic, further comprising an adjustable nose piece; and an adjustable head strap.
16. The method according to claim 10, further comprising attaching the reversible colorimetric carbon dioxide indicator to the face mask.
17. The method according to claim 10, further comprising removing the reversible colorimetric carbon dioxide indicator from the face mask.
18. The method according to claim 10, further comprising illuminating the reversible colorimetric carbon dioxide indicator, and projecting colored light from the reversible colorimetric carbon dioxide indicator.
19. A face mask, comprising: an inlet port configured to receive an inflow of gas through an inlet check valve; a shell, configured to surround a mouth and nose of a human face, the shell having a plurality of sealed sampling ports; an outlet port configured to permit flow of exhaled air from the human face out of the face mask; and a reversible colorimetric carbon dioxide indicator, configured to pierce a respective sealed sampling port, and through the pierced sampling port, receive a flow of exhaled air from the human face and to colorimetrically distinguish between respiration-induced flow of carbon dioxide in the exhaled air, and a respiratory obstruction.
20. The face mark according to claim 19, wherein the reversible colorimetric carbon dioxide indicator is responsive to exhaled carbon dioxide over a range of inlet port flow of oxygen over a range of 0.5-15 liters per minute.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0070] FIG. 1 shows a front view of a first embodiment of the invention.
[0071] FIG. 2 shows a side perspective exploded view of the first embodiment of the invention.
[0072] FIG. 3 shows a side perspective exploded view of a second embodiment of the invention.
[0073] FIG. 4 shows a front view of a third embodiment of the invention.
[0074] FIG. 5 shows a side perspective exploded view of the third embodiment of the invention.
[0075] FIG. 6 shows front view of a modification of FIG. 4 having a port above the nose.
[0076] FIG. 7 shows side perspective exploded view of a modification of FIG. 5 having a port above the nose.
[0077] FIG. 8 shows a front view of a fourth embodiment of the invention.
[0078] FIG. 9 shows a front exploded view of the fourth embodiment of the invention.
[0079] FIG. 10 shows a side perspective view of the fourth embodiment of the invention.
[0080] FIG. 11 shows a front view of a fifth embodiment of the invention.
[0081] FIG. 12 shows a side perspective view of the fifth embodiment of the invention.
[0082] FIG. 13 shows a side perspective view of a sixth embodiment of the invention.
[0083] FIG. 14 shows a rear perspective exploded view of the sixth embodiment of the invention.
[0084] FIG. 15 shows a rear view of a seventh embodiment of the invention.
[0085] FIG. 16 shows a front view of a modification of FIG. 15 having a port located above the nose.
[0086] FIG. 17 shows a side perspective exploded view of a modification of FIG. 13 having a port located above the nose.
[0087] FIG. 18 shows a side perspective exploded view of the seventh embodiment of the invention.
[0088] FIG. 19 shows a rear perspective exploded view of the seventh embodiment of the invention.
[0089] FIG. 20 shows a rear view of the seventh embodiment of the invention.
[0090] FIG. 21 shows a rear perspective exploded view of a eighth embodiment of the invention.
[0091] FIG. 22 shows a side perspective exploded view of the eighth embodiment of the invention.
[0092] FIG. 23 shows a front view of the eighth embodiment of the invention.
[0093] FIG. 24 shows a schematic view of a rectangular colorimetric indicator.
[0094] FIG. 25 shows a schematic view of a circular colorimetric indicator.
[0095] FIG. 26 shows a prior art Nellcor EZCap colorimetric indicator.
[0096] FIG. 27 shows a capnogram.
DETAILED DESCRIPTION OF THE INVENTION
[0097] A preferred embodiment of the invention provides an oxygen mask with incorporated carbon dioxide indicators. Carbon dioxide, which is a normal component of exhaled gas, produces a changed visual display showing its presence via color change. An observer may then observe an alternating color change during inspiration and expiration (i.e., the presence or absence of carbon dioxide) due to the pH changes of the detecting material incorporated in the mask when mixed with carbon dioxide.
[0098] FIGS. 1-12 show a so-called simple facemask design, which does not seal around the edge.
[0099] In a facemask, oxygen is supplied through a hose adapter 18, which connects to inlet 19 below the nose portion of the mask 10. The mask 10 and its major components are formed of a transparent flexible plastic, such as polyvinyl chloride. The inlet 19 is located midline, below the nose of the mask 10 and above the lower border of the edge 14 of the mask 10.
[0100] The oxygen is inhaled by the individual during inspiration. The pH indicator of the carbon dioxide detector 30 is placed near fenestrated ports 20 for passing exhaled breath out of the mask 10. The fenestrated ports 20 can be placed on one, both sides, front, or the dome of the mask, for example.
[0101] The mask 10 is held to the patient's face by a set of adjustable elastic straps (not shown) affixed to strap holders 14, with female luer lock connector 40 and male cap 42 on the body of the mask 10. The nose bridge of the mask 10 is adjustable to fit by a plastically-deformable element 12 which is, for example, a soft aluminum sheet.
[0102] As shown in FIGS. 1 and 2 of the first embodiment of the invention, the carbon dioxide detector 30 is provided as a bulb in front of the nose, which is visible >180 degrees in front of the patient. The inside of the bulb 30 is coated with indicator dye. The fenestrated ports 20 are located such that an exhale flow pattern distributes gas within the bulb 30, while between breaths the bulb 30 is flushed with clean oxygen from the hose adapter 18.
[0103] In a second embodiment shown in FIG. 3, is similar to the first embodiment, but the mask 10 has a series of ports 22, which are sealed with a membrane, in various portions of the mask 10. A colorimetric capnometer, such as the Nellcor EZCap™ II, shown representatively in FIG. 22, may be inserted into one or more ports 22, piercing the membrane to allow a flow path from inside the mask to the outside. This allows a caregiver to select the desired location or locations for the indicator based on the orientation of the patient. The orientation of the colorimetric capnometer may be adjusted for visibility.
[0104] As shown in FIGS. 4 and 5 of the third embodiment of the invention, the carbon dioxide detector 36 medium is a film or paper which is held behind a grill 32, in front of a shell 34. The fenestrated ports 20 are located such that an exhale flow pattern distributes gas around the carbon dioxide detector 36 medium, while between breaths the carbon dioxide detector 36 medium is flushed with clean oxygen from the hose adapter 18.
[0105] FIGS. 6 and 7 show modifications of FIGS. 4 and 5, respectively, having a port 40 above the nose. The port 40 may provide a vent for exhaled air, an interface to a sampling tube, or a separate colorimetric indicator (not shown). When not in use, a cap 42 blocks gas flow.
[0106] As shown in FIGS. 8, 9 and 10 of the fourth embodiment of the invention, a pair of indicators 36 are provided on the left and right sides of the mask 10, behind grills 32 and in front of shells 34. The fenestrated ports 20 are located surrounding the carbon dioxide detector 36 medium, and an exhale flow pattern distributes gas around the carbon dioxide detector 36 medium venting through the fenestrated ports 20, while between breaths the carbon dioxide detector 36 medium is flushed with clean oxygen from the hose adapter 18.
[0107] FIGS. 11 and 12 of the fifth embodiment of the invention has a centrally-located the carbon dioxide detector 36 medium indicator, behind grill 32 and in front of shell 34. The exhale flow path (not shown) is through ports below the nostrils. Oxygen is suppled through a hose adapter 18, which in this case splits into two hoses feeding the left and rights sides of the mask. This configuration supports high flow rates, and the dual tubes are more flexible than a single tune with the same cross section area and flow capacity. In a variant of the fourth embodiment, the hose adapter has dual lumens, and one of the tubes leading to the mask is used as a sampling port for exhaled gas. Typically, only a small portion of the exhaled gas passes through the sampling port, and the majority is released to the atmosphere.
[0108] FIGS. 13-20 show a bag valve mask (positive pressure mask) that has a seal around the face.
[0109] FIGS. 13, 14 and 15 of the sixth embodiment of the invention show a mask 100 in which oxygen or air is fed in front of the nose through port 104. The mask has a gas-filled edge 102 that provides a compliant seal against the face of the wearer. The indicator 110 is configured as a ring around the inlet port 104, visible through the mask from 180 degrees. This design is suitable for administering cardiopulmonary resuscitation (CPR), with the caregiver isolated from the patient. Note that the carbon dioxide detector medium indicator 120 will not measure the patient's carbon dioxide exhalation accurately during CPR, and the indicator is provided for an initial assessment of patient breathing before commencement of CPR, and perhaps periodically after commencement. No exhale ports need be provided because the mask is readily removed from the face between breaths.
[0110] FIGS. 16 and 17 show a modification of FIGS. 15 and 13, respectively, having a port 140 located above the nose. The port 140 may provide a vent for exhaled air, an interface to a sampling tube, or a separate colorimetric indicator (not shown). When not in use, a cap 142 blocks gas flow.
[0111] FIGS. 18, 19 and 20 of the seventh embodiment of the invention show a mask 100 in which oxygen or air is fed in front of the nose through port 104. The mask has a gas-filled edge 102 that provides a compliant seal against the face of the wearer. The indicator 120 is configured as a disk around the inlet port 104, visible through the mask from front and sides. In this case, the indicator 120 disk may be porous, and allow air flow through it during use, or mounted as a baffle for air flow around the disk to ensure contact of the flowing air with the surfaces of the disk. As with the sixth embodiment, the design of the seventh embodiment is suitable for administering cardiopulmonary resuscitation (CPR), with the caregiver isolated from the patient, in this case with a physical barrier than can serve as a filter. The carbon dioxide detector medium indicator 120 can measure the caregiver's exhaled carbon dioxide during CPR, and help assure breaths provided to the patient are not stale.
[0112] FIGS. 21-23 show a barrier mask to permit a caregiver to administer rescue breaths to a patient without physical contact. A caregiver breathes through a tube which has a one-way inlet check valve to prevent backflow from the patient to the caregiver. An outlet check valve in the mask permits inhalation by the patient when the mask is sealed against the face of the patient.
[0113] FIGS. 21, 22 and 23 of the eighth embodiment are also similar to the sixth embodiment, employing a mask 100 in which oxygen or air is fed in front of the nose through port 104. The mask has a gas-filled edge 102 that provides a compliant seal against the face of the wearer. The indicator 110 is configured as a ring around the inlet port 104, visible through the mask from 180 degrees. This design is suitable for administering cardiopulmonary resuscitation (CPR), with the caregiver isolated from the patient. A valved inhale port 106 is provided with an elastomeric sealing disk 108 mounted on a central pin. In this configuration, if a low oxygen flow rate is provided through the port 104, any excess air is drawn through the valved inhale port 106. For example, if a patient is provided with 2 liters per minute of oxygen, at least 50% of the inhaled gas will bypass through the valved inhale port 106. During exhale, the patient's breath will pass near the ring indicator 110, and either back through the inlet port 104 if possible, or around the edge 102 of the mask 100.
[0114] FIGS. 24 and 25 show rectangular 150 and circular 160 colorimetric indicators, with surrounding regions 152, 154, 156, 158, 162, 164, 166, 186 on which accurate colors are printed showing the color of the indicator under respective conditions of CO.sub.2, e.g., 0.03, 0.5, 2.0, and 5.
[0115] FIG. 26 shows a perspective view of a prior art Nellcor EZCap™ II colorimetric indicator capnometer. Such devices are known for use with endotracheal tubes, and have not been integrated with or disposed on respirator masks.
[0116] FIG. 27 shows a normal capnogram, showing changes of carbon dioxide in exhaled breath over time. Clean air has a trace amount of carbon dioxide, while the end tidal CO.sub.2 is about 25-45 mmHg (4.6%-6%).
[0117] The carbon dioxide detectors may use various chemistries, e.g., metacresol purple, to provide a visual color change (purple in air, yellow in 4%+CO.sub.2) that is rapid and reversible, and changes in the presence or absence of gaseous carbon dioxide. The detectors may be encased in a housing that allows for optimal visualization from a wide range of vantage points, regardless of the orientation of the mask to the observer. The detector housings isolate the chemical agents from the patient and room environment. These housings allow for easy attachment to and removal from the masks various attachment points, as well as an optimal air flow to allow for the largest detection of carbon dioxide and therefore largest color change in the respiratory cycle of the patient.
[0118] The invention alleviates the need for subjective or unreliable measures of breathing, such as chest movement or the expensive, computerized, battery operated capnometers. The colorimetric indicator is preferably single-use, and may produce valid results for a duration.
[0119] It should be understood that the preferred embodiments and examples described herein are for illustrative purposes only and are not to be construed as limiting the scope of the present invention, which is properly delineated only in the appended claims.
