CATHETER INFLATABLE CUFF PRESSURE STABILIZER
20210338955 · 2021-11-04
Inventors
Cpc classification
A61M16/044
HUMAN NECESSITIES
A61M2205/3341
HUMAN NECESSITIES
A61M16/0003
HUMAN NECESSITIES
A61M2025/1047
HUMAN NECESSITIES
G01L7/18
PHYSICS
A61M25/10187
HUMAN NECESSITIES
A61M25/1018
HUMAN NECESSITIES
A61M2025/1052
HUMAN NECESSITIES
International classification
A61M16/00
HUMAN NECESSITIES
Abstract
A cuff pressure stabilizer (100, 200, 300, 500, 600, 800) is provided that includes an inflation lumen proximal port connector (134), which is shaped to form an air-tight seal with an inflation lumen proximal port (15) of a catheter (10) additionally having an inflatable cuff (11) and an inflation lumen (13); a fluid reservoir (120, 524, 624); a liquid column container (118, 518, 618), which is (a) open to the atmosphere (99) at at least one site along the liquid column container, (b) in fluid communication with the fluid reservoir (120, 524, 624), and (c) in communication with the inflation lumen proximal port connector (134) via the fluid reservoir (120, 524, 624); and a liquid (121), which is contained (a) in the fluid reservoir (120, 524, 624), (b) in the liquid column container (118, 518, 618), or (c) partially in the fluid reservoir (120, 524, 624) and partially in the liquid column container (118, 518, 618), and which has a density of between 1.5 and 5 g/cm3 at 4 degrees Celsius at 1 atm.
Claims
1-52. (canceled)
53. Apparatus for use in contact with the atmosphere of the Earth and for use with a gas and a catheter having an inflatable cuff, an inflation lumen, and an inflation lumen proximal port, the apparatus comprising a cuff pressure stabilizer, which is configured to provide automatic pressure regulation of the inflatable cuff of the catheter, and which comprises: an inflation lumen proximal port connector, which is configured to form an air-tight seal with the inflation lumen proximal port of catheter, so as to assume a connected configuration; a gas inlet, which is in fluid communication with the inflation lumen proximal port connector; and a gas container, which (a) is in fluid communication with the inflation lumen proximal port connector via the gas inlet, (b) contains some of the gas, (c) comprises (i) at least one wall that comprises a volume-compensation movable wall, which is in pressure communication with the atmosphere on the other side of the volume-compensation movable wall, wherein the volume-compensation movable wall comprises a flexible elastic membrane, and (ii) a buffer chamber, which is shaped so as to define a chamber inlet port that is in fluid communication with the inflation lumen proximal port connector via the gas inlet, wherein the cuff pressure stabilizer is configured such that when the inflation lumen proximal port connector is in the connected configuration, a combined air-flow resistance between an interior of the inflatable cuff and the gas container is such that a transient pressure difference of 5 cm H2O between the interior of inflatable cuff and the gas container results in gas flow from the interior of the inflatable cuff to the gas container at a slow rate of less than 0.1 cc per second that delays a response of the automatic pressure regulation of the cuff pressure stabilizer.
54. The apparatus according to claim 53, wherein at least one wall of the buffer chamber comprises the volume-compensation movable wall.
55. The apparatus according to claim 54, wherein the buffer chamber is configured such that a volume of the buffer chamber increases by at least 1 cc when a pressure of the gas in the buffer chamber increases from 25 cm H2O to 30 cm H2O.
56. The apparatus according to claim 55, wherein the buffer chamber is configured such that the volume of the buffer chamber increases by at least 2 cc when the pressure of the gas in the buffer chamber increases from 25 cm H2O to 30 cm H2O.
57. The apparatus according to claim 54, wherein the buffer chamber is configured such that a volume of buffer chamber increases by no more than 5 cc when a pressure of the gas in the buffer chamber increases from 25 cm H2O to 30 cm H2O.
58. The apparatus according to claim 53, wherein the cuff pressure stabilizer further comprises a buffer chamber casing shaped so as to define an enclosed volume-compensation movable wall expansion space into which the volume-compensation movable wall can expand.
59. The apparatus according to claim 58, wherein the buffer chamber casing is shaped so as to define a buffer chamber air environment port between the enclosed volume-compensation movable wall expansion space and the atmosphere.
60. The apparatus according to claim 53, wherein the cuff pressure stabilizer is configured such that when the inflation lumen proximal port connector is in the connected configuration, the transient pressure difference of 5 cm H2O between the interior of the inflatable cuff and the gas container results in the gas flow at a slow rate of less than 0.05 cc per second.
61. The apparatus according to claim 60, wherein the cuff pressure stabilizer is configured such that when the inflation lumen proximal port connector is in the connected configuration, the transient pressure difference of 5 cm H2O between the interior of the inflatable cuff and the gas container results in the gas flow at a slow rate of less than 0.02 cc per second.
62. The apparatus according to claim 61, wherein the cuff pressure stabilizer is configured such that when the inflation lumen proximal port connector is in the connected configuration, the transient pressure difference of 5 cm H2O between the interior of the inflatable cuff and the gas container results in the gas flow at a slow rate of less than 0.01 cc per second.
63. The apparatus according to claim 53, wherein the cuff pressure stabilizer further comprises an indicator module which continuously displays the pressure in the inflatable cuff.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF APPLICATIONS
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[0467] Tracheal ventilation tube 10 comprises an inflatable cuff 11, an inflation lumen 13, and an inflation lumen proximal port 15. Inflatable cuff 11 may comprise, for example, a balloon, and is typically mounted on tracheal ventilation tube 10 near a distal end of the tracheal ventilation tube, e.g., within 3 cm, such as within 1 cm, of the distal end. Inflatable cuff 11 typically comprises a nearly non-compliant material. A “balloon,” as used in the present application, including the claims, is an inflatable flexible bag, having any level of elasticity, including nearly non-elastic. Typically, inflatable cuff 11 has a volume of around 10 cc. Tracheal ventilation tube 10 typically further comprises a cuff inflation lumen distal port 12, a tracheal ventilation tube ventilation port 16, a tracheal ventilation tube ventilation lumen 17, and a tracheal ventilation tube ventilator connection 19. For some applications, tracheal ventilation tube 10 further comprises an inflating tube 14, which couples inflation lumen 13 in fluid communication with inflation lumen proximal port 15. Tracheal ventilation tube 10 is schematically shown inserted into a trachea 18. Inflatable cuff 11 is inflatable into sealing contact with the inner surface of trachea 18. As used in the present application, including in the claims, a “tracheal ventilation tube” comprises an endotracheal tube (ETT) or a tracheostomy tube.
[0468] Cuff pressure stabilizer 100 comprises: [0469] a casing 110; [0470] an inflation lumen proximal port connector 134, which is shaped to form an air-tight seal with inflation lumen proximal port 15 of tracheal ventilation tube 10; [0471] a gas inlet 141, which is in fluid communication with inflation lumen proximal port connector 134; [0472] a fluid reservoir 120, which typically has a volume of at least 2 cc (such as at least 3 cc, e.g., at least 4 cc), and optionally has a volume of less than 5 cc, and which contains some of the gas; [0473] a liquid column container 118, which is in fluid communication with gas inlet 141 via fluid reservoir 120; and [0474] a liquid 121, which is contained (a) in fluid reservoir 120, (b) in liquid column container 118, or (c) partially in fluid reservoir 120 and partially in liquid column container 118.
[0475] As can be seen, the gas partially fills fluid reservoir 120. When the system is in equilibrium, the pressure of the gas in fluid reservoir 120 equals the pressure of the gas in inflatable cuff 11. For some applications, inflation lumen proximal port connector 134 comprises a male conical fitting with a taper. For some applications, the taper is at least a 5% taper. For some applications, the taper is a 6% taper, and the male conical fitting with the 6% taper complies with International Standard ISO 594-1:1986, which is the standard for connections to conventional inflation lumen proximal ports of tracheal ventilation tubes. Typically, gas inlet 141 has a large cross-sectional area, such as at least 9 mm2, so that any droplets of liquid 121 that should happen to form will not clog the gas inlet.
[0476] Cuff pressure stabilizer 100 has a plurality of pressure indicia markings 126 distributed along liquid column container 118 for measuring a height of liquid 121 in liquid column container 118. Typically, casing 110 has pressure indicia markings 126, as shown in the figures, in which case pressure indicia markings 126 are distributed along liquid column container 118 by being distributed alongside liquid column container 118. Alternatively, for some applications, liquid column container 118 has pressure indicia markings 126 therealong. Liquid column container 118 is used in an aligned orientation (hereinbelow, the “aligned orientation”) in which pressure indicia markings 126 reflect, to within 1 cm H2O (i.e., with no error or an error of no more than 1 cm H2O), pressure of the gas in fluid reservoir 120 at least in a relevant pressure range 127 of 23-27 cm H2O, such as a range of 22-28 cm H2O, e.g., a range of 20-30 cm H2O, as marked numerically in the figures. The full marked scale 125 range typically extends both above and below the range of 20-30 cm H2O. The pressure is read by comparing a level 129 of fluid in liquid column container 118 with pressure indicia markings 126, as is known in the manometer art.
[0477] Typically, pressure indicia markings 126 reflect the height of liquid 121 in liquid column container 118 relative to the height of liquid 121 in fluid reservoir 120, as is known in the manometer art (as the liquid surface ascends in liquid column container 118, the liquid surface descends in fluid reservoir 120, though typically not by the same changes in heights). Therefore, the spacing of pressure indicia markings 126 depends in part on the shape and volume of fluid reservoir 120. For example, the spacing of pressure indicia markings 126 between 25 and 26 cm H2O may be different from the spacing of pressure indicia markings 126 between 26 and 27 cm H2O. In addition, for example, the wider the fluid reservoir, the greater the spacing of pressure indicia markings 126. For some applications, pressure indicia markings 126 are distributed evenly throughout at least relevant pressure range 127.
[0478] Typically, for applications in which liquid 121 comprises water, pressure indicia markings 126 are spaced at close to 1-cm intervals. For applications in which liquid 121 comprises a liquid with a higher or lower density than that of water, pressure indicia markings 126 are not spaced at 1-cm intervals, such as described hereinbelow. Optionally, liquid 121 comprises a dye to increase the visibility of the liquid for making the pressure measurements.
[0479] Typically, liquid column container 118 is configured to automatically assume the aligned orientation when cuff pressure stabilizer 100 is hung from or otherwise attached to a conventional IV pole, hospital wall, or other surface or object. For example, cuff pressure stabilizer 100 may comprise a coupling element that is configured to automatically orient liquid column container 118 in the aligned orientation. The coupling element may comprise a hook or a loop 128 that is hangable from a conventional hook of a conventional IV pole, similar to the standard hook of IV bags. Alternatively or additionally, the coupling element may comprise a squeezing coupler (e.g., a gripper or a clamp) that is coupleable to a vertical pole (e.g., a vertical IV pole) or a horizontal pole (e.g., a horizontal portion of one of the hooks of the IV pole), or another connector that is configured to be attached to a vertical surface, such as a hospital wall.
[0480] For some applications, when liquid column container 118 is oriented in the aligned orientation, liquid column container 118 has an inner cross-sectional area, measured in a horizontal plane 135, of at least 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2) at a plurality of (such as at most or all) axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at a respective plurality of pressures in relevant pressure range 127. Typically, the inner cross-sectional area, measured in horizontal plane 135, is less than 2 cm2 at a plurality of (such as at most or all) axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at a respective plurality of pressures in relevant pressure range 127, when liquid column container 118 is oriented in the aligned orientation.
[0481] As a result of this relatively large cross-sectional area, cuff pressure stabilizer 100 regulates (i.e., reduces fluctuations) the pressure of the gas in fluid reservoir 120 at least for changes of gas volume in the range of 0-2 cc, and thus at gas inlet 141 and in inflatable cuff 11, in addition to measuring the pressure. In contrast, conventional manometers only measure the pressure, without substantially affecting the pressure, as it is ideally and commonly the goal of measurement devices to not affect the measured target. For a given cuff of initial gas volume V, as the squeezing of inflatable cuff 11 by trachea 18 increases such that the available gas volume decreases, the volume of the gas in inflatable cuff 11 decreases by some fraction equal to the change in V divided by V because the cuff is nearly non-compliant. For endotracheal tubes without external regulation, this decrease in volume of the inflatable cuff results in an increase in pressure of the gas within the system, including within the inflatable cuff, since the gas contained in the cuff has no significant external volume to move into, in accordance with the ideal gas law; the opposite occurs when the level of squeezing on the cuff by the trachea decreases.
[0482] In experiments conducted by the inventors, the inventors found that, for real endotracheal tube cuff balloons of volumes around 10 cc, each 0.1 cc decrease in volume in the inflatable cuff resulted in about a 1 cm H2O increase in pressure in the system and the cuff, and each 0.1 cc increase in volume in the inflatable cuff resulted in about a 1 cm H2O decrease in pressure in the system and the cuff. This is a surprising significant departure from the ideal non-compliant gas law calculation which would predict a 0.01 cc volume change per 1 cm H2O pressure change. The inventors thus concluded that real endotracheal tube cuff balloons are in fact semi-compliant. Therefore, the mitigation volumes should be calculated based on the experimental finding. In clinical practice, the pressure in ETT inflatable cuffs generally varies +/−10 cm H2O from the typically target pressure of 25 cm H2O, i.e., varies between 15 and 35 cm H2O. Based on the above-mentioned experimental data, the inventors appreciated that the volume in ETT inflatable cuffs generally varies by +/−1 cc (+/−10 cm H2O times 0.1 cc/cm H2O), i.e., a total range of 2 cc, and, among a broader spectrum of patients, the volume of ETT inflatable cuffs generally varies by +/−20 cm H2O from the typical target pressure of 25 cm H2O, i.e., a total range of at least 4 cc.
[0483] The inventors appreciated that to the extent that cuff pressure stabilizer 100 is able to offset the changes in volume in inflatable cuff 11, the pressure changes are also offset, thereby stabilizing the pressure in inflatable cuff 11. Cuff pressure stabilizer 100 is able to offset the changes in volume in inflatable cuff 11 because of the relatively large cross-sectional area of liquid column container 118 at relevant pressure range 127, e.g., 23-27 cm H2O.
[0484] For example, assume that (a) liquid 121 comprises water, (b) the cross-sectional area of liquid column container 118 at relevant pressure range 127 is 1 cm2, (c) pressure indicia markings 126 are spaced at 1-cm intervals, and (d) the initial pressure in inflatable cuff 11 is 25 cm H2O. A decrease in volume of inflatable cuff 11 of 1 cc (caused by increased squeezing by the trachea) would displace from the inflatable cuff the excess 1 cc of gas into fluid reservoir 120, and a corresponding additional 1 cc of water out of fluid reservoir 120 into liquid column container 118. This additional 1 cc of water would fill an additional 1 cc of fluid reservoir 120, raising level 129 of fluid by 1 cm, and thus the pressure in inflatable cuff 11 (as indicated by pressure indicia markings 126) by 1 cm H2O, from 25 cm H2O to 26 cm H2O.
[0485] For a real inflatable cuff having a volume of 10 cc without attachment of the regulation system, a decrease in volume of inflatable cuff 11 of 1 cc would have resulted in an increase of the cuff pressure gas by about 10 cm H2O, based on the inventors' experimental data, i.e., the integration of the pressure regulator with tracheal ventilation tube 10 results in a factor of 10 suppression of the pressure change, resulting in the pressure regulation described herein.
[0486] More generally, the change in pressure in inflatable cuff 11 within relevant pressure range 127, resulting from a change in volume of inflatable cuff 11, when liquid 121 does not necessarily comprise water, is expressed by the following Equation 1:
ΔP=(ΔV/A)*d
[0487] in which: [0488] ΔV is the change in volume in cc of inflatable cuff 11, [0489] d is the density of liquid 121 in g/cm3 at 4 degrees Celsius at 1 atm, [0490] ΔP is the change in pressure in cm H2O in inflatable cuff 11, and [0491] A is the average cross-sectional area in cm2 of liquid column container 118 along the axial portion of the liquid column container in which the change in liquid height occurs during the change in volume of the inflatable cuff.
[0492] As used in the present application, including in the claims, “horizontal” means horizontal with respect to the Earth, i.e., perpendicular to a vertical line 102 directed to the center of gravity of the Earth, e.g., as ascertained using a plumb-line.
[0493] For some applications, at the plurality of axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at the respective plurality of pressures in relevant pressure range 127, the inner cross-sectional area is at least 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2), when liquid column container 118 is oriented in the aligned orientation.
[0494] Typically, liquid column container 118 is wider (i.e., has a greater cross-sectional area) in (a) a relevant-range fluid compartment 123 that includes relevant pressure range 127 than in (b) a lower-range fluid compartment 122 that reflects pressures of the gas in fluid reservoir 120 of less than 20 cm H2O. In other words, when liquid column container 118 is oriented in the aligned orientation, an average inner cross-sectional area, measured in horizontal plane 135, at all axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at the respective plurality of pressures in relevant pressure range 127 is greater than the product of (a) a factor greater than one and (b) an average inner cross-sectional area of liquid column container 118, measured in horizontal plane 135, at all axial locations along liquid column container 118 corresponding to pressure of the gas in fluid reservoir 120 of less than 20 cm H2O. For some applications, the factor is 150%, such as 200%, 300%, 400%, or 500%. The narrower liquid column container 118 in lower-range fluid compartment 122 reduces the total required amount of liquid 121, which is useful in configurations in which liquid 121 comprises an expensive heavy liquid.
[0495] For some of these applications, when liquid column container 118 is oriented in the aligned orientation, the inner cross-sectional area at the plurality of axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at the respective plurality of pressures in relevant pressure range 127 equals at least 200% of an average inner cross-sectional area of liquid column container 118, measured in horizontal plane 135, at most or all axial locations along liquid column container 118 corresponding to a pressure of the gas in fluid reservoir 120 of between 5 and 15 cm H2O. For some applications, the average inner cross-sectional area is less than 0.16 cm2, such as less than 0.09 cm2, at most or all axial locations along liquid column container 118 corresponding to a pressure of the gas in fluid reservoir 120 of between 5 and 15 cm H2O, when liquid column container 118 is oriented in the aligned orientation.
[0496] For some applications, liquid column container 118 is wider (i.e., has a greater cross-sectional area) in (a) a buffer fluid compartment 124 that reflects pressures of the gas in fluid reservoir 120 of greater than 28 cm H2O, e.g., greater than 30 cm H2O that includes relevant pressure range 127 than in (b) relevant-range fluid compartment 123 that includes relevant pressure range 127. In other words, when liquid column container 118 is oriented in the aligned orientation, an average inner cross-sectional area at all axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at the respective plurality of pressures in the relevant range is less than the inner cross-sectional area of liquid column container 118, measured in horizontal plane 135, at at least one axial location along liquid column container 118 corresponding to a pressure of the gas in fluid reservoir 120 of between 28 cm and 35 cm H2O. The wider liquid column container 118 in buffer fluid compartment 124 substantially reduces increases in pressure if the pressure should exceed the lower end of the pressure range of buffer fluid compartment 124, because buffer fluid compartment 124 can hold a greater volume of liquid per unit of height than can relevant-range fluid compartment 123.
[0497] For some applications, liquid 121 has a density of between 0.8 and 12 g/cm3 at 4 degrees Celsius at 1 atm, and/or a density of between 0.8 and 12 g/cm3 at 20 degrees Celsius at 1 atm. Typically, the density (whether at 4 degrees or at 20 degrees) is between 1.5 and 5 g/cm3, such as between 2 and 4 g/cm3, e.g., between 2.5 and 3.5 g/cm3 (all of these values are more dense than water and less dense than mercury). For some applications, liquid 121 comprises a tungstate-based liquid, e.g., selected from the group consisting of: sodium polytungstate, sodium metatungstate, lithium polytungstate, and lithium metatungstate. Alternatively or additionally, liquid 121 may have any of the characteristics described hereinbelow with reference to
[0498] To the extent that the density d of liquid 121 is greater than that of water, i.e., greater than 1 g/cm3 at 4 degrees Celsius at 1 atm, a shorter liquid column container 118 can be used to measure and regulate pressures, and pressure indicia markings 126 are closer together. Assuming a container of uniform cross section and a liquid column of uniform cross section, it follows from Equation 1 (ΔP=(ΔV/A)*d) that, if using a liquid of density d compared with using water, the distance between pressure indicia markings 126 for indicating a 1 cm H2O change in pressure equals the quotient of (a) 1 cm divided by (b) the density of liquid 121 at 4 degrees Celsius at 1 atm. For some applications, a distance between a highest point 136 of liquid column container 118 and a lowest point 137 of fluid reservoir 120 is between 10 and 20 cm, when liquid column container 118 is oriented in an aligned orientation. The highest point is measured with respect to the center of gravity of the Earth.
[0499] For some applications, as shown in the figures and labeled in
[0500] Typically, liquid column container 118 is open to atmosphere 99 at at least one site 139 along liquid column container 118. Liquid column container 118 has first and second ends 143 and 144 at opposite ends of liquid column container 118. For some applications, liquid column container 118 is in fluid communication with fluid reservoir 120 via first end 143, the at least one site 139 is at second end 144, and liquid column container 118 is open to atmosphere 99 at second end 144. For some applications, liquid column container 118 defines an opening 142 having an area of between 0.09 and 1 mm2, and liquid column container 118 is open to atmosphere 99 via opening 142. For some applications, cuff pressure stabilizer 100 further comprises a sealing element 145 (e.g., a plug or screw-cap) that is removably disposed so as to seal opening 142 (shown removed in
[0501] For some applications, when liquid column container 118 is oriented in the aligned orientation, at least 2 cc, no more than 10 cc, and/or between 2 and 10 cc (e.g., between 2 and 8 cc, such as between 2 and 6 cc, e.g., between 2 and 4 cc) of liquid 121 are contained in fluid reservoir 120 at a lower height than first end 143 of liquid column container 118. For some applications, an upper surface area of liquid 121 in fluid reservoir 120 is at least 2 cm2, no more than 8 cm2, and/or between 2 and 8 cm2 (e.g., between 2 and 6 cm2, such as between 2 and 4 cm2), when (a) liquid column container 118 is oriented in the aligned orientation and (b) the pressure of the gas in fluid reservoir 120 is 25 cm H2O.
[0502] For some applications, cuff pressure stabilizer 100 further comprises: [0503] an inflation inlet port 130, which is coupleable with an external inflation source 20, such as a syringe; [0504] a first connector tube 133, which couples inflation lumen proximal port connector 134 in fluid communication with inflation inlet port 130; and [0505] a second connector tube 132, which couples gas inlet 141 in fluid communication with inflation inlet port 130, such that inflation lumen proximal port connector 134 is in fluid communication with gas inlet 141 via first connector tube 133 and second connector tube 132.
[0506] Typically, inflation inlet port 130 comprises a valve, such as a directional valve. Inflation inlet port 130 isolates the system such there is no exchange of gas (air) between inflatable cuff 11 and atmosphere 99 (ambient air) after initial inflation by external inflation source 20.
[0507] For some applications, cuff pressure stabilizer 100 further comprises an inlet junction 131, which comprises inflation inlet port 130, and which couples in fluid communication inflation inlet port 130, first connector tube 133, and second connector tube 132.
[0508] For some applications, when (a) inflation lumen proximal port connector 134 forms the air-tight seal with inflation lumen proximal port 15 of tracheal ventilation tube 10 and (b) a pressure of the gas of the gas in fluid reservoir 120 is 10 cm H2O, (i) a first combined air-flow resistance between inflation inlet port 130 and an interior of inflatable cuff 11 equals between 80% and 120% of (ii) a second combined air-flow resistance between inflation inlet port and fluid reservoir 120, such as between 90% and 110%, e.g., between 95% and 105%. Typically, in order to achieve these relative air-flow resistances, the relative lengths of first and second connector tubes 133 and 132 are set such that the resistance of second connector tube 132 equals the sum of the resistance of first connector tube 133 and a fixed constant resistance of all elements of tracheal ventilation tube 10 in the flow path. This approximately equal air-flow resistance prevents transient false pressure readings immediately following inflation or reinflation of inflatable cuff 11 via inflation inlet port 130, without being dependent on the technique of the healthcare worker. For example, if the resistance from inflation inlet port 130 were lower in second connector tube 132 (to cuff pressure stabilizer 100) than in first connector tube 133 (to inflatable cuff 11), during inflation initially a majority of the air would flow toward cuff pressure stabilizer 100. As a result, level 129 of fluid in liquid column container 118 would indicate a higher pressure than the true pressure of inflatable cuff 11. If external inflation source 20 were to be disconnected at this point in time, the pressure shown by liquid column container 118 would gradually decrease as pressure equilibrium between inflatable cuff 11 and fluid reservoir 120 is gradually reached.
[0509] For some applications, cuff pressure stabilizer 100 further comprises one or more connector tubes, which couple inflation lumen proximal port connector 134 in fluid communication with gas inlet 141. When inflation lumen proximal port connector 134 forms the air-tight seal with inflation lumen proximal port 15 of tracheal ventilation tube 10, a combined air-flow resistance between an interior of inflatable cuff 11 and fluid reservoir 120 is such that a transient pressure difference of 5 cm H2O between the interior of inflatable cuff 11 and fluid reservoir 120 results in less than a 0.1 cc per second, e.g., less than a 0.05, a 0.02, or a 0.01 cc per second, fluid flow from inflatable cuff 11 into fluid reservoir 120. The slow rate of flow delays the automatic pressure-regulation response from cuff pressure stabilizer 100. A too rapid pressure-regulation response might underinflate inflatable cuff 11 during transient, short-term increases in pressure in the inflatable cuff, such as during the positive pressure phase of the ventilation cycle when high-pressure ventilation (generally greater than 25 cm H2O) is applied to the patient, generally for only a few seconds, typically less than 3 seconds.
[0510] For patients ventilated at high peak inspiratory pressure (PIP), i.e., greater than 25 cm H2O and sometimes even up to 40 cm H2O, there is a need to both maintain the high ventilation pressure during the peak ventilation and to maintain on average the balloon pressure near 25 cm H2O. For these patients only, it is advantageous to limit the fluid flow between inflatable cuff 11 and fluid reservoir 120, as described immediately above, at the expense of increasing the pressure regulation response time of cuff pressure stabilizer 100.
[0511] Generally, high PIP is applied to less than 30% of patients. For the remaining 70% of patients there is no need for flow limitation. To the contrary, the longer response time due to flow limitation compromises the desired fast response to low cuff pressures. To best accommodate these differing patient needs, in some applications, cuff pressure stabilizer 100 comprises a switch that sets flow states of cuff pressure stabilizer 100, including (a) a flow-limiting state (e.g., via a flow-limiting channel, as described immediately above, and (b) a fast-flow state (e.g., via a fast-flow channel, which is sized so as to substantially not limit flow, e.g., such that a transient pressure difference of 5 cm H2O between the interior of inflatable cuff 11 and fluid reservoir 120 results in greater than a 0.02 cc per second, e.g., more than a 0.05 cc per second, fluid flow from inflatable cuff 11 into fluid reservoir 120). A healthcare worker selects which of these two channels to enable according to the individual patient's ventilation needs. In addition, the healthcare worker may select the fast-flow channel during inflation of inflatable cuff 11.
[0512] For some applications, the flow resistance is placed not between inflatable cuff 11 and fluid reservoir 120, but instead at the at least one site 139 along liquid column container 118 at which liquid column container 118 is open to atmosphere 99, as described hereinabove. Flow resistance anywhere along the fluid communication from inflatable cuff 11 all the way to atmosphere 99 is sufficient to create the desired effect.
[0513] For some applications, liquid column container 118 is arranged such that, when (a) liquid column container 118 is oriented in the aligned orientation and (b) the pressure of the gas in fluid reservoir 120 is 25 cm H2O: an increase in a volume of the gas in fluid reservoir 120 of up to 2 cc results in less than a 10 cm H2O increase in the pressure of the gas in fluid reservoir 120, such as less than a 6 cm H2O increase in the pressure of the gas in fluid reservoir 120, e.g., less than a 5 cm H2O or less than a 4 cm H2O increase. Alternatively or additionally, for some applications, liquid column container 118 is arranged such that, when (a) liquid column container 118 is oriented in the aligned orientation, and (b) the pressure of the gas in fluid reservoir 120 is 25 cm H2O: a decrease in the volume of the gas in fluid reservoir 120 of up to 1 cc results in less than a 6 cm H2O decrease in the pressure of the gas in fluid reservoir 120, e.g., less than a 5 cm H2O or less than a 4 cm H2O decrease. For some applications, liquid column container 118 is shaped so as to provide asymmetric regulation of pressure; for example, liquid column container 118 may be conical. Alternatively or additionally, for some applications, pressure indicia markings 126 are arranged to indicate a pressure of 25 cm H2O at an axial location of relevant-range fluid compartment 123 other than an axial center of relevant-range fluid compartment 123.
[0514] Typically, cuff pressure stabilizer 100 does not comprise any membranes in contact with liquid 121, and does not comprise any membranes in a fluid path between liquid 121 and atmosphere 99.
[0515] Typically, cuff pressure stabilizer 100 does not comprise a spring for measuring the pressure of the gas in fluid reservoir 120.
[0516] For some applications, cuff pressure stabilizer 100 further comprises an orientation-sensitive valve assembly 150, which comprises a valve 156 (e.g., a solenoid valve, or an elastically biased gate). Orientation-sensitive valve assembly 150 is arranged to automatically assume: [0517] an open state when an orientation of cuff pressure stabilizer 100 differs from the aligned orientation by no more than a constant number of degrees, and [0518] a reduced-flow state when the orientation of cuff pressure stabilizer 100 differs from the aligned orientation by more than the constant number of degrees.
[0519] Typically, the constant equals between 5 and 45 degrees, such as between 5 and 20 degrees.
[0520] Valve 156 is configured to reduce fluid communication thereacross by at least 90% when in the reduced-flow state compared to when in the open state, such as to entirely block fluid communication thereacross when in the reduced-flow state. Such reduced fluid communication serves as a safety feature and/or to prevent spillage of the fluid during storage and shipment of the device. For some applications, valve 156 is arranged in a fluid path between inflation lumen proximal port connector 134 and fluid reservoir 120.
[0521] For some applications, orientation-sensitive valve assembly 150 comprises electronic components, such as an orientation sensor 155 (e.g., comprising an accelerometer), which is configured to sense the orientation of cuff pressure stabilizer 100, and a battery 151. For some applications, orientation-sensitive valve assembly 150 further comprises one or more alignment indicators 152 and 153 (e.g., LEDs).
[0522] Reference is now made to
[0523] For some applications, cuff pressure stabilizer 200 comprises an orientation-sensitive valve assembly 250 that is mechanical and non-electrical. For some applications, orientation-sensitive valve assembly 250 comprises: [0524] a moving weight 261, which is typically spherical; [0525] a curved sliding/rolling surface 262, which is shaped to define an opening 267 therethrough at its bottom (when liquid column container 118 is oriented in the aligned orientation), the opening too small for moving weight 261 to pass through; [0526] a gas passage opening 263; [0527] a seal 264, which is shaped and arranged to seal gas passage opening 263 when seal 264 is up with respect to the Earth; [0528] an elastic element 265 (e.g., a spring), which is arranged to push seal 264 against gas passage opening 263; and [0529] a press-switch 266, which has (a) a first end that is fixed to seal 264 and passes through gas passage opening 263, and a (b) second end that passes through opening 267.
[0530] When cuff pressure stabilizer 100 differs from the aligned orientation by more than the constant number of degrees mentioned above with reference to
[0531] When cuff pressure stabilizer 100 differs from the aligned orientation by no more than the constant number of degrees, moving weight 261 slides or rolls away from opening 267, such that moving weight 261 does not press on the second end of press-switch 266, such as shown in
[0532] Reference is now made to
[0533] Liquid column container 118 is shaped so as to define a wider portion 323 and a narrower portion 322 axially between wider portion 323 and fluid reservoir 120. Wider portion 323 has an average cross-sectional area, measured in (a) horizontal plane 135, described hereinabove with reference to
[0534] Typically, all axial locations along liquid column container 118 corresponding to the pressure of the gas in fluid reservoir 120 at the respective plurality of pressures in relevant pressure range 127 fall within wider portion 323. However, this may not be the case if a healthcare worker axially adjusts wider portion 323 beyond normal clinical limits (in configurations in which cuff pressure stabilizer 300 is arranged to provide an adjustable distance between wider portion 323 and fluid reservoir 120, such as described hereinbelow with reference to
[0535] For some applications, wider portion 323 has a length of: [0536] at least 2 cm, such as at least 3 cm, and/or no more than 10 cm, such as no more than 5 cm, [0537] the quotient of (a) at least 6 cm, such as at least 9 cm, and/or no more than 30 cm, such as no more than 15 cm, divided by (b) the specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, and/or [0538] the quotient of (a) at least 6 cm, such as at least 9 cm, and/or no more than 30 cm, such as no more than 15 cm, divided by (b) the specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm.
[0539] For some applications, when liquid column container 118 is oriented in the aligned orientation, wider portion 323 has an inner cross-sectional area, measured in horizontal plane 135 and/or the above-mentioned plane, at a plurality of (such as at most or all) axial locations along wider portion 323, of (a) at least 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2), (b) at least the product of 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2) and a specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, (c) at least the product of 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2) and a specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm, and/or (d) less than 2 cm2. For some applications, when liquid column container 118 is oriented in the aligned orientation, wider portion 323 has an average inner cross-sectional area, measured in horizontal plane 135 and/or the above-mentioned plane, of (a) at least 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2), (b) at least the product of 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2) and a specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, (c) at least the product of 0.16 cm2 (e.g., at least 0.25 cm2, 0.5 cm2, or 1 cm2) and a specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm, and/or (d) less than 2 cm2. For some applications, when liquid column container 118 is oriented in the aligned orientation, narrower portion 322 has an inner cross-sectional area, measured in horizontal plane 135 and/or the above-mentioned plane, of less than 0.16 cm2, such as less than 0.09 cm2, at most or all axial locations along narrower portion 322.
[0540] Reference is now made to
[0541] For some applications, cuff pressure stabilizer 300 is arranged such that the adjustable distance can vary by at least 1 cm. Alternatively or additionally, for some applications, cuff pressure stabilizer 300 is arranged such that the adjustable distance can vary by (a) at least the quotient of (i) 3 cm divided by (ii) the specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, and/or (b) at least the quotient of (i) 3 cm divided by (ii) the specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm.
[0542] For some applications, cuff pressure stabilizer 300 comprises a mechanical user control element 360, which is arranged to set the adjustable distance, for example by rotation, e.g., with respect to a threaded connector 361 that is fixed to wider portion 363. Alternatively, mechanical user control element 360 may axially slide with respect to casing 110 upon application of a sufficient force to overcome friction preventing such sliding.
[0543] For some applications, such as shown in
[0544] For other application (configuration not shown), fluid reservoir 120 is axially-slidably coupled to casing 110. Typically, for these applications, wider portion 323 of liquid column container 118 is fixed to casing 110.
[0545] For some applications, wider portion 323 of liquid column container 118 has a target-pressure indicator marker 369 (e.g., a horizontal line), which is axially slidable with respect to pressure indicia markings 126, which, as mentioned above, are typically provided on casing 110. The healthcare worker may set target-pressure indicator marker 369 to indicate a desired target pressure in inflatable cuff 11, and then inflate inflatable cuff 11 at least approximately to this target pressure. Such setting of target-pressure indicator marker 369, by axially moving target-pressure indicator marker 369 with respect to pressure indicia markings 126, has the effect of adjusting the adjustable distance between wider portion 323 of liquid column container 118 and fluid reservoir 120.
[0546] Target-pressure indicator marker 369 is disposed on wider portion 323 so as to delineate (a) an upper portion of wider portion 323 above target-pressure indicator marker 369 and (b) a lower portion of wider portion 323 below target-pressure indicator marker 369. For some applications, the volume of the upper portion equals: [0547] at least 100% of the volume of the lower portion, such as at least 150%, e.g., between 150% and 250%, such as 200% of the volume of the lower portion, [0548] between 1 and 2.5 cc, e.g., 2 cc, [0549] the quotient of (a) between 3 and 10 cc, e.g., between 4 and 8 cc divided by (b) the specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, and/or [0550] the quotient of (a) between 3 and 10 cc, e.g., between 4 and 8 cc divided by (b) the specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm.
For some applications, the volume of the lower portion equals: [0551] between 0.75 and 1.25 cc, e.g., 1 cc, [0552] the quotient of (a) between 1.5 and 5 cc, e.g., between 2 and 4 cc divided by (b) the specific gravity of liquid 121 with reference to water at 4 degrees Celsius at 1 atm, and/or [0553] the quotient of (a) between 1.5 and 5 cc, e.g., between 2 and 4 cc divided by (b) the specific gravity of liquid 121 with reference to water at 20 degrees Celsius at 1 atm.
[0554] For some applications, at least an axial portion of narrower portion 322 of liquid column container 118 is flexible, so as to provide a variable axial length to narrower portion 322. For some of these applications, the at least an axial portion of narrower portion 322 of liquid column container 118 is elastic. For other applications, at least an axial portion of narrower portion 322 of liquid column container 118 is telescopically adjustable, so as to provide a variable axial length to narrower portion 322.
[0555] Reference is still made to
[0556] For some applications, at each of all axial locations along narrower portion 322 of liquid column container 118, liquid column container 118: [0557] has a largest inner dimension D.sub.1 equal to a greatest distance between any two points 324A and 324B within liquid column container 118 in (a) horizontal plane 135, described hereinabove with reference to
At most or all (e.g., all) of the axial locations along narrower portion 322 of liquid column container 118, a ratio of (a) the largest inner dimension D.sub.1 to (b) the diameter D.sub.2 of circle 326 equals at least 2:1, such as at least 4:1, e.g., at least 8:1. It is to be understood that circle 326 is not an element of cuff pressure stabilizer 300, but rather a geometric construct used to describe a structural property of cuff pressure stabilizer 300.
[0559] For some applications, the largest inner dimension D.sub.1 equals at least 4 mm at most or all of the axial locations along narrower portion 322 of liquid column container 118, such as at least 6 mm, e.g., at least 8 mm Alternatively or additionally, for some applications, the diameter D.sub.2 of circle 326 is no more than 4 mm at most or all of the axial locations along narrower portion 322 of liquid column container 118, such as no more than 2 mm, e g , no more than 1 mm, such as no more than 0.5 mm
[0560] For some applications, at most or all of the axial locations along narrower portion 322 of liquid column container 118, liquid column container 118 has a non-circular cross-sectional shape, such as a rectangle, an oblong shape, an ellipse, or a crescent. For applications in which the cross-sectional shape is a rectangle, a length L of the rectangular typically equals at least 200% of a width W of the rectangle, such as at least 300% or at least 400%. For applications in which the cross-sectional shape is an ellipse, a length of the major axis of the ellipse typically equals at least 200% of a length of the minor axis of the ellipse, such as at least 300% or at least 400%.
[0561] Alternatively or additionally, for some applications, at each of the axial locations along narrower portion 322 of liquid column container 118, at least 80% of the inner cross-sectional area is within 1 mm of an inner surface 328 of liquid column container 118, such as within 0.75 mm, e.g., within 0.5 mm, such as within 0.2 mm, of inner surface 328. For some applications, at each of the axial locations along narrower portion 322 of liquid column container 118, less than 10% of the inner cross-sectional area is within 0.1 mm, such as within 0.2 mm, of inner surface 328 of liquid column container 118. For some applications, the inner cross-sectional area is less than 0.09 cm2 at most or all axial locations along narrower portion 322 of liquid column container 118, when liquid column container 118 is oriented in the aligned orientation.
[0562] Reference is made to
[0563] Reference is now made to
[0564] Cuff pressure stabilizer 500 comprises a fluid reservoir 524 and a liquid column container 518. Liquid column container 518 is (a) open to atmosphere 99 at at least one site along liquid column container 518, (b) in fluid communication with fluid reservoir 524, and (c) in communication with the inflation lumen proximal port connector 134 via fluid reservoir 524. Cuff pressure stabilizer 500 comprises a buffer module 550, which is configured to provide automatic pressure regulation of inflatable cuff 11, while simultaneously continuously displaying the pressure in inflatable cuff 11. Cuff pressure stabilizer 500 further comprises an indicator module 520, which continuously displays the pressure in inflatable cuff 11.
[0565] Cuff pressure stabilizer 500 further comprises liquid 121, which is contained (a) in fluid reservoir 524, (b) in liquid column container 518, or (c) partially in fluid reservoir 524 and partially in liquid column container 518. Like cuff pressure stabilizer 100, cuff pressure stabilizer 500 has a plurality of pressure indicia markings 126 distributed along liquid column container 518 for measuring a height of liquid 121 in liquid column container 518. Typically, pressure indicia markings 126 are distributed evenly throughout at least relevant pressure range 127 of 23-27 cm H2O.
[0566] Typically, liquid 121 has (a) a density of between 1.5 and 5 g/cm3 at 4 degrees Celsius at 1 atm, such as less than 3.5 g at 4 degrees Celsius at 1 atm, e.g., less than 3 g at 4 degrees Celsius at 1 atm, e.g., between 1.5 and 3.5 g/cm3, such as between 1.5 and 3 g/cm3, and/or (b) a density of between 1.5 and 5 g/cm3 at 20 degrees Celsius at 1 atm, such as less than 3.5 g at 20 degrees Celsius at 1 atm, e.g., less than 3 g at 20 degrees Celsius at 1 atm, e.g., between 1.5 and 3.5 g/cm3, such as between 1.5 and 3 g/cm3. Such a density provides high resolution pressure readings in the above-mentioned relevant pressure range 127 of 23-27 cm H2O, without requiring liquid column container 518 to be very long and unwieldy, such as if liquid 121 was H2O.
[0567] For some applications, liquid 121 has (a) a viscosity of no more than 25 times a viscosity of water at 4 degrees Celsius at 1 atm, such as no more than 15, no more than 10, or no more than 5 times the viscosity of water at 4 degrees Celsius at 1 atm, and/or (b) a viscosity of no more than 25 times a viscosity of water at 20 degrees Celsius at 1 atm, such as no more than 15, no more than 10, or no more than 5 times the viscosity of water at 20 degrees Celsius at 1 atm. For some applications, liquid 121 comprises a solution of crystals (solute) dissolved in a liquid solvent (typically water), having a mass percent of between 65% and 85% (e.g., between 75% and 85%) (i.e., the mass of the liquid solvent (typically water) is only between 15% and 35% of the total mass of the solution). The dilution is selected based on the desired density of the liquid.
[0568] Typically, liquid 121 is non-toxic. As used in the present application, including in the claims, “non-toxic” has the meaning generally understood in the medical arts, i.e., that the full quantity of liquid 121 of the cuff pressure stabilizer, even if it is swallowed by the patient or comes in contact with the patient's skin, will not produce personal injury or illness to the patient. (The liquid is still “non-toxic” if it causes mild irritations upon coming contact in with the eyes (which is not an intended use of the liquid).) For example, criteria for ascertaining whether a substance is “toxic” are provided in the U.S. Federal Hazardous Substances Act (FHSA) and the Chemicals Act of Germany (Chemikaliengesetz—ChemG), as amended in 2008.
[0569] Typically, liquid 121 is non-flammable. Typically, liquid 121 is odorless. For some applications, liquid 121 comprises a tungstate-based liquid, e.g., selected from the group consisting of sodium polytungstate, sodium metatungstate, lithium polytungstate, and lithium metatungstate. For some applications, liquid 121 comprises at least two liquids, at least one of which has the density of between 1.5 and 5 g/cm3 at 4 degrees Celsius at 1 atm, and at least one of which has a density of less than 1.5 g/cm3 at 4 degrees Celsius at 1 atm. For some applications, liquid 121 comprises at least two liquids, at least one of which has the density of between 1.5 and 5 g/cm3 at 20 degrees Celsius at 1 atm, and at least one of which has a density of less than 1.5 g/cm3 at 20 degrees Celsius at 1 atm.
[0570] For some applications, a volume of liquid 121 is at least 0.5 cc, no more than 4 cc, and/or between 0.5 and 4 cc, such as at least 1 cc, no more than 2 cc, and/or between 1 and 2 cc.
[0571] For some applications, liquid column container 518 is in pressure communication with inflation lumen proximal port connector 134 via fluid reservoir 524. For some of these applications, fluid reservoir 524 comprises at least one wall 521 that comprises a pressure-communicating movable wall 554, and liquid column container 518 is in pressure communication with inflation lumen proximal port connector 134 via pressure-communicating movable wall 554 of fluid reservoir 524. For some applications (as shown), pressure-communicating movable wall 554 comprises a flexible membrane, which typically is elastic or pliable, while for other applications (not shown), pressure-communicating movable wall 554 comprises another movable structure, such as bellows.
[0572] For some applications, cuff pressure stabilizer 500 comprises a gas container 523, which (a) extends to inflation lumen proximal port connector 134, (b) contains some of the gas, (c) is not in liquid communication with fluid reservoir 524, and (d) comprises at least one wall that comprises a volume-compensation movable wall 552, which is in pressure communication with atmosphere 99 on the other side of the movable wall. For some applications (as shown), volume-compensation movable wall 552 comprises a flexible membrane, which typically is elastic or pliable, while for other applications (not shown), volume-compensation movable wall 552 comprises another movable structure, such as bellows. When inflatable cuff 11 is squeezed and its volume therefore decreases, gas is pushed from the inflatable cuff into gas container 523. As a result, volume-compensation movable wall 552 moves (e.g., stretches, for applications in which the movable wall comprises a flexible membrane) and thereby increases the total volume of gas container 523 to accommodate the addition gas. In addition, a liquid upper surface 529 of liquid 121 in liquid column container 518 moves upward, also increasing the volume of gas container 523.
[0573] For some of these applications, fluid reservoir 524 comprises the at least one wall 521 that comprises pressure-communicating movable wall 554, and liquid column container 518 is in pressure communication with gas container 523 via pressure-communicating movable wall 554 of fluid reservoir 524. Pressure-communicating movable wall 554 thus prevents fluid communication between fluid reservoir 524 and gas container 523, while allowing pressure communication therebetween. Typically, pressure-communicating movable wall 554 is disposed at least partially within gas container 523.
[0574] Pressure-communicating movable wall 554 is typically deformable (e.g., elastic and/or pliable). As a result, when the gas pressure increases in gas container 523, the gas presses and moves pressure-communicating movable wall 554, thereby pushing liquid 121 in fluid reservoir 524 upward within liquid column container 518, and thus also elevating liquid upper surface 529 of liquid 121 in liquid column container 518. For some applications, pressure-communicating movable wall 554 is supported at its bottom by a rigid platform 556, which maintains the lowest point of liquid 121 at a fixed reference height.
[0575] For some applications, gas container 523 comprises a buffer chamber 564, which is shaped so as to define a chamber inlet port 558 that is in fluid communication with inflation lumen proximal port connector 134, such as via gas inlet 141. For some applications, buffer chamber 564 has a volume of at least 1 cc when a pressure of the gas in buffer chamber 564 is 25 cm H2O. For some applications, a volume of buffer chamber 564 increases by at least 1 cc, such as by at least 2 cc, and/or by no more than 5 cc, when a pressure of gas 559 in buffer chamber 564 increases from 25 cm H2O to 30 cm H2O. For some applications, at least one wall of buffer chamber 564 comprises volume-compensation movable wall 552, described above.
[0576] Buffer chamber 564 typically comprises a buffer chamber casing 537. For some applications, pressure-communicating movable wall 554 is disposed at least partially within buffer chamber 564, e.g., within buffer chamber casing 537. For some of these applications, buffer chamber casing 537 is shaped so as to define, in addition to buffer chamber 564, an enclosed volume-compensation movable wall expansion space 553, into which volume-compensation movable wall 552 can expand. For such applications, buffer chamber casing 537 typically is shaped so as to define a buffer chamber air environment port 557 between enclosed volume-compensation movable wall expansion space 553 and atmosphere 99.
[0577] For some applications, liquid column container 518 comprises a dissolvable wall portion 560 that is dissolvable in water. Typically, dissolvable wall portion 560 defines a perforation therethrough that is configured to become permeable to liquid 121 through the perforation after total time of at least 3 days, e.g., at least 7 days, at least 10 days, or at least 14 days, and/or less than 30 days of contact with liquid 121. Typically, dissolvable wall portion 560 remains impermeable to liquid 121 for at least 48 hours, e.g., at least 1 week, at least 2 weeks, or at least 3 weeks, of contact between liquid 121 and dissolvable wall portion 560. For some applications, before the first use of cuff pressure stabilizer 500, an elongate plug is disposed in liquid column container 518 (typically through opening 142) and reaches below the bottom end of dissolvable wall portion 560, thereby preventing liquid 121 from coming into contact with dissolvable wall portion 560 until the plug is removed. Dissolvable wall portion 560 may preserve sterility of cuff pressure stabilizer 500 by preventing reuse of the stabilizer for more than one patient.
[0578] For some applications, when liquid column container 518 is oriented in an aligned orientation in which pressure indicia markings 126 reflect, to within 1 cm H2O, pressure of the gas in buffer chamber 564 at least in relevant pressure range 127 of 23-27 cm H2O: dissolvable wall portion 560 is disposed at least partially below an axial location along liquid column container 518 corresponding to a pressure of the gas in buffer chamber 564 of 23 cm H2O. For some applications, when liquid column container 518 is oriented in the aligned orientation and the pressure of the gas in buffer chamber 564 equals ambient air pressure, dissolvable wall portion 560 is disposed above liquid upper surface 529 of liquid 121 in liquid column container 518.
[0579] Reference is now made to
[0580] As illustrated in
[0581] Reference is now made to
[0582] Cuff pressure stabilizer 600 comprises a fluid reservoir 624, and a liquid column container 618, which is (a) open to atmosphere 99 at at least one site along liquid column container 618, (b) in fluid communication with fluid reservoir 624, and (c) in communication with the inflation lumen proximal port connector 134 via fluid reservoir 624. Cuff pressure stabilizer 600 comprises a buffer module 650, which is configured to provide automatic pressure regulation of inflatable cuff 11, while simultaneously continuously displaying the pressure in inflatable cuff 11. Cuff pressure stabilizer 600 further comprises an indicator module 620, which continuously displays the pressure in inflatable cuff 11.
[0583] Typically, fluid reservoir 624 contains some of gas 559, and liquid column container 618 is in fluid communication with inflation lumen proximal port connector 134 via fluid reservoir 624. Consequently, gravity causes gas 559 in fluid reservoir 624 to be above the portion of liquid 121 in fluid reservoir 624.
[0584] For some applications, fluid reservoir 624 extends to inflation lumen proximal port connector 134, and comprises at least one wall 630 that comprises a volume-compensation movable wall 652, which is in pressure communication with atmosphere 99. For some applications, fluid reservoir 624 comprises a buffer chamber 664, which is shaped so as to define a chamber inlet port 658 that is in fluid communication with inflation lumen proximal port connector 134, such as via gas inlet 141. For some of these applications, buffer chamber 664 comprises the at least one wall 630 that comprises volume-compensation movable wall 652. For some applications, buffer chamber 664 has a volume of at least 2 cc when gas 559 in buffer chamber 664 is at a pressure of 25 cm H2O.
[0585] In the resting state illustrated in
[0586] As illustrated in
[0587] For some applications, fluid reservoir 624 contains some of gas 559, and when liquid column container 618 is oriented in an aligned orientation in which pressure indicia markings 126 reflect, to within 1 cm H2O, pressure of the gas in fluid reservoir 624 at least in relevant pressure range 127 of 23-27 cm H2O: dissolvable wall portion 560 is disposed at least partially below an axial location along liquid column container 618 corresponding to a pressure of the gas in fluid reservoir 624 of 23 cm H2O. For some applications, when liquid column container 618 is oriented in an aligned orientation and the pressure of gas 559 in fluid reservoir 624 equals ambient air pressure, dissolvable wall portion 560 is disposed above liquid upper surface 529 of liquid 121 in liquid column container 618.
[0588] Reference is now made to
[0589] For some applications, buffer chamber 664 comprises a buffer chamber casing 837. For some applications, volume-compensation movable wall 652 is disposed at least partially within buffer chamber 664, e.g., within buffer chamber casing 837. Buffer chamber casing 837 typically is shaped so as to define buffer chamber air environment port 557 between enclosed volume-compensation movable wall expansion space 553 and atmosphere 99.
[0590] Typically, cuff pressure stabilizer 800 comprises a coupling element 828, which may comprise, for example, a strap (as shown), a gripper (not shown), or a clamp (not shown), which is coupleable to a vertical pole (e.g., a vertical IV pole), such as shown for the prototypes in
[0591] For some applications, buffer chamber 664 is shaped so as to define an internal spill-prevention element 880, which may be shaped as an inverted bottle neck. Spill-prevention element 880 creates a pool such that if the device is laid on its side or even turned upside down, liquid 121 will not spill by gravity through buffer chamber air environment port 557.
[0592] For some applications, cuff pressure stabilizer 800 comprises an on/off valve 885, which enables/disables fluid communication between buffer chamber 664 and liquid column container 618. In the illustrated configuration, valve 885 is switched on/off by rotation around the vertical axis, e.g., upon turning by 180 degrees, a fluid passage 887 to liquid column container 618 is turned away and instead a wall 886 seals the fluid communication between buffer chamber 664 and liquid column container 618.
[0593] For some applications, cuff pressure stabilizer 800 comprises a pressure-release chamber 890. Pressure-release chamber 890 is typically sized to have a volume larger than that of the full liquid content. If the pressure rises to a level above that of a level of the bottom of pressure-release chamber 890, liquid 121 is collected within pressure-release chamber 890. Liquid 121 is the only gas-seal that prevents escape of gas from the cuff to atmosphere 99. Therefore, if the cuff pressure rises to a pressure substantially above the level of the bottom of pressure-release chamber 890, all of liquid 121 is collected in pressure-release chamber 890, and gas escapes from the cuff to atmosphere 99, thereby releasing the excess pressure. The level of liquid 121 then falls again to recreate the gas seal so as to prevent further gas leakage from the cuff to atmosphere 99. Altogether, pressure-release chamber 890 operates as an effective pressure-release valve in which the pressure limit is set by the height of pressure-release chamber 890.
[0594] Reference is now made to
[0595] Reference is now made to
[0596] Although cuff pressure stabilizers 100, 200, 300, 500, 600, and 800 have been described as being used with inflatable cuff 11 of tracheal ventilation tube 10, cuff pressure stabilizers 100, 200, 300, 500, 600, and 800 may alternatively be used with other inflatable chambers of other medical devices or non-medical devices. For example, the inflatable chamber may be a Foley catheter balloon, a gastric balloon, a balloon of colonoscope, or a balloon of an endoscope.
[0597] In the description and claims of the present application, each of the verbs, “comprise,” “include” and “have,” and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb. The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element. The term “including” is used herein to mean, and is used interchangeably with, the phrase “including but not limited to.” The term “or” is used herein to mean, and is used interchangeably with, the term “and/or,” unless context clearly indicates otherwise. The term “such as” is used herein to mean, and is used interchangeably, with the phrase “such as but not limited to.”
[0598] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present patent specification, including definitions, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
[0599] For brevity, some explicit combinations of various features are not explicitly illustrated in the figures and/or described. It is now disclosed that any combination of the method or device features disclosed herein can be combined in any manner—including any combination of features—any combination of features can be included in any embodiment and/or omitted from any embodiments.
[0600] As used in the present application, including in the claims, a “fluid” comprises liquid and/or gas.
[0601] Although applications of the present invention have generally been described as for use with tracheal ventilation tube 10, they may also be used with other catheters, such as tracheostomy catheters.
[0602] The scope of the present invention includes embodiments described in the following applications, which are assigned to the assignee of the present application and are incorporated herein by reference. In an embodiment, techniques and apparatus described in one or more of the following applications are combined with techniques and apparatus described herein:
[0603] PCT Publication WO/2012/131626 to Einav et al.
[0604] GB 2482618 A to Einav et al.;
[0605] UK Application GB 1119794.4, filed Nov. 16, 2011;
[0606] U.S. Provisional Application 61/468,990, filed Mar. 29, 2011;
[0607] U.S. Provisional Application 61/473,790, filed Apr. 10, 2011;
[0608] U.S. Provisional Application 61/483,699, filed May 8, 2011;
[0609] U.S. Provisional Application 61/496,019, filed Jun. 12, 2011;
[0610] U.S. Provisional Application 61/527,658, filed Aug. 26, 2011;
[0611] U.S. Provisional Application 61/539,998, filed Sep. 28, 2011;
[0612] U.S. Provisional Application 61/560,385, filed Nov. 16, 2011;
[0613] U.S. Provisional Application 61/603,340, filed Feb. 26, 2012;
[0614] U.S. Provisional Application 61/603,344, filed Feb. 26, 2012;
[0615] U.S. Provisional Application 61/609,763, filed Mar. 12, 2012;
[0616] U.S. Provisional Application 61/613,408, filed Mar. 20, 2012;
[0617] U.S. Provisional Application 61/635,360, filed Apr. 19, 2012;
[0618] U.S. Provisional Application 61/655,801, filed Jun. 5, 2012;
[0619] U.S. Provisional Application 61/660,832, filed Jun. 18, 2012;
[0620] U.S. Provisional Application 61/673,744, filed Jul. 20, 2012;
[0621] PCT Publication WO 2013/030821 to Zachar et al.;
[0622] U.S. Pat. No. 8,999,074 to Zachar et al.;
[0623] U.S. Provisional Application 62/305,567, filed Mar. 9, 2016;
[0624] U.S. Provisional Application 62/402,024, filed Sep. 30, 2016; and
[0625] U.S. Provisional Application 62/405,115, filed Oct. 6, 2016
[0626] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.