Patent Application
20230310722
The present disclosure is directed to pressure sensors, including optical pressure sensors for automated peritoneal dialysis (APD) systems, and associated systems, devices, and methods. For example, pressure sensors configured in accordance with some embodiments of the present technology are configured to measure pressure of isolated solutions flowing through disposable sets of APD systems.
Dialysis is used to (a) remove excess fluid and toxins in persons with kidney failure and (b) correct electrolyte concentrations in their blood. Peritoneal dialysis is a form of dialysis that uses a peritoneum in an individual’s abdomen as a membrane through which fluid and dissolved substances are exchanged with blood. More specifically, a solution is introduced into and removed from the individual’s abdomen via a surgically installed catheter.
In continuous ambulatory dialysis (CAPD), solution is manually introduced and removed (e.g., at regular intervals throughout the day). In particular, the catheter is connected to a disposable set that includes (i) a source bag (e.g., hung on a drip stand) containing new solution, (ii) a drain bag configured to collect waste solution, and (iii) various fluid lines connecting the source bag and the drain bag to the catheter. Waste solution from the individual’s lower abdomen is drained into the drain bag via the catheter, and new solution is introduced into the individual’s lower abdomen via the catheter. After such an exchange treatment is complete, the disposable set is discarded.
APD (also known as continuous cycling peritoneal dialysis (CCPD)) is similar to CAPD except that the exchange treatment is automated using an APD machine or cycler. More specifically, a pump included in the APD machine is used to introduce and remove the solution (e.g., while the individual sleeps). Each APD exchange treatment may include one or more cycles of introducing and removing solution from the individual’s abdomen.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on clearly illustrating the principles of the present disclosure. The drawings should not be taken to limit the disclosure to the specific embodiments depicted, but are for explanation and understanding only.
The present disclosure is directed to pressure sensors and associated systems, devices, and methods. In the illustrated embodiments below, pressure sensors of the present technology are primarily described in the context of optical pressure sensors measuring pressure of dialysate solution within or flowing through disposable sets of APD systems. Pressure sensors configured in accordance with various embodiments of the present technology, however, can be incorporated into and/or used by other systems, including hemodialysis systems and/or other medical or non-medical systems. Additionally, pressure sensors of the present technology can include non-optical pressure sensors and/or can be used to measure pressure of solutions or fluids besides dialysate solution, such as water, saline, blood, and/or other low viscous fluids. Furthermore, a person skilled in the art will understand that (i) the technology may have additional embodiments than illustrated in
Many systems include pumps (e.g., peristaltic or other types of pumps in which fluid is isolated from pumping mechanisms) configured to regulate, control, and/or otherwise affect fluid flow through other components of the systems. For example, pumps are commonly used to perform blood transfusions and cardiopulmonary bypass operations. Pumps are also used in many industrial applications, such as agriculture or food dispensing. The act of pumping fluid creates fluid pressures within a system that can vary as the system is operated. In some systems, fluid pressures must remain within predetermined operating ranges to ensure safe or proper operation of the systems. For example, in some medical systems, when fluid pressure exceeds or violates safe operating limits, a patient may experience harm or discomfort. Thus, pressure sensors can be employed to monitor fluid pressure and ensure that the fluid pressures remain within safe operating ranges.
For certain systems (e.g., medical systems, laboratory systems, food dispensing systems, etc.), measuring and monitoring fluid pressure can be difficult because a fluid flowing through the systems must remain isolated to prevent contamination. In some of these systems, a disposable set of fluid lines and/or other components is used to convey fluid from a sterile container to a destination (e.g., a patient, a storage container, etc.). The disposable set can be pre-sterilized and disposed of after a single use to minimize the risk of contamination.
To measure fluid pressure in a disposable set, many systems use a pressure transducer that operates by converting (a) pressure of a fluid against a surface in contact with the fluid into (b) a displacement of some mechanical element (e.g., a force sensor) of the pressure transducer. Commonly, the displacement is then converted into an electrical signal that can be used to monitor the fluid pressure. For example, some industrial systems thread or press a pressure transducer into a port on a container or pipe. Such a solution has two primary drawbacks: (1) any port that opens into a sterile containment system is a potential source of contamination, and (2) the pressure transducer itself must be sterilized between uses and remains a potential source of contamination.
Another approach includes placing a thin, flexible membrane over an opening into a fluid containment system. The membrane has excess material so that it can deform with little resistance. A pressure transducer is centered on the membrane, and internal fluid pressure forces the membrane against a surface of the pressure transducer. A measured force can be used to approximate the internal pressure of fluid.
The above approach has previously been employed in hemodialysis systems. In a hemodialysis system, however, blood pressure ranges from about +6 kPa to about +30 kPa. Thus, the above approach is typically only used to measure positive fluid pressures. In addition, the membrane used in such a system is often fragile (e.g., easily deformed, extremely flexible, not rigid, not semi-rigid, etc.). Furthermore, the surface of the pressure transducer in contact with membrane is typically (a) planar and (b) much smaller than the opening in the disposable set transporting blood. When the planar surface contacts and/or deforms the membrane, the membrane is often stretched (e.g., at edges of the planar surface) and/or is not uniformly or smoothly deformed. This can lead to inaccuracies in pressure measurements captured by the pressure transducer and/or to inelastic deformation of the membrane. Furthermore, the planar surface does not fully support the membrane when the membrane is deformed, and the size of the planar surface (being much smaller than the opening) requires precise positioning of the surface at the center of the membrane for accurate measurement of blood pressure. As a result, such pressure transducers are often sensitive to variations in (i) thicknesses or moduli between different membranes of different disposable sets and/or (ii) different placements of the planar surface is relation to the center of the membrane. Therefore, complex analysis and experimentation is often required for each membrane and/or positioning of the planar surface to determine a relationship between a force measured by the pressure transducer and pressure of blood within the hemodialysis system.
Another approach that is used in applications in which high accuracy and measurement of low pressures are not needed involves measuring pressure in a soft elastomeric tube containing a pressurized fluid. The tube is partially flattened between two plates that are pressed against the tube from opposite sides. One of the plates is mounted on a force sensor. When fluid pressure within the tube works to restore a circular cross-section of the tube, the fluid pressure presses the tube against the plates and registers a force on the force sensor. The force can be used to approximate the pressure of the fluid within the tube.
In this approach, however, it is difficult (a) to maintain a consistent deformation of the tube and/or (b) to ensure that a force applied to restore the circular cross-section of the tube is fully transmitted to the force sensor. In addition, a large portion of a force measured by the force sensor is often due to a force provided by the tube itself to restore its circular cross-section rather than due to pressure of the fluid. Furthermore, this approach is often highly sensitive to variations in wall thickness, hardness, and/or other properties between different tubes. Moreover, it is difficult to measure negative pressures using this approach.
Other than pressure transducers, another approach used to measure fluid pressure in a disposable set involves including an electronic pressure sensor in the disposable set. In this approach, electrical leads of the sensor extend from an interior of the disposable set to contacts on an exterior of the disposable set. The disposable set (including the electronic pressure sensor) is sterilized before use and is then thrown away after use to eliminate the risk of contamination. Such an approach is therefore expensive and wasteful as the electronic pressure sensor is used only once.
One other approach is commonly used in APD systems in which dialysate is pumped into and out of a patient’s body. More specifically, APD systems typically employ systems that control fluid pressure by measuring air pressure external to the isolated, sterile dialysate. Such systems are often extremely expensive and complex.
To address the shortcomings of the approaches described above, the inventors have developed pressure sensors and associated systems, devices, and methods that are expected to safely, accurately, and affordably measure pressure of an isolated fluid (e.g., within or flowing through a disposable set). In one embodiment, a diaphragm is positioned over an opening of a cavity in a disposable set that includes one or more fluid lines. The diaphragm is affixed to the disposable set about a periphery of the opening. The APD system further includes a pressure sensor configured to measure a pressure of fluid flowing through the disposable set. The pressure sensor can include a light source and a photosensor. The light source can be configured to direct light at a reflector on an outer surface of the diaphragm. The reflector can reflect light toward the photosensor, and the photosensor can detect a portion of the reflected light.
When the diaphragm is deformed due to pressure of fluid flowing through the disposable set, the amount of reflected light that strikes and is detected by the photosensor changes. Thus, the photosensor can detect an amount of light reflected from the diaphragm, and the pressure sensor can use the amount of light detected to determine a pressure of the fluid flowing through the disposable set. In this manner, pressure sensors of the present technology can be used to monitor fluid pressures flowing through a disposable set and/or to increase the likelihood that the fluid pressures remain within safe operating ranges.
Pressure sensors and associated systems, devices, and methods of the present technology therefore offer several advantages. For example, the pressure sensor of the present technology indirectly contacts fluid via a diaphragm of a disposable set. Thus, the fluid can remain isolated within the disposable set (thereby reducing the risk of contaminating the fluid), and the pressure sensor can be repeatedly reused to measure pressure of fluid flowing through a plurality of different disposable sets (thereby reducing waste and costs of the system). Furthermore, the present technology can (a) compensate for effects due to temperature, aging, and/or variations in voltage and/or current supplied to the light source and/or the photosensor, and/or (b) factor out portions of a measurement captured by one or more photosensors that are not due to pressure of a fluid acting on the diaphragm. Thus, pressure sensors of the present technology can accurately determine pressure of the fluid flowing through the disposable set. Additionally, pressure sensors of the present technology can measure both positive and negative pressures in fluid flowing through a disposable set. As such, the present technology is particularly apt for APD and other systems that involve both infusion and aspiration of fluid. For example, the present technology can measure both a range of positive fluid pressures (e.g., 0 kPa to +10 kPa) that is commonly observed when introducing dialysate into a patient during a cycle of an APD treatment and a range of negative fluid pressures (e.g., 0 kPa to -10 kPa) that is commonly observed when removing dialysate from a patient during a cycle of an APD treatment.
In some embodiments, the APD machine 110 can include a pump 101. The pump 101 can be a non-invasive pump. For example, the pump 101 can be a peristaltic pump or another suitable type of pump. In these and other embodiments, the pump 101 and/or the pressure sensor 103 can be removably or permanently integrated into the APD machine 110. Alternatively, the pump 101 and/or the pressure sensor 103 can be components of the system 100 that are separate from the APD machine 110.
Various components of the disposable set 107 can interface with the APD machine 110. For example, the cassette 104 and/or the damping device 102 can be installed on (e.g., held in place, attached to, supported by, etc.) the APD machine 110 during an exchange treatment. As another example, a portion of the disposable set 107 (e.g., the cassette 104, the damping device 102, or another component of the disposable set 107) that includes a diaphragm or membrane (not shown) can be mounted or otherwise positioned on the APD machine 110 and/or aligned with the pressure sensor 103, as discussed in greater detail below. The disposable set 107 can be configured to interface (a) with the pump 101, (b) with the pressure sensor 103, and/or (c) with a catheter 109 installed in a patient 108. For example, the disposable set 107 can connect to the catheter 109 (e.g., directly or via a transfer set (not shown)) such that the catheter 109 is placed in fluid communication with the source bag 105 and/or the drain bag 106.
In operation, the system 100 can be configured to introduce solution (e.g., dialysate or another fluid initially contained within the source bag 105) into the patient 108 via the APD machine 110 (e.g., using the pump 101) and/or via at least a first portion of the disposable set 107. The system 100 can further be configured to remove solution from the patient 108 by draining the solution into the drain bag 106 (e.g., using the pump 101) and/or via at least a second portion of the disposable set 107. In some embodiments, a single exchange treatment can include one or more cycles of introducing solution into the patient 108 and removing solution from the patient 108. After an exchange treatment is complete, the disposable set 107 can be discarded and a separate (e.g., a new) disposable set 107 can be used for a subsequent treatment.
The cassette 104 is configured to control and/or direct solution flow through the disposable set 107. In some embodiments, the cassette 104 can be integrated with the damping device 102. The damping device 102 of the disposable set 107 can be configured to control, reduce, and/or minimize amplitudes of pressure pulsations in solution flowing through the damping device 102 and/or other components of the disposable set 107. For example, the damping device 102 can reduce amplitudes of positive and/or negative pressure pulsations that are induced in the solution by the pump 101 such that solution flow through the disposable set 107 is smoothed. This is expected to reduce, minimize, and/or eliminate patient discomfort while solution is pumped into and/or out of the patient 108. In these and other embodiments, the damping device 102 can be configured to remove air bubbles from solution within the damping device 102, which is expected to further reduce, minimize, and/or eliminate the possibility of patient discomfort or harm during an exchange treatment.
The pressure sensor 103 can be configured to measure pressure of solution within or flowing through at least a portion of the disposable set 107. For example, as discussed in greater detail below, a portion of the disposable set can be aligned with the pressure sensor 103, and the pressure sensor 103 can be configured to measure pressure of solution flowing through the portion of the disposable set 107 without the pressure sensor 103 coming in contact with the solution. The portion of the disposable set 107 aligned with the pressure sensor 103 can include a portion (e.g., a diaphragm or membrane) of the damping device 102, a portion (e.g., a diaphragm or membrane) of the cassette 104, or the portion of the disposable set 107 aligned with the pressure sensor 103 can be separate from the damping device 102 and the cassette 104.
As shown in
In operation, the light source 225 is configured to direct light (e.g., at an angle) toward a diaphragm 213 that is aligned with the pressure sensor 203. In turn, light emitted from the light source 225 can reflect off an outer surface 213a of the diaphragm 213 (e.g., at an angle) and be redirected toward the photosensor 228. In this regard, the light source 225 and the photosensor 228 can be positioned along a common optical axis that is folded at an intersection with the outer surface 213a of the diaphragm 213. As discussed in greater detail below with respect to
In some embodiments, the pressure sensor 203 further includes a mount or housing 224 that can retain the light source 225 and/or the photosensor 228 in a desired position, orientation, and/or spacing. In these and other embodiments, the mount 224 can define at least a portion of a first light baffle 222a and/or at least a portion of a second light baffle 222b. Alternatively, the first light baffle 222a and/or the second light baffle 222b can be components of the system that are separate from the mount 224. The first light baffle 222a and/or the second light baffle 222b can be configured to shield (a) the photosensor 228 and/or light emitted from the light source 225 from (b) ambient light. Additionally, or alternatively, the first light baffle 222a can be configured to limit an area of light emitted from the light source 225 such that the light (a) exits an opening 221 in the mount 224 and/or in the first light baffle 222a and (b) primarily strikes a central area of the outer surface 213a of the diaphragm 213. In these and other embodiments, the second light baffle 222b can be configured to limit an area of light that (a) is reflected from the diaphragm 213, (b) reenters the opening 221 or another opening in the mount 224 and/or the second light baffle 222b, and/or (c) strikes the photosensor 228.
In some embodiments, the first light baffle 222a and/or the second light baffle 222b can include darkened (e.g., black) sidewalls. The darkened sidewalls can facilitate absorption of light that is emitted from the light source 225 off of the common optical axis and/or that is reflected from the diaphragm 213 off of the common optical axis. Stated another way, the darkened sidewalls of the first light baffle 222a and/or the second light baffle 222b can reduce, minimize, and/or eliminate the likelihood that light projected off of the common optical axis is reflected off of the sidewalls of the first light baffle 222a and/or the second light baffle 222b and/or is detected by the photosensor 228. In these and other embodiments, the first light baffle 222a and/or the second light baffle 222b can include lightened (e.g., white) or reflective sidewalls. The lightened or reflective sidewalls can facilitate reflection of light that is emitted from the light source 225 off of the common optical axis and/or that is reflected from the diaphragm 213 off of the common optical axis. Stated another way, the lightened or reflective sidewalls of the first light baffle 222a and/or the second light baffle 222b can increase, maximize, and enhance the likelihood that light projected off of the common optical axis is reflected off of the sidewalls of the first light baffle 222a, is reflected off of the diaphragm 213, is reflected off of the sidewalls of the second light baffle 222b, and/or is detected by the photosensor 228. As a specific example, the first light baffle 222a can include lightened or reflective sidewalls (e.g., to increase the amount of light that reaches and/or is reflected off of the diaphragm 213), and the second light baffle 222b can include darkened sidewalls (e.g., to reduce the likelihood that light reflected off of the diaphragm 213 off of the common optical axis strikes and/or is detected by the photosensor 228). In other embodiments, the first light baffle 222a and/or the second light baffle 222b can be omitted, and light can intrinsically be directed from the light source 225 to the diaphragm 213 and/or from the diaphragm 213 to the photosensor 228 along the common optical axis. In some embodiments, the light source 225 and/or the light baffles 222 can be selected to reduce or enhance an effect in which an intensity of light emitted from the light source 225 is at a maximum along its central axis and gradually decreases away from that axis.
To obtain accurate pressure measurements, the pressure sensor 203 can include one or more electronic circuits (not shown) that are configured to supply a constant current to the light source 225 (e.g., to maintain a stable light output over time) and/or a constant voltage to the photosensor 228 (e.g., to maintain a stable light sensitivity over time). Current and voltage can be dependent upon a number of factors, including temperature. Thus, the pressure sensor 203 can include one or more temperature sensors 226 in some embodiments to help compensate for fluctuations in temperature of various components of the pressure sensor 203 and/or for fluctuations in temperature of the ambient atmosphere surrounding components of the pressure sensor 203 over time. For example, in the embodiment illustrated in
Referring now to the diaphragm 213, the diaphragm 213 can be aligned with the pressure sensor 203 (e.g., using the mount 224 or another mount or holder of the pressure sensor 203 of the APD system). For example, the diaphragm 213 can be positioned, centered, and/or held beneath the opening 221 and/or another opening of the mount 224. In these and other embodiments, the diaphragm 213 can be positioned, centered, and/or held along the common optical axis described above. In these and still other embodiment, the diaphragm 213 can be positioned, centered, and/or held at a fixed distance from the opening 221, the light source 225, and/or the photosensor 228.
As shown in
In some embodiments, the outer surface 213a of the diaphragm 213 can include a specular (e.g., mirror-like) reflector 215. For example, the outer surface 213a can include a polished or plated metal or metallic coating disposed on a smooth polymer substrate. The metallic coating can be aluminized PET (also known as reflective Mylar) or another metallic coating. As another example, the outer surface 213a can include a thin, flexible reflective foil or aluminum tape applied to a thicker and/or stiffer diaphragm substrate. In some embodiments, the reflector 215 can cover all of the outer surface 213a of the diaphragm 213. In other embodiments, the reflector 215 can cover a subset (e.g., a majority, just a central area, etc.) of the outer surface 213a of the diaphragm 213.
The diaphragm 213 can be attached, affixed, and/or integrated with a portion of a disposable set, such as the disposable set 107 of
The rim structure 311 and/or the diaphragm 213 define (at least in part) a cavity 316. The cavity 316 can be rigid (e.g., at least along the portions corresponding to the rim structure 311). Additionally, or alternatively, the cavity 316 can be closed (e.g., hermetically sealed) by the rim structure 311 and/or the diaphragm 213 except for the port 312. The port 312 can fluidly connect the cavity 316 to fluid lines (not shown) or other portions of the disposable set. In these embodiments, as fluid flows through the disposable set, the fluid can enter the cavity 316 via the port 312 and exert a force on the diaphragm 213. Although shown within only one port 312 in
The diaphragm 213 can be a rigid, semi-rigid, or semi-flexible structure. In some embodiments, a positive internal pressure within the cavity 316 (relative to external pressure) will cause the diaphragm 213 to deform outwardly while a negative internal pressure within the cavity 316 (relative to external pressure) will cause the diaphragm 213 to deform inwardly.
In
In
As discussed above, fluid enters the cavity 316 of the portion 207 of the disposable set via the port 312 and exerts a force against the diaphragm 213. The force is related to a pressure of the fluid within the cavity 316. Thus, when fluid pressure is positive, the fluid exerts a force that causes the diaphragm 213 to deform outwardly. When fluid pressure is negative, the fluid exerts a force that causes the diaphragm 213 to deform inwardly. As the diaphragm 213 deforms inwardly or outwardly, an amount of light (a) emitted from the light source 225 (
In some embodiments, the portion 307 of the disposable set can be a portion of a damping device (e.g., the damping device 102 of
Referring first to
In some embodiments, the area of the light 437 is limited by intrinsic directionality of the light source 225 and/or by use of the first light baffle 222a (
As the light 437 is emitted from the light source 225, the light 437 begins to diverge. The light 437 continues to diverge after it is reflected off of the diaphragm 213, and some of the light 437 can be blocked, absorbed, and/or reflected by the first and/or second light baffles 222 (
Referring now to
The collimating element 544 of the pressure sensor 503 can be a lens, a concave mirror, or another optical element. The collimating element 544 is configured to convert light 437 that is emitted from the light source 225 into collimated light 537. More specifically, the collimating element 544 can be positioned within the first light baffle 222a (
In these and other embodiments, the collimating element 544 and/or other components of the pressure sensor 503 and/or an APD system including the pressure sensor 503 can be configured (e.g., spaced, positioned, and/or oriented relative to one another) such that collimated light 537 that is reflected off of the diaphragm 213 and directed generally toward the photosensor(s) 228 can cover an area at the location of the photosensor(s) 228 that is larger (e.g., by a factor of 1.5, 2.0, or more) than a sensitive area of the photosensor(s) 228, even when the collimated light 537 is most concentrated (e.g., when diaphragm 213 is concave under negative pressures). Such an arrangement can prevent a loss of sensitivity to negative pressures as the diaphragm 213 forms a concave, converging mirror. Such an arrangement can additionally, or alternatively, decrease a sensitivity of the pressure sensor 503 to alignment of the light source 225, the diaphragm 213, and/or the photosensor(s) 228.
Referring to
In some embodiments, the collimated light 537 reflected off of the diaphragm 213 and toward the photosensor(s) 228 under no pressure (
In these and other embodiments, for a given range of pressures, variation in the amounts of the collimated light 537 that are detected by the photosensor(s) 228 in
As discussed above, the pressure sensor 503 can include a plurality of photosensors 228. For example, the pressure sensor 503 of
The first photosensor 228a can be positioned at a location generally similar to the photosensor 228 of
As shown in
Referring to
Referring to
The first photosensor 228a and the second photosensor 228b of the pressure sensor 503 can therefore be used to produce a differential output representing an amount of the collimated light 537 detected that varies with pressure applied to the diaphragm 213 by fluid in the cavity 316 (
In operation, the photosensor 628 is configured to receive a first portion 637a of light 637 emitted from the light source 225 that is not directed toward the diaphragm 213 while a second portion 637b of the light 637 is emitted from the light source 225 and directed toward the diaphragm 213. As such, the photosensor 628 can provide a measurement of the light 637 emitted from the light source 225 that is not dependent upon reflectance off of the diaphragm 213 (in contrast to the portion 638 of the light 637 detected by the photosensor(s) 228). The measurement captured by the photosensor 628 can be used to detect and/or compensate for variations in the light 637 emitted from the light source 225 that can occur due to variations in (a) voltage or current supplied to the light source 225, (b) a temperature of the light source 225, and/or (c) aging of the light source 225.
Referring to
The light 757 projected onto the photosensor(s) 228 can provide a measure of sensitivity of the photosensor(s) 228 that is not dependent upon reflectance off of the diaphragm 213 (in contrast to the portion 738 of the light 737 emitted by the light source 225 and detected by the photosensor(s) 228). The measure of sensitivity of the photosensor(s) 228 that is provided by the light 757 from the light source 725 can be used to detect and/or compensate for variations in the sensitivity of the photosensor(s) 228 that can occur due to variations in (a) voltage or current supplied to the photosensor(s) 228; (b) a temperature of the photosensor(s) 228, and/or (c) aging of the photosensor(s) 228.
Although various components of pressure sensors of the present technology are illustrated and described above in separate embodiments, any combination of these components can be employed in pressure sensors configured in accordance with various other embodiments of the present technology. For example, a pressure sensor of the present technology can include the light source 225 (
The method 860 begins at block 861 by aligning a disposable set with a pressure sensor. In some embodiments, aligning the disposable set with the pressure sensor can include aligning a diaphragm of portion of the disposable set with the pressure sensor. For example,
At block 862, the method 860 continues by irradiating or illuminating the diaphragm. Irradiating the diaphragm can include emitting light from the light source and/or directing the light (e.g., at a first angle and/or along a first axis) toward an outer surface and/or a reflector of the diaphragm. Irradiating the diaphragm can include shielding the light emitted from the light source from ambient light using a first light baffle. In these and other embodiments, irradiating the diaphragm includes absorbing, using the first light baffle, portions of the light emitted from the light source that diverge from the first axis. In these and still other embodiments, irradiating the diaphragm includes limiting an area of the light emitted from the light source using the first light baffle such that a portions of the light that exits the opening 221 primarily strikes a central region of the diaphragm corresponding at least in part to the reflector. Additionally, or alternatively, irradiating the diaphragm includes collimating the light emitted from the light source using a collimating element such that the diaphragm is illuminated or irradiated with collimated light.
Irradiating the diaphragm can include irradiating the diaphragm when no pressure (e.g., other than atmospheric pressure) is applied to the diaphragm or when a positive or negative pressure is applied to the diaphragm. For example, the method 860 can irradiate the diaphragm when no pressure is applied to the diaphragm to determine a zero-offset value for pressure calculations. As another example, the method 860 can irradiate the diaphragm when positive and/or negative test pressures are applied to the diaphragm to determine a relationship between an amount of light detected by one or more photosensors of the pressure sensor and pressures applied to the diaphragm. As still another example, the method 860 can irradiate the diaphragm to measure pressure of fluid within the cavity of the portion of the disposable set.
At block 863, the method 860 continues by capturing one or more pressure measurements. In some embodiments, capturing a pressure measurement includes reflecting light emitted from the light source (e.g., at a second angle and/or along a second axis) toward one or more photosensors. Reflecting the light can include reflecting the light using a reflector and/or an outer surface of the diaphragm. Capturing a pressure measurement can include shielding light reflected from the diaphragm from ambient light using a second light baffle. In these and other embodiments, capturing a pressure measurement includes absorbing, using the second light baffle, portions of the light reflected from the diaphragm that diverge from the second axis. In these and still other embodiments, capturing a pressure measurement includes limiting an area of the reflected light that enters and/or travels along the second light baffle.
Additionally, or alternatively, capturing a pressure measurement includes capturing one or more amounts of the reflected light using one or more photosensors. For example, capturing a pressure measurement can include using a single or only one photosensor to detect an amount of light reflected from the diaphragm. As another example, capturing a pressure measurement can include using multiple photosensors, such as a first photosensor and a second photosensor, to detect multiple amounts of light reflected from the diaphragm and/or to determine a differential signal of the amount of light reflected from the diaphragm. In these and other embodiments, capturing a pressure measurement includes capturing an analog signal corresponding to an amount of light reflected from the diaphragm and/or detected by a photosensor. In these and still other embodiments, capturing a pressure measurement includes (a) converting the analog signal into a digital output and/or (b) determining pressure based at least in part on the analog signal, the digital output, and/or a relationship between measurements captured by a photosensor and pressure applied to the diaphragm.
Capturing a pressure measurement can include detecting an amount of light reflected from the diaphragm when no pressure (e.g., other than atmospheric pressure) is applied to the diaphragm or when a positive or negative pressure is applied to the diaphragm. For example, the method 860 can detect an amount of light reflected from the diaphragm when no pressure is applied to the diaphragm to determine a zero-offset value for pressure calculations. As another example, the method 860 can detect an amount of light reflected from the diaphragm when positive and/or negative test pressures are applied to the diaphragm to determine a relationship between an amount of light detected by one or more photosensors of the pressure sensor and pressures applied to the diaphragm. As still another example, the method 860 can detect an amount of light reflected from the diaphragm to measure pressure of fluid within the cavity of the portion of the disposable set.
In these and other embodiments, capturing a pressure measurement can include compensating for effects due to temperature, variations in voltage or current, and/or aging. Compensating for the effects can include detecting multiple amounts of light reflected from the diaphragm using multiple photosensors, such as a first photosensor and a second photosensor (e.g., to determine a differential signal of the amount of light reflected from the diaphragm). In these and other embodiments, compensating for the effects can include capturing one or more temperature measurements using a temperature sensor, such as one or more temperature measurements of a light source and/or a photosensor. In these and still other embodiments, compensating for the effects can include detecting, using a photosensor, a first portion of light emitted from a light source but not directed toward the diaphragm while a second portion of the light is emitted from the light source and directed toward the diaphragm. Additionally, or alternatively, compensating for the effects can include projecting light from a light source directly (e.g., without reflecting the light off of the diaphragm) onto a photosensor configured to detect a portion of light reflected from the diaphragm. Compensating for the effects can include (a) providing similar or identical photosensors and/or light sources; (b) supplying multiple photosensors and/or multiple light sources power from a same power source and/or (b) positioning photosensors and/or light sources as close to one another as is practical.
At block 864, the method 860 continues by determining whether a fluid pressure measured by the pressure sensor is within a safe operating range. In some embodiments, the safe operating range can include fluid pressures at which there is little risk of patient harm or discomfort from pressure of the fluid as it is introduced into or is drained out of the patient. For example, a safe operating range can include pressures from about -1.5 kPa to about +1.5 kPa. If the method 860 determines that the fluid pressure measured by the pressure sensor is within the safe operating range, the method 860 can return to block 863 to capture a next pressure measurement of fluid within the cavity 316 of the portion 307 of the disposable set. On the other hand, if the method 860 determines that the fluid pressure measured by the pressure sensor exceeds or is below the safe operating range, the method 860 can proceed to block 865.
At block 865, the method 860 continues by interrupting the flow of fluid through the disposable set and/or taking one or more other remedial actions. In some embodiments, interrupting the flow of fluid can include interrupting a dialysis cycle. In these and other embodiments, the one or more other remedial actions can include bringing the fluid pressure to within the safe operating range (e.g., using a pump or damping device of the system). In these and still other embodiments, the one or more other remedial actions can include generating and/or triggering an alert (e.g., to the user or patient) that pressure of the fluid is outside of the safe operating range.
Although the steps of the method 860 are discussed and illustrated in a particular order, the method 860 illustrated in
Although not shown so as to avoid unnecessarily obscuring the description of the embodiments of the technology, any of the devices, systems, and methods described above can include and/or be performed by a computing device configured to direct and/or arrange components of the systems and/or to receive, arrange, store, analyze, and/or otherwise process data received, for example, from the APD system and/or other components of the APD system (e.g., from pressure sensors, one or more photosensors, temperature sensors etc.). As such, such a computing device includes the necessary hardware and corresponding computer-executable instructions to perform these tasks. More specifically, a computing device configured in accordance with an embodiment of the present technology can include a processor, a storage device, input/output device, one or more sensors, and/or any other suitable subsystems and/or components (e.g., displays, speakers, communication modules, etc.). The storage device can include a set of circuits or a network of storage components configured to retain information and provide access to the retained information. For example, the storage device can include volatile and/or non-volatile memory. As a more specific example, the storage device can include random access memory (RAM), magnetic disks or tapes, and/or flash memory.
The computing device can also include (e.g., non-transitory) computer readable media (e.g., the storage device, disk drives, and/or other storage media) including computer-executable instructions stored thereon that, when executed by the processor and/or computing device, cause the systems to perform one or more of the methods described herein. Moreover, the processor can be configured for performing or otherwise controlling steps, calculations, analysis, and any other functions associated with the methods described herein.
In some embodiments, the storage device can store one or more databases used to store data collected by the systems as well as data used to direct and/or adjust components of the systems. In one embodiment, for example, a database is an HTML file designed by the assignee of the present disclosure. In other embodiments, however, data is stored in other types of databases or data files.
One of ordinary skill in the art will understand that various components of the systems (e.g., the computing device) can be further divided into subcomponents, or that various components and functions of the systems may be combined and integrated. In addition, these components can communicate via wired and/or wireless communication, as well as by information contained in the storage media.
Several aspects of the present technology are set forth in the following examples. Although several aspects of the present technology are set forth in examples specifically directed to systems, methods, and computer-readable mediums; any of these aspects of the present technology can similarly be set forth in examples directed to any of systems, devices, methods, and/or computer-readable mediums in other embodiments.
1. An automated peritoneal dialysis (APD) system, comprising:
2. The APD system of example 1 wherein the disposable set further includes a reflector disposed on the outer surface of the diaphragm and configured to reflect the light.
3. The APD system of example 1 or example 2 wherein:
4. The APD system of any of examples 1-3 wherein:
5. The APD system of any of examples 1-4 wherein:
6. The APD system of any of examples 1-5 wherein:
7. The APD system of any of examples 1-6 wherein:
8. The APD system of any of examples 1-7 wherein:
9. A method of measuring pressure of fluid within a disposable set of an automated peritoneal dialysis (APD) system, the method comprising:
10. The method of example 9, further comprising aligning the outer surface of the diaphragm with the light source and the photosensor.
11. The method of example 9 or example 10 wherein:
12. The method of any of examples 9-11 further comprising determining a relationship between amounts of light measured by the photosensor and deformation of the diaphragm in response to forces applied against the diaphragm due to pressures of the fluid within the disposable set.
13. The method of any of examples 9-12 wherein:
14. The method of any of examples 9-13, further comprising determining the pressure of the fluid within the disposable set based at least in part on the amount of the light reflected off of the outer surface of the diaphragm and directed toward the photosensor.
15. The method of example 14, further comprising comparing the pressure of the fluid to a safe operating pressure range.
16. The method of example 15, further comprising interrupting flow of the fluid through the disposable set when the pressure of the fluid is outside of the safe operating pressure range.
17. The method of any of examples 9-16, further comprising capturing one or more temperature measurements of the light source or the photosensor.
18. The method of any of examples 9-17 wherein:
19. The method of any of examples 9-18 wherein:
20. The method of any of examples 9-19 wherein:
21. The method of any of examples 9-20 wherein:
22. The method of any of examples 9-21 wherein measuring the amount of the light includes compensating for effects due to temperature, aging, variations in voltage supplied to the photosensor, or variations in current supplied to the light source.
23. A non-transitory, computer-readable medium having instructions stored thereon that, when executed by one or more processors of an automated peritoneal dialysis (APD) system, cause the APD system to perform a method comprising:
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. To the extent any materials incorporated herein by reference conflict with the present disclosure, the present disclosure controls. Where the context permits, singular or plural terms can also include the plural or singular term, respectively. Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. As used herein, the phrase “and/or” as in “A and/or B” refers to A alone, B alone, and both A and B. Where the context permits, singular or plural terms can also include the plural or singular term, respectively. Additionally, the terms “comprising,” “including,” “having” and “with” are used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded.
Furthermore, as used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. Moreover, the terms “connect” and “couple” are used interchangeably herein and refer to both direct and indirect connections or couplings. For example, where the context permits, element A “connected” or “coupled” to element B can refer (i) to A directly “connected” or directly “coupled” to B and/or (ii) to A indirectly “connected” or indirectly “coupled” to B.
The above detailed descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments can perform steps in a different order. As another example, various components of the technology can be further divided into subcomponents, and/or various components and/or functions of the technology can be combined and/or integrated. Furthermore, although advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments can also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology.
It should also be noted that other embodiments in addition to those disclosed herein are within the scope of the present technology. For example, embodiments of the present technology can have different configurations, components, and/or procedures in addition to those shown or described herein. Moreover, a person of ordinary skill in the art will understand that these and other embodiments can be without several of the configurations, components, and/or procedures shown or described herein without deviating from the present technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
This application is a 371 U.S. National Phase of PCT/US2021/047010, filed Aug. 20, 2021, which claims the benefit of priority from U.S. Provisional Pat. Application No. 63/068,384, filed Aug. 21, 2020, both which are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/047010 | 8/20/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63068384 | Aug 2020 | US |
