Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
  • F04B43/06—Pumps having fluid drive
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
  • A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
  • A61M5/142—Pressure infusion, e.g. using pumps
  • A61M5/145—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons
  • A61M5/148—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons flexible, e.g. independent bags
  • A61M5/1483—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons flexible, e.g. independent bags using flexible bags externally pressurised by fluid pressure
  • A61M5/1486—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons flexible, e.g. independent bags using flexible bags externally pressurised by fluid pressure the bags being substantially completely surrounded by fluid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
  • A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
  • A61M5/168—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body
  • A61M5/16804—Flow controllers
  • A61M5/16809—Flow controllers by repeated filling and emptying of an intermediate volume
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
  • A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
  • A61M5/168—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body
  • A61M5/16886—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body for measuring fluid flow rate, i.e. flowmeters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/08—Machines, pumps, or pumping installations having flexible working members having tubular flexible members
  • F04B43/10—Pumps having fluid drive
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3331—Pressure; Flow
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3368—Temperature

Definitions

• the present disclosure relates to the field of pumps, especially those used to accurately dispense medication.
• Two chamber pumps and related methods provide a platform for measuring flow rate in about real time without contacting the material being pumped.
• Pressure and optional temperature sensors disposed in a pressurized chamber allow for fluid delivery calculations after being calibrated or by knowing the initial volume of the fluid to be delivered.
• a device comprising a pressurizable first chamber, a second chamber for holding a fluid, a flow lumen disposed exterior to the first chamber and in fluid communication with the second chamber, at least one pressure sensor disposed in the first chamber, and a flow controller disposed along the flow lumen.
• a pressurized substance in the first chamber is able to cause a change of volume of the second chamber.
• a device comprising a pressurizable first chamber, a second chamber for holding a fluid, a flow lumen disposed at least partially exterior to the first chamber and in fluid communication with the second chamber, at least one pressure sensor disposed in the first chamber, a flow controller disposed along the flow lumen, and a microprocessor to compute at least flow rate of fluid transferred through the flow lumen from the second chamber.
• a pressurized substance in the first chamber is able to cause a change of volume of the second chamber by causing fluid to flow from the second chamber through the flow lumen and the microprocessor controls the flow controller.
• a method comprising providing a pump having: (a) a pressurizable first chamber, (b) a second chamber for holding a fluid, (c) at least one pressure sensor disposed in the first chamber, (d) a flow lumen in fluid communication with the second chamber, and (e) a flow controller.
• a pressurized substance in the first chamber is able to cause a change of volume of the second chamber.
• Figure 1 is a cross sectional view of an embodiment of the pumps of the present disclosure having rigid outer casings
• Figure 2 is a cross sectional view of an embodiment of the pumps of the present disclosure, where the outer casing of the pump is a collapsible bag;
• Figure 3 is a cross sectional view of an embodiment of the pumps of the present disclosure.
• the term "real time” shall be defined as the instantaneous state or lagging the instantaneous state by the time taken to compute a measurement describing the instantaneous state, provided the measurement computed reasonably approximates the instantaneous state at the beginning of the measurement process and the instantaneous state at the end of the measurement process.
• the present disclosure discloses a pump that is able to measure flow rates or adjust flow rates in about real time.
• the pumps of the present disclosure comprise two chambers with at least a pressure sensor disposed therein to measure pressures in a pressured chamber that drives flow of a fluid from a liquid chamber.
• Flow controllers are disposed as part of the pump to either prevent flow or regulate and ensure consistent flow rate.
• the operation of the pumps of the present disclosure maintain sterile conditions for the fluid flow from the pumps, while allowing for precise measurements for flow volumes without compromising sterility.
• pump 100 comprises first chamber 110 and second chamber 120.
• First chamber is a chamber that is pressurized such that the pressure in first chamber exceeds the pressure of second chamber. Consequently, when pump 100 is in an open state, flow of fluid contained in second chamber 120 is effected.
• Flow of fluid from second chamber is through flow lumen 130.
• Flow lumen may be surgical or medical tubing, pipes, and other similar devices designed for the flow of fluids from a source to a destination without appreciable loss of fluid.
• flow controller 140 may be disposed along flow lumen 130 to control flow.
• Control of flow may be an on/off type device, such as a clamp, whereby when flow controller is open flow is effected and when flow controller 140 is closed, flow is prevented.
• Flow controller 140 may also comprise, according to embodiments, a flow restrictor to ensure constant or predictable flow.
• flow controller 140 may comprise a plurality of flow restrictors, clamps, etc.
• Fill device 150 is disposed along flow lumen 130 and facilitates the filling of second chamber 120 with fluid.
• Fill device 150 may comprise a one-way valve, according to embodiments, whereby fluid is flowed through valve and into second chamber 120.
• Fill device 150 is a luer actuated port, according to embodiments.
• fill valve comprises a device for putting a prefilled second chamber 120, such as a typical intravenous bag, into first chamber 110 after which first chamber 110 is pressurized.
• first chamber 110 is a chamber that is able to be pressurized.
• first chamber 110 may be made from any suitable rigid material, for example polycarbonate, ABS, or polyethylene.
• first chamber 110 may be made from flexible materials, for example PVC, polyethylene, silicon, polyurethane, or various rubbers.
• first chamber 110 is sealed to prevent leakage of gas contained therein.
• first chamber 110 may have a valve for repressurization or adjustment of pressure, as desired.
• first chamber 110 comprises a bag-like or collapsible device.
• Pressure sensor 115 is disposed in first chamber 100 to measure pressure at predetermined intervals, as well as initial pressure readings to be used to determine flow rate.
• a temperature sensor may also be disposed in first chamber 100 to improve accuracy of flow measurement. Multiple pressure and temperature sensors may be used to more accurately determine pressure and temperature in first chamber no.
• Second chamber 120 comprises a collapsible chamber that holds a fluid without appreciable leakage. When flow controller is in a state whereby flow is effected, flow from second chamber is effected by the pressure differential between first chamber 110 and second chamber 120. Second chamber 120 may be made from PVC, polyisoprene, silicon, polyurethane, or other flexible materials.
• second chamber 120 may be defined by a collapsible or movable diaphragm 225. Rather than collapsing second chamber 120, the movable or collapsible diaphragm 125 is moved whereby flow is effected.
• acoustic sensors including a loud speaker and one or more microphones may be used to accurately determine the volume of first chamber 110, thereby allowing for calculation of the volume of second chamber 120.
• Acoustic volume determination technology is disclosed in U.S. Pat. Nos. 5,575,310 and 5,755,683, which are incorporated by reference; and U.S. Provisional Serial No. 60/789,243, which is incorporated by reference.
• volume is known the method for calculating volume as disclosed below may be used to determine the amount of flow material dispensed from second chamber 120, or the principles disclosed herein may be adapted as would be known and understood by a person of ordinary skill in the art.
• the calibration step determines the initial volume of second chamber 120 (V_»), which is necessary to determine flow rate, as described below using the ideal gas law.
• V_ the initial volume of second chamber 120
• the most simple method for the determination of V 2 is to know the volume of fluid put into second chamber 120. This is accomplished by injecting a known amount of fluid into second chamber 120 via fill device 150 or using a disposable second chamber 120 (i.e., an IV bag) holding a known volume.
• calibration may also be accomplished by calculating, using the ideal gas law, the volume of second chamber 120 from a known starting volume in an empty state. If second chamber 120 occupies a known empty volume, for example using the pump of FIG.
• second chamber 120 has three discrete states: empty, filled, and flowing.
• the empty state defines second chamber when the volume is 0 or a known empty volume.
• the filled state defines the second chamber when it is filled with fluid.
• the flowing state defines a plurality of volumes where
• V 2 fl 0W ing is representative of the state wherein fluid is being delivered from pump 100 to a patient, for example.
• V 2 fl 0 wing may also be used for calculations during the filling of second chamber 120 with fluid.
• flow is effected because the pressure of first chamber 110 exceeds the fluid pressure in second chamber 120. Accordingly, flow rate may be calculated with high precision and in about real time. Prior to determination of flow rate, the filled state of pump 100 must be measured.
• ⁇ t is the time interval over which AV 1 and AV 2 are measured.
• V 2 volume of second chamber
• changes in V 2 are measured indirectly from the changing volume of Vi.
• Measurements of the volume of V 1 are accomplished with pressure sensor and optional temperature sensor.
• first chamber 110 is sealed, k remains constant throughout the flow of fluid from second chamber 120. Additionally, pressure sensor and optional temperature sensor disposed in first chamber 110 allows for measurement of Ptfaied, Piflowing, Ttfuied, and T ⁇ wing. Finally, the filled volume ( V ⁇ iied) of second chamber 120 is known, which allows calculation of Veiled, and therefore calculation of V ⁇ wing.
• the following equation for first chamber 110 results:
• the filled state comprises the end state at each discrete time interval in which flow rate is measured.
• the filled state of the prior time interval may comprise the filled of the succeeding time interval, and so forth as shown as the alternative to equation (9a).
• ⁇ or At may represent the aggregate time from the start of flow of fluid from second chamber 120 to the time being measured or may be indicative of any arbitrary time interval after the start of flow of fluid from second chamber 120 to the time being measured.
• Vifiiied is unknown and must be calculated from the total volume of pump c and from knowing the filled volume (y 2 flned) of fluid put into second chamber 120:
• the total amount of volume flowed may be calculated using the equation, based on the proportionality of flow between first chamber 110 and second chamber 120:
• measurements of flow rate are taken at discrete time intervals. These time intervals may range from many measurements per second to measurements taken over the course of minutes, hours, or days, depending on the specific application. Accordingly, measuring flow rate provides about real-time feedback, which may be used to adjust flow rate. By coupling the measurement of flow rate to flow controllers, flow may be closely regulated. For example, if flow controller 140 comprises a clamp, then feedback system may open the clamp when additional flow of fluid is needed and close the clamp when too much flow has occurred. Thus, the combination of a flow controller and the about real-time flow measurement provides a platform to deliver measurably accurate volumes of a fluid.
• first chamber 110 may be made from expandable materials.
• first chamber 110 may be a disposable bag or similar flexible-type container such as an IV-type bag, that tend to expand or contract depending on the pressure within the first chamber.
• first chamber 110 may be a disposable bag or similar flexible-type container such as an IV-type bag, that tend to expand or contract depending on the pressure within the first chamber.
• first chamber 110 is designed and made to have a known volume in this initial state. As pressure increases, the calculated additional volume due to expansion of first chamber 110 may be added to the initial volume to derive an accurate value of Vi.
• first chamber 110 is decreased and the pressure within first chamber 110 increases.
• first chamber 110 is made from non-rigid materials there will be predictable expansion of the dimensions of first chamber 110, with increased resulting volume.
• the pressure of first chamber is measured and volume is calculated as described previously, taking into account the incremental volume increase or decrease of first chamber 110 observed due to elasticity of material from which first chamber 110 is made.
• a method for accounting for the change in Vi due to expansion or contraction of first chamber 110 is to lookup the approximate change in volume of first chamber 110 as pressure within first chamber 110 increases or decreases in a lookup table.
• the lookup table is based upon averaged value for a plurality of the same first chamber 110 having the same dimensional parameters and will provide a reasonably approximate factor to add or subtract to Vi at a plurality of given measured pressures.
• vf be the supplemental volume of first chamber as first chamber 110 expands or contracts.
• the volume of first chamber no plus the volume of second chamber 120 is constant, as expressed in equation (4).
• first chamber no is made from expandable materials, however, a factor must be added to c denoting the added or lost volume occurring due to expansion or contraction of the first chamber no.
• volume of Fi may be calculated as:
• V x c+ V x E -V 2 . (l8)
• equation (16) is modified to account for the expanded first chamber no:
• V ⁇ may be calculated if the modulus of elasticity is known or may be simply recorded as a set of values within a table for quick lookup, especially in situations where a microprocessor is not designed to perform series of complex calculations or where power consumption is an issue.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Animal Behavior & Ethology (AREA)
• Veterinary Medicine (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Hematology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Vascular Medicine (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Anesthesiology (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• External Artificial Organs (AREA)
• Measuring Volume Flow (AREA)
• Infusion, Injection, And Reservoir Apparatuses (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40899426

Family Applications (1)

Country Status (3)

Families Citing this family (18)

Family Cites Families (45)

• 2008
  • 2008-01-25 US US12/020,498 patent/US20090191067A1/en not_active Abandoned
• 2009
  • 2009-01-23 EP EP09704892A patent/EP2242421A4/de not_active Withdrawn
  • 2009-01-23 WO PCT/US2009/031906 patent/WO2009094590A2/en not_active Ceased

Also Published As

Similar Documents

Legal Events