Abstract:
Systems and techniques for draining body fluid from a patient. In one aspect, a device includes a body fluid inlet that is biasable to a negative pressure suitable for draining body fluid from a patient, a fine measurement chamber having a volume V 1  and being connectable to the body fluid inlet to receive the body fluid and serve as an initial repository therefor, wherein the fine measurement chamber comprises a fine measurement mechanism having a resolution R 1 , and a coarse measurement chamber having a volume V 2  and being connectable to and disconnectable from the fine measurement chamber via a valve to intermittently receive the body fluid and serve as a repository therefor, wherein the coarse measurement chamber comprises a coarse measurement mechanism having a resolution R 2 . Volume V 1  is less than volume V 2  and resolution R 1  is greater than resolution R 2.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Chinese Patent Application Serial No. 200610116637.2, filed Sep. 28, 2006, Chinese Patent Application Serial No. 200620046392.6, filed Sep. 28, 2006, Chinese Patent Application Serial No. 200710087607.8, filed Mar. 1, 2007, and Chinese Patent Application Serial No. 200720004736.1, filed Mar. 1, 2007, the contents of all of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    This disclosure relates to systems and techniques for draining body fluid from a patient, especially from the pleural cavity and/or pericardial cavity. 
         [0003]    One or more fluids can accumulate in a patient who is suffering from a medical condition. The accumulating fluids can include blood, lymph, and gas, as well as other fluids. The accumulation can result from acute events (such as trauma, chest surgery, or heart surgery) or chronic events (such as tuberculosis and pericarditis). The fluids can accumulate, e.g., in the pleural cavity and/or the pericardial cavity of a patient. A failure to drain such fluids can harm the patient and even lead to the death of the patient. 
         [0004]    The rate at which fluids accumulate in the pleural cavity and/or pericardial cavity of a patient is often indicative of the physiological condition of the patient. For example, a rapid accumulation of blood in the pleural cavity and/or pericardial cavity of a patient can indicate that the patient is bleeding internally and that hemostatia may be warranted. 
       SUMMARY 
       [0005]    This disclosure describes systems and techniques for draining body fluid from the pleural cavity and/or pericardial cavity of a patient. In one aspect, a device includes a body fluid inlet that is biasable to a negative pressure suitable for draining body fluid from a patient, a fine measurement chamber having a volume V 1  and being connectable to the body fluid inlet to receive the body fluid and serve as an initial repository therefor, wherein the fine measurement chamber comprises a fine measurement mechanism having a resolution R 1 , and a coarse measurement chamber having a volume V 2  and being connectable to and disconnectable from the fine measurement chamber via a valve to intermittently receive the body fluid and serve as a repository therefor, wherein the coarse measurement chamber comprises a coarse measurement mechanism having a resolution R 2 . Volume V 1  is less than volume V 2  and resolution R 1  is greater than resolution R 2 . 
         [0006]    This and other aspects can include one or more of the following features. The device can include a pressure regulator arranged to maintain a pressure differential between the fine measurement chamber and the coarse measurement chamber. The coarse measurement chamber can be connectable to the fine measurement chamber to transfer the body fluid received by the fine measurement chamber under the pressure differential. The valve can be connected to the bottom of the fine measurement chamber. 
         [0007]    The device can include a pressure balancing mechanism to compensate for a pressure change resulting from the transfer of the body fluid from the fine measurement chamber to the coarse measurement chamber. The device can include a manually operable member that is actuable to open the valve and transfer the body fluid from the fine measurement chamber to the coarse measurement chamber. 
         [0008]    In another aspect, a method includes draining body fluid from one or both of the pleural cavity and the pericardial cavity of a patient, accumulating the drained body fluid in a fine measurement chamber that includes a fine measurement mechanism having a resolution R 1 , and transferring intermittently the body fluid accumulated in the fine measurement chamber to a coarse measurement chamber having a resolution R 2 . Transferring the body fluid comprises resetting the body fluid level in the fine measurement chamber to a reproducible baseline. Resolution R 1  is greater than resolution R 2 . 
         [0009]    This and other aspects can include one or more of the following features. The body fluid can be reset to the reproducible baseline by emptying the fine measurement chamber of the body fluid. Transferring the body fluid intermittently can include triggering the transfer of the body fluid and/or opening a valve separating the fine measurement chamber and the coarse measurement chamber. Transferring the body fluid intermittently can also include closing a valve on a fluid flow path between the fine measurement chamber and the patient. A pressure change resulting from the transfer of the body fluid from the fine measurement chamber to the coarse measurement chamber can be compensated for. 
         [0010]    In another aspect, a method includes connecting a device for draining body fluid to one or both of the pleural cavity and the pericardial cavity of a patient, measuring a first amount of body fluid drained from the patient over a first time period using a fine measurement mechanism having a resolution R 1 , storing the first amount of body fluid in a chamber that includes a coarse measurement mechanism having a resolution R 2 , measuring a second amount of body fluid drained from the patient over a second time period using the fine measurement mechanism, storing the second amount of body fluid with the first amount of body fluid in the chamber that includes the coarse measurement mechanism, and measuring a third amount of body fluid drained from the patient over a third time period using the fine measurement mechanism. Resolution R 1  is greater than resolution R 2 . 
         [0011]    This and other aspects can include one or more of the following features. The first amount and the second amount can be stored by transferring the first amount and the second amount from a fine measurement chamber to the chamber. Transferring the first amount and the second amount can include resetting the body fluid level in the fine measurement chamber to a reproducible baseline and/or opening a valve to place the fine measurement chamber in communication with the chamber. Transferring the first amount and the second amount can also include transferring the first amount and the second amount by pressure-driving the first amount and the second amount. 
         [0012]    Transferring the first amount and the second amount can include ending communication between fine measurement chamber and the one or both of the pleural cavity and the pericardial cavity of the patient. 
         [0013]    These and other aspects can achieve one or more of the following advantages. Body fluid that is drained from the pleural cavity and/or pericardial cavity of a patient can initially be received in a fine measurement chamber. Relatively precise measurements of the amount of fluid drained from the patient can be made. Thereafter, the body fluid can be transferred by pressure-driving the body fluid from the fine measurement chamber into a larger coarse measurement chamber. For example, the body fluid can be transferred into the coarse measurement chamber after the passage of a convenient amount of time or as the fine measurement chamber begins to fill to capacity. Coarse measurements of the total amount of fluid drained from the pleural cavity and/or pericardial cavity of a patient can be made after transfer. 
         [0014]    The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
     
     
       DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  is a schematic representation of a system for draining fluid from a body. 
           [0016]      FIG. 2  is a view from the rear of a device that can be used in the system of  FIG. 1 . 
           [0017]      FIG. 3  is a view from above of the device of  FIG. 2 . 
           [0018]      FIG. 4  is a view from the front of the device of  FIG. 2 . 
           [0019]      FIG. 5  is an enlarged view of portions of the device of  FIG. 2 . 
           [0020]      FIG. 6  is a diagrammatic representation of multi-path valve of the device of  FIG. 2 . 
       
    
    
       [0021]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0022]      FIG. 1  is a schematic representation of a system  100  for draining fluid from a body. System  100  includes a coarse measurement chamber  105 , a fine measurement chamber  110 , a vacuum source  115 , a valve and regulator assembly  120 , and a fluid inlet  125 . Coarse measurement chamber  105  is a fluid vessel that includes one or more mechanisms for making relatively coarse measurements of fluid amounts. Fine measurement chamber  110  is a fluid vessel that includes one or more mechanisms for making relatively fine measurements of fluid amounts. Vacuum source  115  is a source of a vacuum, such as a vacuum pump. 
         [0023]    Valve and regulator assembly  120  is a collection of one or more valves and/or regulators that operatively interconnect coarse measurement chamber  105 , fine measurement chamber  110 , vacuum source  115  for draining fluid from a body over inlet  125 . In particular, valve and regulator assembly  120  can regulate pressure transmitted from vacuum source  115  so that fine measurement chamber  110  can be kept at a negative pressure suitable for draining fluid from a body (e.g., between negative 20-25 cm H 2 0) over fluid inlet  125 . Valve and regulator assembly  120  can also valve the pressure differential between coarse measurement chamber  105  and fine measurement chamber  110  so that, at times, fluid is transferred by pressure-driving the fluid from fine measurement chamber  110  into coarse measurement chamber  105 . 
         [0024]      FIG. 2  is a view from the rear and  FIG. 3  is a view from above of one implementation of a portion of system  100 , namely, a device  200 . Device  200  houses measurement chambers  105 ,  110  and valve and regulator assembly  120 , as discussed further below. Device  200  can be connected to a hard or soft vacuum generated by vacuum source  115  over a vacuum inlet  205 . 
         [0025]    As shown, device  200  is a generally rectangular apparatus that is portable by medical personnel and/or a patient using a handle  202 . Device  200  is mounted on a rotatable base  210  and can include one or more members for elevated mounting on a wall or a rack, such as a pair of hook assemblies  215 . Using rotatable base  210  and/or hook assemblies  215 , medical personnel can position device  200  appropriately relative to a patient. 
         [0026]    Device  200  includes a vent opening  220  and a pair of valves  225 ,  230  that can place interior portions of device  200  in communication with the external environment. In particular, valve  225  is a pressure release valve that is connected to fine measurement chamber  110  within device  200 . As discussed further below, pressure release valve  225  can act as an emergency pressure release and open to ensure that an excessive negative pressure is not applied to a patient over fluid inlet  125 . 
         [0027]    Valve  230  is an adjustable pressure regulator valve that is connected to a pressure regulator within device  200 . As discussed further below, pressure regulator valve  230  can be adjusted to regulate the pressure in a chamber inside device  200  for use in draining body fluid from the pleural cavity and/or pericardial cavity of a patient. 
         [0028]    Vent opening  220  vents a portion of the pressure regulator within device  200  that is connected to valve  230 . Vent opening  220  can be covered with a removable air filtering membrane to allow nearly atmospheric pressure air to enter device  200  and ensure that regulation of pressure differential between coarse measurement chamber  105  and fine measurement chamber  110  is appropriate. 
         [0029]    Device  200  also includes a valve knob  235 . Valve knob  235  is manually-operable to open and close a multi-path valve  240  within device  200  and place coarse measurement chamber  105  and fine measurement chamber  110  in communication. By actuating valve knob  235 , a human user can allow fluid collected in fine measurement chamber  110  to enter coarse measurement chamber  105 . 
         [0030]      FIG. 4  is a view from the front of device  200 . The front of device  200  is formed of an at least partially transparent sheet that allows the fluid contents of measurement chambers  105 ,  110  inside device  200  to be visible from outside of device  200 . 
         [0031]    In this regard, coarse measurement chamber  105  is labeled with one or more collections of relatively coarse graduations  405  for volume measurement of the fluid contents of coarse measurement chamber  105 . Fine measurement chamber  110  is labeled with one or more collections of relatively fine graduations  410  for volume measurement of the fluid contents of fine measurement chamber  110 . A user looking through the transparent front sheet of device  200  can compare fluid levels in one or more of chambers  105 ,  110  to graduations  405 ,  410  to determine an amount of fluid that has been drained from the pleural cavity and/or pericardial cavity of a patient. Coarse measurement chamber  105  has a larger volume than fine measurement chamber  110  and can act as a relatively long-term reservoir for body fluid drained from the pleural cavity and/or pericardial cavity. 
         [0032]    In the illustrated implementation, fine measurement chamber  110  is an assembly of measurement columns  415 ,  420  that are joined by a spill-over passage  425 . Measurement column  415  is in communication with fluid inlet  125  via a guide passage  430  to receive fluid as it is drained from a patient. Spill-over passage  425  is positioned to allow fluid accumulating measurement column  415  to spill-over into measurement column  420 . In some implementations, measurement column  420  can have the same diameter as measurement column  415  and can offer the same high (i.e., fine) resolution measurements of fluid volume. The arrangement of measurement columns  415 ,  420  and spill-over passage  425  allows a relatively large dynamic range of volumes to be measured at relatively high resolution. 
         [0033]    Guide passage  430  is a fluid channel that guides fluid from fluid inlet  125  into measurement column  415 , and hence into fine measurement chamber  110 . In some implementations, guide passage  430  can include an upward facing concavity  435  that is accessible from outside of device  200  via an access port  440 . Access port  440  can be a pressure-sealed port that allows a user to access fluid retained in upward facing concavity  435 . In particular, as fluid is guided along guide passage  430  from fluid inlet  125  into measurement column  415 , some portion of the fluid can be captured and retained in upward facing concavity  435 . Access port allows a user to retrieve this portion of the fluid, e.g., for clinical or diagnostic purposes. In some implementations, access port  440  is a hole that is stoppered with a rubber plug. 
         [0034]    Valve and regulator assembly  120  is also housed within device  200 . Valve and regulator assembly  120  includes a vacuum feed system, a pressure regulator system, and a fluid transfer system. The vacuum feed system is a collection of passages within device  200  for feeding a vacuum placed on vacuum inlet  205  to various locations within device  200 . The pressure regulator system regulates the pressure differential between coarse measurement chamber  105  and fine measurement chamber  110 . The fluid transfer system allows fluid to be drained from fine measurement chamber  110  into coarse measurement chamber  105 , as discussed further below. 
         [0035]    Portions of the vacuum feed system, the pressure regulator system, and the fluid transfer system of device  200  have enlarged in  FIG. 5 . As shown, the pressure regulator system includes a water infusion vent  505 , a water storage column  510 , and a pressure transmission channel  515 . Infusion vent  505  extends from a top end  522  to an aperture  520 . Top end  522  of water infusing vent  505  communicates with vent opening  220  and can be infused with liquid through vent opening  220 . Aperture  520  of water infusing vent  505  communicates with the bottom water storage column  510 . 
         [0036]    Water storage column  510  extends from aperture  520  up to a connection  525  with a first pressure balance column  530 . Pressure balance column  530  balances the pressure when fluid is transferred by pressure-driving the fluid from fine measurement chamber  110  into coarse measurement chamber  105 , as discussed further below. 
         [0037]    In some implementations, water storage column  510  can include a fill mark  445  and a baffle  450  along its height between aperture  520  and connection  525  of pressure balance column  530 . Fill mark  445  identifies a height to which water storage column  510  can initially be loaded with liquid so that fluid can be drained from a body into device  200  at an appropriate negative pressure, as discussed further below. Baffle  450  is generally horizontal and demarcates upper and lower portions of water storage column  510 . In particular, baffle  450  can aid medical personnel in distinguishing between venting gas that enters water storage column  510  by way of aperture  520  of water infusing vent  505  and gas drained from a patient that enters water storage column  510  by way of pressure transmission channel  515 . Fill mark  445  is generally positioned along water storage column  510  above baffle  450 . 
         [0038]    Pressure transmission channel  515  runs alongside a portion of water storage column  510  and extends between an upper inlet  460  and an outlet  455 . Upper inlet  460  places pressure transmission channel  515  in communication with an extent  535  of fine measurement chamber  110 . Outlet  455  is positioned above baffle  450  and places channel  515  in communication with water storage column  510 . Thus, channel  515  places fine measurement chamber  110  in communication with water storage column  510  for the transmission of a regulated pressure from water storage column  510  to fine measurement chamber  110 , as discussed further below. 
         [0039]    As discussed above, the vacuum feed system is a collection of passages for feeding a vacuum placed on vacuum inlet  205  to various locations within device  200 . In particular, the vacuum feed system includes a first vacuum feed  545  and a second vacuum feed  550 . Vacuum feed  545  is arranged to feed a vacuum placed on vacuum inlet  205  to a junction between pressure regulator valve  230  and water storage column  510 . The negative pressure at vacuum inlet  205  is decreased by first vacuum feed  545 , regulated by pressure regulator valve  230 , and transferred by second vacuum feed  550  to water storage column  510 . Vacuum feed  550  is arranged to feed a vacuum placed on vacuum inlet  205  to a junction between pressure regulator valve  230  and water storage column  510 . Pressure regulator valve  230  can regulates the pressure transferred by vacuum feed  550  to water storage column  510  so that water storage column  510  is maintained at a pressure that is suitable for draining body fluid from the pleural cavity and/or pericardial cavity, as discussed further below. 
         [0040]    As discussed above, the fluid transfer system allows fluid to be transferred from fine measurement chamber  110  into coarse measurement chamber  105 . In addition to multi-path valve  240 , the fluid transfer system includes a fluid transfer path  465  and a pair of pressure balance columns  530 ,  540 . 
         [0041]    Fluid transfer path  465  include a downwardly sloped component  470  and a generally vertical component  475 . Generally vertical component  475  extends from multi-path valve  240 , which is located at the base of fine measurement chamber  110 , upward to communicate with downwardly sloped component  470  at a position  475 . Downwardly sloped component  470  slopes downward from position  475  to enter coarse measurement chamber  105  at an inlet  480 . 
         [0042]    Pressure balance column  530  extends between connection  525  with water storage column  510  and multi-path valve  240 . Pressure balance column  540  between multi-path valve  240  a connection  535  with fine measurement chamber  110 . Multi-path valve  240  is operable to open and close connection between pressure balance columns  530 ,  540 . 
         [0043]      FIG. 6  is a diagrammatic representation of multi-path valve  240 . As discussed above, multi-path valve  240  can be actuated using valve knob  235 . Multi-path valve  240  is generally tubular in shape and extends longitudinally from valve knob  235  to a pivot  605 . A pair of longitudinal paths  610 ,  615  are defined adjacent to one another on a first side  620  of multi-path valve  240 . A collection of ridges  625 ,  630 ,  635  are oriented radially on a second side  640  of multi-path valve  240 . 
         [0044]    Pivot  605  can be compression fit within a hole on device  200  to position multi-path valve  240  in device  200  but yet allow rotation about an axis A. In particular, when properly positioned, multi-path valve  240  can be rotated to switch between an open and a closed position. In the open position, pressure balance columns  530 ,  540  are in communication via longitudinal path  610  and measurement columns  415 ,  420  are in communication with each other and with generally vertical component  475  of fluid transfer path  465  via longitudinal path  615 . In the closed position, communication between pressure balance columns  530 ,  540  is prevented by ridge  625 , communication between measurement columns  415 ,  420  is prevented by ridge  630 , and communication between measurement column  420  and generally vertical component  475  of fluid transfer path  465  is prevented by ridge  635 . In some implementations, communication can be prevented by the mating of ridges  625 ,  630 ,  635  with a polymeric or other sealing member. 
         [0045]    In operation, device  200  can be positioned relative to a patient and supported using base  210  and/or hook assemblies  215 . Water, saline solution, or other liquid can be poured into device  200  through vent opening  220 . This liquid will enter water infusing vent  505  and, via aperture  520 , water storage column  510 . When the water reaches fill mark  445  of water storage column  510 , the filling of device  200  can be halted. Vent opening  220  can then be covered with an air filtering membrane. 
         [0046]    A vacuum source  115  place a vacuum on vacuum inlet  205  of device  200  using, e.g., a valved tube that is initially closed. An end of a sterile chest tube that is connected to an initially closed valve can be placed in the pleural cavity and/or pericardial cavity of a patient. The other side of the valve can be connected to fluid inlet  125 . If necessary, pressure regulator valve  230  can be adjusted so that the pressure in fine measurement chamber  110  is appropriate for drawing body fluid from the pleural cavity and/or pericardial cavity. For example, the approximately pressure regulator valve  230  can be adjusted to provide a negative pressure of about 20 to 25 cm H 2 O in fine measurement chamber  110 . The vacuum provided by vacuum source  115  can be released into device  200 . 
         [0047]    The vacuum provided by vacuum source  115  is fed to coarse measurement chamber  105  via vacuum inlet  205  and to water storage column  510  via vacuum feed  545 , pressure regulator valve  230 , and vacuum feed  550 . The application of the vacuum regulated by pressure regulator valve  230  to water storage column  510  will cause the water level in water storage column  510  to rise above fill mark  445 , draining water infusing vent  505 . At some point, the water level in water infusing vent  505  will fall below the level of aperture  520  and atmospheric air will pass into water storage column  510  via vent opening  220  and water infusing vent  505 . This air will be visible to a user as bubbles that indicate to a user that the pressure in water storage column  510  is appropriate. In particular, water infusing vent  505 , water storage column  510 , and aperture  520  can be positioned and dimensioned so that a column of about 20-25 cm is maintained in water storage column  510 , or about 2-3 cm above outlet  455 . 
         [0048]    At this point, the initially closed valve on the chest tube can be opened. The regulated negative pressure in water storage column  510  is transmitted to extent  535  of fine measurement chamber  110  via pressure transmission channel  515 . Since measurement columns  415 ,  420  are in communication via spill-over passage  425 , the regulated negative pressure is transmitted to guide passage  430 , fluid inlet  125 , and ultimately to the pleural cavity and/or pericardial cavity of the patient. 
         [0049]    This regulated negative pressure will drain body fluid from the pleural cavity and/or pericardial cavity of the patient through fluid inlet  125  and guide passage  430  and into fine measurement chamber  110  where it is initially collected in measurement column  415 . With valve  240  in the closed position, body fluid accumulates in measurement column  415 . The amount of body fluid accumulated in measurement column  415  can be determined by comparing the body fluid level with relatively fine graduations  410 . At some point, the body fluid accumulated in measurement column  415  will rise to the level of spill-over passage  425 . Spill-over passage  425  allows the body fluid to spill over into measurement column  420 . The amount of body fluid accumulated in measurement column  420  can also be determined using relatively fine graduations  410 . 
         [0050]    In some implementations, medical personnel can sample the body fluid accumulating in fine measurement chamber  110  via access port  440 . For example, when access port  440  is a hole that is stoppered with a rubber plug, medical personnel can use a syringe or other needle to penetrate the plug and withdraw fluid. 
         [0051]    At some point, the fluid accumulating in fine measurement chamber  110  can be transferred to coarse measurement chamber  105 . This may be triggered, e.g., by the fluid accumulation in fine measurement chamber  110  approaching the capacity of fine measurement chamber  110  or the passage of a physiologically suitable measurement time. 
         [0052]    To transfer the accumulated body fluid from fine measurement chamber  110  to coarse measurement chamber  105 , the valve on the chest tube can be closed. Valve knob  235  can be actuated to rotate multi-path valve  240  from the closed position to the open position. As discussed above, in the open position, measurement columns  415 ,  420  are in communication with each other and with generally vertical component  475  of fluid transfer path  465  via longitudinal path  615 . Fluid transfer path  465  communicates with coarse measurement chamber  105  which is under vacuum via inlet  205 . Thus, the accumulated body fluid will be drawn from fine measurement chamber  110 , up generally vertical component  475  and down downwardly sloped component  470  of fluid transfer path  465  into coarse measurement chamber  105 . 
         [0053]    Moreover, as discussed above, rotation of multi-path valve  240  into the open position also places pressure balance columns  530 ,  540  in communication with each other via longitudinal path  610 . The transfer of fluid from fine measurement chamber  110  into coarse measurement chamber  105  draws air into pressure balance columns  530 ,  540  via water storage column  510 , water infusing vent  505 , and vent opening  220 . This allows fine measurement chamber  110  to be rapidly emptied of fluid so that subsequent measurements of fluid accumulation in fine measurement chamber  110  can begin from an easily reproducible baseline. 
         [0054]    Once fine measurement chamber  110  has been drained, valve knob  235  can be actuated to rotate multi-path valve  240  from the open position to the closed position. Communication between pressure balance columns  530 ,  540  cut off, as is communication between measurement columns  415 ,  420 , and generally vertical component  475  of fluid transfer path  465 . Moreover, any residual liquid in downwardly sloped component  470  of fluid transfer path  465  can drain, via gravity, into coarse measurement chamber  105  and the regulated negative pressure in water storage column  510  will be restored. 
         [0055]    At this point, the valve on the chest tube can be reopened and body fluid can again be drained from the pleural cavity and/or pericardial cavity of the patient through fluid inlet  125  and guide passage  430  and into fine measurement chamber  110 . 
         [0056]    In some implementations, graduations  410  of fine measurement chamber  110  can allow a user to measure volumes up to 100-200 ml with a resolution of ±5 ml and graduations  405  of coarse measurement chamber  105  can allow a user to measure volume up to 1000 ml-2000 ml with a resolution of ±10 ml-20 ml. 
         [0057]    A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, valve knob  235  is shown as a manually operated knob that actuates multi-path valve  240 . However, multi-path valve  240  can also be operated automatically and/or electronically. For example, device  200  can include a level sensor that triggers the opening and closing of multi-path valve  240 . As another example, fine measurement chamber  110  can be assembled from additional measurement columns that are joined by additional spill-over passages. 
         [0058]    As another example, the pressure regulator system can include a dye or other marker to color the liquid in water infusing vent  505  and water storage column  510  for easy identification by a user. 
         [0059]    As another example, other measurement mechanisms, including electronic and/or mass measurement mechanisms, can be used in coarse measurement chamber  105  and/or fine measurement chamber  110 . 
         [0060]    Accordingly, other implementations are within the scope of the following claims.