Patent Publication Number: US-2022233763-A1

Title: Peristaltic pump with constant biasing force

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application 63/142,916, filed Jan. 28, 2021, the entire disclosure of which is incorporated herein by this reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure generally relates to pumps, and, in particular, to peristaltic pumps. 
     BACKGROUND 
     Patients in hospitals often receive medications and medical fluids (e.g., a saline solution or a liquid medication) via infusion using an intravenous (“IV”) pump. In some applications, an IV pump uses peristaltic manipulation of a segment of tubing of an IV set to create the flow of medical fluid to the patient. 
     SUMMARY 
     The disclosed subject matter relates to peristaltic pumps. In certain embodiments, a peristaltic pump includes a plunger movable to selectively engage a pumping volume of a tubing segment to expand the pumping volume to draw fluid flow into the pumping volume and to contract the pumping volume to conduct fluid flow from the pumping volume; a first biasing member configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment during the expansion of the pumping volume; and a second biasing member configured to urge the plunger toward the tubing segment to contract the pumping volume. 
     In certain embodiments, a peristaltic pump includes a plunger movable to selectively engage a pumping volume of a tubing segment; a camshaft comprising a plunger cam lobe, wherein the plunger cam lobe is configured to move the plunger between an expansion position to draw fluid flow into the pumping volume and a contraction position to conduct fluid flow from the pumping volume; and a first biasing member configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment during the expansion of the pumping volume. 
     In certain embodiments, a method is disclosed and comprises expanding a peristaltic pumping volume of a tubing segment; and urging a plunger toward the tubing segment to maintain contact with the tubing segment during the expansion of the pumping volume with a first force. 
     It is understood that various configurations of the subject technology will become readily apparent to those skilled in the art from the disclosure, wherein various configurations of the subject technology are shown and described by way of illustration. As will be realized, the subject technology is capable of other and different configurations and its several details are capable of modification in various other respects, all without departing from the scope of the subject technology. Accordingly, the summary, drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed embodiments and together with the description serve to explain the principles of the disclosed embodiments. In the drawings: 
         FIG. 1  depicts a patient receiving an infusion of a medical fluid using an IV pump. 
         FIG. 2A  is a perspective view of a peristaltic pump, in accordance with various aspects of the present disclosure. 
         FIG. 2B  is a simplified view of the peristaltic pump of  FIG. 2A . 
         FIG. 3  is an exploded view of components of the peristaltic pump of  FIG. 2A . 
         FIG. 4A  is an illustration of the peristaltic pump of  FIG. 2A  in a filling phase, in accordance with various aspects of the present disclosure. 
         FIG. 4B  is an illustration of the peristaltic pump of  FIG. 2A  in a delivery phase, in accordance with various aspects of the present disclosure. 
         FIG. 4C  is an illustration of the peristaltic pump of  FIG. 2A  in a delivered position, in accordance with various aspects of the present disclosure. 
         FIG. 5A  is a simplified perspective view of a peristaltic pump, in accordance with various aspects of the present disclosure. 
         FIG. 5B  is a top view of the peristaltic pump of  FIG. 5A . 
         FIG. 5C  is a back view of the peristaltic pump of  FIG. 5A . 
         FIG. 6  is an exploded view of components of the peristaltic pump of  FIG. 5A . 
         FIG. 7A  is an illustration of the peristaltic pump of  FIG. 5A  in a filling phase, in accordance with various aspects of the present disclosure. 
         FIG. 7B  is an illustration of the peristaltic pump of  FIG. 5A  in an initial position, in accordance with various aspects of the present disclosure. 
         FIG. 7C  is an illustration of the peristaltic pump of  FIG. 5A  in a delivery phase, in accordance with various aspects of the present disclosure. 
         FIG. 7D  is an illustration of the peristaltic pump of  FIG. 5A  in a delivered position, in accordance with various aspects of the present disclosure. 
         FIG. 8A  is a simplified perspective view of a peristaltic pump, in accordance with various aspects of the present disclosure. 
         FIG. 8B  is a top view of the peristaltic pump of  FIG. 8A . 
         FIG. 8C  is a back view of the peristaltic pump of  FIG. 8A . 
         FIG. 9  is an exploded view of components of the peristaltic pump of  FIG. 8A . 
         FIG. 10A  is an illustration of the peristaltic pump of  FIG. 8A  in a filling phase, in accordance with various aspects of the present disclosure. 
         FIG. 10B  is an illustration of the peristaltic pump of  FIG. 8A  in an initial position, in accordance with various aspects of the present disclosure. 
         FIG. 10C  is an illustration of the peristaltic pump of  FIG. 8A  in a delivery phase, in accordance with various aspects of the present disclosure. 
         FIG. 10D  is an illustration of the peristaltic pump of  FIG. 8A  in a delivered position, in accordance with various aspects of the present disclosure. 
         FIG. 11A  is a perspective view of a peristaltic pump, in accordance with various aspects of the present disclosure. 
         FIG. 11B  is a simplified view of the peristaltic pump of  FIG. 11A . 
         FIG. 12  is a perspective view of the feeler pin of the peristaltic pump of  FIG. 11A . 
         FIG. 13A  is an illustration of the peristaltic pump of  FIG. 11A  in a filling phase, in accordance with various aspects of the present disclosure. 
         FIG. 13B  is an illustration of the peristaltic pump of  FIG. 11A  in a delivery phase, in accordance with various aspects of the present disclosure. 
         FIG. 13C  is an illustration of the peristaltic pump of  FIG. 11A  in a delivered position, in accordance with various aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be apparent to those skilled in the art that the subject technology may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. Like components are labeled with identical element numbers for ease of understanding. Reference numbers may have letter suffixes appended to indicate separate instances of a common element while being referred to generically by the same number without a suffix letter. 
     While the following description is directed to administration of medical fluid by utilizing the disclosed peristaltic pumps, it is to be understood that this description is only an example of usage and does not limit the scope of the claims. Various aspects of the disclosed peristaltic pumps may be used in any application where it is desirable to administer the flow of fluid. 
       FIG. 1  depicts a patient  5  receiving an infusion of a medical fluid using an IV pump  30 . In the depicted example, the IV pump  30  is delivering a medical fluid from a fluid container  36  to the patient  5 . A fluid container  36  is hung at or above the patient&#39;s head and connected via an IV set  20  to the IV pump module  34  and then to the patient  5 . In some embodiments, the IV pump  30  includes a control unit  32  and a pumping module  34 . 
     The pumping module  34  can include a peristaltic pump to administer the medical fluid from the fluid container  36  to the patient  5 . 
     During operation of the peristaltic pump, it may be desirable to monitor the volume pumped by the peristaltic pump. In some applications, the peristaltic pump can include a measurement phase between a refill phase and a delivery phase. 
     The disclosed peristaltic pump can incorporate various measurement mechanisms to allow for monitoring the volume pumped by the peristaltic pump. The disclosed peristaltic pump can include feeler mechanisms, biasing members with various levels of force, and/or split plungers. By utilizing the measurement mechanisms disclosed herein, the peristaltic pump can allow for monitoring without a dedicated measurement phase and/or without generating high internal pressures. 
     The disclosed peristaltic pump overcomes several challenges discovered with respect to certain measurement approaches utilized with peristaltic pumps. One challenge with certain measurement approaches is that during a dedicated measurement phase, a plunger may apply a large force to a fluid volume confined between an upper valve and a lower valve to measure the fluid volume, pressurizing the fluid volume. Accordingly, the upper valve and the lower valve may apply a large force to the tubing that contains the pressurized fluid volume during measurement, which may damage or cause wear to the tubing. Another challenge with certain measurement approaches is that flow may be discontinued during a dedicated measurement phase, promoting out-gassing of dissolved gases in an infusate. Because damage or wear to the tubing can result in tubing material particulate to dislodge from the tubing and enter a patient&#39;s bloodstream and out-gassing of dissolved gases can cause embolisms in a patient, it is advantageous to provide measurement mechanisms that allow for measurement of a fluid volume without a dedicated measurement phase and/or without generating high internal pressures. The disclosed peristaltic pumps provide for measurement of a fluid volume without a dedicated measurement phase and/or without generating high internal pressures during a measurement phase. 
     Examples of peristaltic pumps that allow for measurement of a fluid volume without a dedicated measurement phase and/or without generating high internal pressures are now described. 
       FIG. 2A  is a perspective view of a peristaltic pump  100 , in accordance with various aspects of the present disclosure.  FIG. 2B  is a simplified view of the peristaltic pump  100  of  FIG. 2A . In the depicted example, the peristaltic pump  100  can peristaltically manipulate tubing to create the flow of medical fluid to the patient. In some embodiments, an upstream portion of the tubing is in fluid communication with a source of medical fluid, such as an IV bag or other medical fluid container, and the downstream portion of the tubing is in fluid communication with IV tubing to the patient. In some embodiments, the peristaltic pump  100  repeatedly cycles between a filling phase and a delivery phase to administer fluid to the patient. As described herein, the peristaltic pump  100  allows for volume measurements without requiring a dedicated measurement phase. 
     In the depicted example, the peristaltic pump  100  includes a plunger  110 , an upstream occluder or valve  120 , and a downstream occluder or valve  130 , each configured to contact and manipulate the tubing to deliver fluid from a fluid source to the patient. In some embodiments, the plunger  110 , the upstream valve  120 , and the downstream valve  130  can move in coordinated, sequential steps to pump fluid through the tubing. The tubing can be formed from a mechanically resilient material. The tubing can be supported by a backer  180  as the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  contact and manipulate the tubing. 
     As described herein, the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  can be moved by one or more actuators. The movement of actuators that control the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  can be coordinated, or otherwise sequenced. In the depicted example, the movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  is cyclical. 
       FIG. 3  is an exploded view of components of the peristaltic pump  100  of  FIG. 2A . With reference to  FIGS. 2A-3 , the peristaltic pump  100  can include a camshaft  150  to actuate the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . In the depicted example, the camshaft  150  includes one or more cam lobes, such as a plunger cam lobe  154 , an upstream valve cam lobe  152 , and/or a downstream valve cam lobe  156 . 
     As described herein, the geometry of the respective cam lobes can be shaped or modified to allow for a desired actuation or movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . For example, portions of a cam lobe with a larger radius can allow for the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  to open or lift further from the tubing and/or backer  180  while portions of a cam lobe with a smaller radius can allow the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  to closer or otherwise be urged toward the tubing and/or backing. 
     In some embodiments, the cam lobes of the camshaft  150  actuate one or more rockers to control the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . As can be appreciated, the geometry of the rockers described herein can be configured to provide a desired actuation ratio between the movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  and the geometry of the plunger cam lobe  154 , upstream valve cam lobe  152 , and/or the downstream valve cam lobe  156 , respectively. As described herein, certain rockers, such as the second plunger valve rocker  111   b  may move independently or may otherwise not be directly actuated by the camshaft  150 . The first plunger valve rocker  111   a , the second plunger valve rocker  111   b , the upstream valve rocker  121 , and/or the downstream valve rocker  131  can each rotate or pivot about a pivot shaft  170 . 
     In the depicted example, biasing members, such as springs can urge the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  toward the tubing and/or the backer  180 . In some embodiments, biasing members can act upon the rockers to urge the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  toward the tubing and/or the backer  180 . During operation, actuation of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  by the camshaft can overcome the biasing force applied by the biasing members to lift or otherwise actuate the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . 
     Further, the arrangement or phasing of the cam lobes about the camshaft  150  can be modified to provide a desired sequence of actuation or movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  as the camshaft  150  is rotated. For example, the plunger cam lobe  154 , the upstream valve cam lobe  152 , and/or the downstream valve cam lobe  156  can each have a cam profile and/or a relative arrangement that eliminates or otherwise does not include a dedicated measurement phase where the plunger  110  is actuated against a pumping volume of the tubing closed by the upstream valve  120  and the downstream valve  130 . 
     In the depicted example, the peristaltic pump  100  includes a split rocker arrangement with a first plunger valve rocker  111   a  directly coupled to the plunger  110  and a second plunger valve rocker  111   b  configured to act upon the first plunger valve rocker  111   a . In some embodiments, the first plunger valve rocker  111   a  is spaced apart, decoupled, not aligned, or otherwise not directly actuated by the plunger cam lobe  154 . As can be appreciated, the first plunger valve rocker  111   a  and therefore the plunger  110  may be independently moved or actuated separate from the actuation of the plunger cam lobe  154 . 
     In the depicted example, a first plunger biasing member  164   a  can act upon the first plunger valve rocker  111   a  to urge the plunger  110  toward the tubing and/or the backer  180 . As can be appreciated, the biasing force applied by the first plunger biasing member  164   a  to the first plunger valve rocker  111   a  and the plunger  110  can be a constant or chronic force that is independent of the rotation of the camshaft  150 . During operation, the arrangement of the first plunger valve rocker  111   a  and the first plunger biasing member  164   a  can allow the plunger  110  to maintain contact with the tubing. As can be appreciated, the force applied by the first plunger biasing member  164   a  can be sufficient for the plunger  110  to maintain contact with the tubing without damaging the tubing. 
     In the depicted example, the position of the plunger  110  can be used to determine the volume of fluid administered by the peristaltic pump  100 . During operation, the height of the plunger  110  can be used to determine the height of the pumping volume within the tubing, which can be used to determine the volume of fluid administered by the peristaltic pump  100 . Advantageously, the arrangement of the first plunger biasing member  164   a  and the first plunger valve rocker  111   a  allows for the plunger  110  to permit volume measurements without exerting excess force or requiring a dedicated measurement phase. 
     In the depicted example, the second plunger valve rocker  111   b  is aligned, positioned, or otherwise configured to be actuated by the plunger cam lobe  154 . During operation, a portion of the second plunger valve rocker  111   b  can engage or slide along the cam profile of the plunger cam lobe  154  to translate the geometry of the cam profile into movement of the second plunger valve rocker  111   b . In some embodiments, during certain movements (e.g., during a delivery phase of operation) the second plunger valve rocker  111   b  can engage with the first plunger valve rocker  111   a  to move the plunger  110  relative to the tubing in response to actuation from the plunger cam lobe  154 . 
     In the depicted example, a second plunger biasing member  164   b  can act upon the second plunger valve rocker  111   b  to urge the second plunger valve rocker  111   b  toward the first plunger valve rocker  111   a . During certain portions of operation (e.g., the delivery phase of operation) the second plunger biasing member  164   b  can force the second plunger valve rocker  111   b  to engage with the first plunger valve rocker  111   a  and urge the plunger  110  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the second plunger valve rocker  111   b  by the rotation of the plunger cam lobe  154  can overcome the biasing force to disengage the second plunger valve rocker  111   b  from the first plunger valve rocker  111   a . Accordingly, the biasing force applied by the second plunger biasing member  164   b  to the first plunger valve rocker  111   a  and/or the plunger  110  can vary in response to the actuation of the second plunger valve rocker  111   b  by the rotation of the plunger cam lobe  154 . During operation, the arrangement of the second plunger valve rocker  111   b  and the second plunger biasing member  164   b  relative to the first plunger valve rocker  111   a  and the first plunger biasing member  164   a  allows the peristaltic pump  100  to apply additional force to the plunger during certain portions of operation (e.g., the delivery phase) while allowing the first plunger biasing member  164   a  to maintain a chronic biasing force against the tubing. In some embodiments, the force applied by the second plunger biasing member  164   b  is higher than the biasing force applied by the first plunger biasing member  164   a . Optionally, the force applied by the second plunger biasing member  164   b  is sufficient to allow fluid delivery. In some embodiments, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively provide sufficient force to allow for fluid delivery. 
     In some embodiments, an upstream valve rocker  121  is coupled to the upstream valve  120  and can move the upstream valve  120  in response to actuation from the upstream valve cam lobe  152 . During operation, a portion of the upstream valve rocker  121  can engage or slide along the cam profile of the upstream valve cam lobe  152  to translate the geometry of the cam profile into movement of the upstream valve  120  relative to the tubing. 
     As illustrated, an upstream valve biasing member  162  can act upon the upstream valve rocker  121  to urge the upstream valve  120  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the upstream valve rocker  121  by the rotation of the upstream valve cam lobe  152  can overcome the biasing force to lift or otherwise actuate the upstream valve  120 . 
     Similarly, a downstream valve rocker  131  is coupled to the downstream valve  130  and can move the downstream valve  130  in response to actuation from the downstream valve cam lobe  156 . During operation, a portion of the downstream valve rocker  131  can engage or slide along the cam profile of the downstream valve cam lobe  156  to translate the geometry of the cam profile into movement of the downstream valve  130  relative to the tubing. 
     Similarly, a downstream valve biasing member  166  can act upon the downstream valve rocker  131  to urge the downstream valve  130  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the downstream valve rocker  131  by the rotation of the downstream valve cam lobe  156  can overcome the biasing force to lift or otherwise actuate the downstream valve  130 . 
       FIG. 4A  is an illustration of the peristaltic pump  100  of  FIG. 2A  in a filling phase, in accordance with various aspects of the present disclosure. During operation, the tubing  102  draws in medical fluid  10  during the filling phase. As illustrated, the plunger  110  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the pumping volume  107  to an original or expanded state. 
     In the depicted example, the expansion of the pumping volume  107  draws in fluid into the pumping volume  107 . The mechanical resilience of the tubing  102  allows the tubing walls  104  to expand from a compressed state to an expanded state, expanding the pumping volume  107 . The rate at which the pumping volume  107  rebounds from a compressed state to an expanded state can determine the amount of fluid that can be drawn into the pumping volume  107  in a given period of time. 
     As illustrated, during the expansion of the pumping volume  107 , the downstream portion  108  of the tubing  102  is blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . 
     In the depicted example, the downstream valve  130  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  at the downstream portion  108  to occlude flow through the downstream portion  108  of the tubing  102 . The downstream valve  130  can include a beveled engagement portion to contact the tubing  102 . When engaged, the downstream valve  130  can prevent or restrict flow or fluid communication from the downstream portion  108  into the pumping volume  107 . 
     During the expansion of the pumping volume  107 , medical fluid  10  is drawn into pumping volume  107  from the upstream portion  106  of the tubing  102 . As illustrated, during the expansion of the pumping volume  107 , the upstream portion  106  of the tubing  102  is unobstructed by the upstream valve  120 , permitting medical fluid  10  into the pumping volume  107 . During operation, the upstream valve  120  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the upstream portion  106  to an original or expanded state. 
     In the depicted example, the expansion of the upstream portion  106  permits the flow of medical fluid  10  into the pumping volume  107 . The mechanical resilience of the tubing  102  allows the tubing walls  104  to expand from a compressed state to an expanded state, expanding the cross-sectional profile or flow area of the upstream portion  106 . The amount of medical fluid  10  drawn into the pumping volume  107  during the filling phase can be determined by the timing and sequence of the plunger  110 , the upstream valve  120 , a viscosity of the medical fluid  10 , and the mechanical properties of the tubing  102 . 
     Advantageously, and as described herein, the first plunger biasing member  164   a  can maintain a constant or chronic force to allow the plunger  110  to maintain contact with the tubing  102  during the filling phase to permit measurement of the pumping volume. In the depicted example, the force applied by the first plunger biasing member  164   a  can be sufficient to maintain contact with the tubing  102  while allowing for the pumping volume  107  to be filled. 
       FIG. 4B  is an illustration of the peristaltic pump  100  of  FIG. 2A  in a delivery phase, in accordance with various aspects of the present disclosure.  FIG. 4C  is an illustration of the peristaltic pump  100  of  FIG. 2A  in a delivered position, in accordance with various aspects of the present disclosure. With reference to  FIGS. 4B and 4C , the peristaltic pump  100  delivers medical fluid through a downstream portion  108  to a downstream location, such as a patient. As illustrated, the plunger  110  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  to compress the pumping volume  107  to a compressed or reduced state. 
     During operation, the compression of the pumping volume  107  expels or otherwise administers fluid from the pumping volume  107  to a downstream location. The rate of administration of the medical fluid can be controlled by the force and velocity of the plunger  110 . 
     As described herein, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively force the plunger  110  to compress the pumping volume  107  to a compressed or reduced state. In some embodiments, the second plunger biasing member  164   b  can force the plunger  110  to compress the pumping volume  107  to a compressed or reduced state without the cooperation of the first plunger biasing member  164   a.    
     During administration, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     In the depicted example, the upstream valve  120  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  at the upstream portion  106  to occlude flow through the upstream portion  106  of the tubing  102 . The upstream valve  120  can include a beveled engagement portion to contact the tubing  102 . When engaged, the upstream valve  120  can prevent or restrict flow or fluid communication between the upstream portion  106  and the pumping volume  107 . 
     During the compression of the pumping volume  107 , medical fluid is forced from the pumping volume  107  to a downstream location through the downstream portion  108  of the tubing  102 . As illustrated, during the compression of the pumping volume  107 , the downstream portion  108  of the tubing  102  is unobstructed by the downstream valve  130 , permitting medical fluid  10  to flow out of the tubing  102 . During operation, the downstream valve  130  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the downstream portion  108  to an original or expanded state. 
     In the depicted example, the expansion of the downstream portion  108  permits the flow of medical fluid  10  out of the pumping volume  107 . The mechanical resilience of the tubing  102  allows the tubing walls  104  to expand from a compressed state to an expanded state, expanding the cross-sectional profile or flow area of the downstream portion  108 . The rate at which the downstream portion  108  rebounds from a compressed state to an expanded state can limit the size of the flow area or opening out of the pumping volume  107 . Therefore, the rate at which the downstream portion  108  rebounds from a compressed state to an expanded state can limit or restrict the amount of fluid that can flow out of the pumping volume  107  in a given period of time. 
     The amount of medical fluid  10  administered from the pumping volume  107  during the delivery phase can be determined by the timing and sequence of the plunger  110 , the downstream valve  130  and the mechanical properties of the tubing  102 . 
       FIG. 5A  is a perspective view of a peristaltic pump  100 , in accordance with various aspects of the present disclosure.  FIG. 5B  is a simplified view of the peristaltic pump  100  of  FIG. 5A .  FIG. 5C  is a back view of the peristaltic pump  100  of  FIG. 5A .  FIG. 6  is an exploded view of components of the peristaltic pump  100  of  FIG. 5A . With reference to  FIGS. 5A-6 , the peristaltic pump  100  can independently control the operation of the first plunger valve rocker  111   a  and the second plunger valve rocker  111   b  to control the spring or biasing force applied to the plunger  110 . Advantageously, the peristaltic pump  100  can be configured to permit volume measurements without exerting excess force during a measurement phase. 
     As previously described, the peristaltic pump  100  can include a camshaft  150  to actuate the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . In the depicted example, the camshaft  150  includes one or more cam lobes, such as a first plunger cam lobe  154   a , a second plunger cam lobe  154   b , an upstream valve cam lobe  152 , and/or a downstream valve cam lobe  156 . 
     In the depicted example, the peristaltic pump  100  includes a split rocker arrangement with a first plunger valve rocker  111   a  directly coupled to the plunger  110  and a second plunger valve rocker  111   b  configured to act upon the first plunger valve rocker  111   a . In the depicted example, the first plunger valve rocker  111   a  is aligned, positioned, or otherwise configured to be actuated by the first plunger cam lobe  154   a . During operation, a portion of the first plunger valve rocker  111   a  can engage or slide along the cam profile of the first plunger cam lobe  154   a  to translate the geometry of the cam profile into movement of the first plunger valve rocker  111   a  and the plunger  110 . As can be appreciated, the first plunger valve rocker  111   a  and therefore the plunger  110  may be independently moved or actuated separate from the actuation of the second plunger valve rocker  111   b  during certain portions of operation (e.g., a measurement phase). 
     In the depicted example, a first plunger biasing member  164   a  can act upon the first plunger valve rocker  111   a  to urge the plunger  110  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the first plunger valve rocker  111   a  by the rotation of the first plunger cam lobe  154   a  can overcome the biasing force to lift or otherwise actuate the plunger  110  independent of the second plunger valve rocker  111   b . Therefore, the force applied to the plunger  110  can vary in response to the actuation of the first plunger valve rocker  111   a  by the rotation of the first plunger cam lobe  154   a.    
     During operation, the arrangement of the first plunger valve rocker  111   a , the first plunger cam lobe  154   a , and the first plunger biasing member  164   a  can allow the plunger  110  to contact the tubing during a measurement phase without administering the fluid within the pumping volume or damaging the tubing. 
     In the depicted example, the second plunger valve rocker  111   b  is aligned, positioned, or otherwise configured to be actuated by the second plunger cam lobe  154   b . During operation, a portion of the second plunger valve rocker  111   b  can engage or slide along the cam profile of the second plunger cam lobe  154   b  to translate the geometry of the cam profile into movement of the second plunger valve rocker  111   b . In some embodiments, during certain movements (e.g., during a delivery phase of operation) the second plunger valve rocker  111   b  can engage with the first plunger valve rocker  111   a  to move the plunger  110  relative to the tubing in response to actuation from the second plunger cam lobe  154   b.    
     In the depicted example, a second plunger biasing member  164   b  can act upon the second plunger valve rocker  111   b  to urge the second plunger valve rocker  111   b  toward the first plunger valve rocker  111   a . During certain portions of operation (e.g., the delivery phase of operation) the second plunger biasing member  164   b  can force the second plunger valve rocker  111   b  to engage with the first plunger valve rocker  111   a  and urge the plunger  110  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the second plunger valve rocker  111   b  by the rotation of the second plunger cam lobe  154   b  can overcome the biasing force to disengage the second plunger valve rocker  111   b  from the first plunger valve rocker  111   a . Accordingly, the biasing force applied by the second plunger biasing member  164   b  to the first plunger valve rocker  111   a  and/or the plunger  110  can vary in response to the actuation of the second plunger valve rocker  111   b  by the rotation of the second plunger cam lobe  154   b . During operation, the arrangement of the second plunger valve rocker  111   b  and the second plunger biasing member  164   b  relative to the first plunger valve rocker  111   a  and the first plunger biasing member  164   a  allows the peristaltic pump  100  to apply additional force to the plunger during certain portions of operation (e.g., the delivery phase) while allowing the a reduced force during other portions of operation (e.g., the measurement phase). In some embodiments, the force applied by the second plunger biasing member  164   b  is higher than the biasing force applied by the first plunger biasing member  164   a . Optionally, the force applied by the second plunger biasing member  164   b  is sufficient to allow fluid delivery. In some embodiments, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively provide sufficient force to allow for fluid delivery. 
     Further, the arrangement or phasing of the first plunger cam lobe  154   a  and the second plunger cam lobe  154   b  about the camshaft  150  can be modified to provide a desired sequence of actuation or movement of the first plunger valve rocker  111   a  and the second plunger valve rocker  111   b  as the camshaft  150  is rotated. For example, the cam lobes can each have a cam profile and/or a relative arrangement that includes a measurement phase that applies the plunger to the tubing with a reduced spring force. 
       FIG. 7A  is an illustration of the peristaltic pump  100  of  FIG. 5A  in a filling phase, in accordance with various aspects of the present disclosure. During operation, the tubing  102  draws in medical fluid  10  during the filling phase. As illustrated, the plunger  110  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the pumping volume  107  to an original or expanded state. 
     In the depicted example, the expansion of the pumping volume  107  draws in fluid into the pumping volume  107 . As illustrated, during the expansion of the pumping volume  107 , the downstream portion  108  of the tubing  102  is blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . 
     During the expansion of the pumping volume  107 , medical fluid  10  is drawn into pumping volume  107  from the upstream portion  106  of the tubing  102 . As illustrated, during the expansion of the pumping volume  107 , the upstream portion  106  of the tubing  102  is unobstructed by the upstream valve  120 , permitting medical fluid  10  into the pumping volume  107 . During operation, the upstream valve  120  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the upstream portion  106  to an original or expanded state. 
     In the depicted example, the expansion of the upstream portion  106  permits the flow of medical fluid  10  into the pumping volume  107 . Advantageously, and as described herein, the arrangement of the first plunger cam lobe  154   a  and the second plunger cam lobe  154   b  can prevent the first plunger biasing member  164   a  and the second plunger biasing member from applying force to the plunger  110  and/or the tubing  102  during the filling phase. 
       FIG. 7B  is an illustration of the peristaltic pump  100  of  FIG. 5A  in an initial or measurement position, in accordance with various aspects of the present disclosure. After filling, the volume of medical fluid within the pumping volume  107  can be measured. As illustrated, the plunger  110  is used to measure the height of the pumping volume  107  and/or the tubing  102  to determine the volume of medical fluid within the pumping volume  107 . 
     During the measurement phase, the downstream portion  108  of the tubing  102  remains blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . Further, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     Further, during measurement, the first plunger biasing member  164   a  applies a force to the plunger  110  to allow the plunger  110  to contact the tubing  102  to determine the height of the tubing  102  and/or the pumping volume  107 . In the depicted example, the force applied by the first plunger biasing member  164   a  can be sufficient to maintain contact with the tubing  102  without creating excess pressure within the pumping volume. 
       FIG. 7C  is an illustration of the peristaltic pump  100  of  FIG. 5A  in a delivery phase, in accordance with various aspects of the present disclosure.  FIG. 7D  is an illustration of the peristaltic pump  100  of  FIG. 5A  in a delivered position, in accordance with various aspects of the present disclosure. With reference to  FIGS. 7C and 7D , the peristaltic pump  100  delivers medical fluid through a downstream portion  108  to a downstream location, such as a patient. As illustrated, the plunger  110  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  to compress the pumping volume  107  to a compressed or reduced state. 
     During operation, the compression of the pumping volume  107  expels or otherwise administers fluid from the pumping volume  107  to a downstream location. The rate of administration of the medical fluid can be controlled by the force and velocity of the plunger  110 . 
     As described herein, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively force the plunger  110  to compress the pumping volume  107  to a compressed or reduced state. In some embodiments, the second plunger biasing member  164   b  can force the plunger  110  to compress the pumping volume  107  to a compressed or reduced state without the cooperation of the first plunger biasing member  164   a.    
     During administration, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     During the compression of the pumping volume  107 , medical fluid is forced from the pumping volume  107  to a downstream location through the downstream portion  108  of the tubing  102 . 
       FIG. 8A  is a simplified perspective view of a peristaltic pump  100 , in accordance with various aspects of the present disclosure.  FIG. 8B  is a top view of the peristaltic pump  100  of  FIG. 8A .  FIG. 8C  is a back view of the peristaltic pump  100  of  FIG. 8A . With reference to  FIGS. 8A-8C , the peristaltic pump  100  can independently control the operation of a first plunger  110   a  and a second plunger  110   b  to facilitate measurement of the volume within the tubing and to control the contact area and force applied to the tubing. Advantageously, the configuration of the peristaltic pump  100  can permit volume measurements without exerting excess force during a measurement phase. 
     In the depicted example, the peristaltic pump  100  includes a first plunger  110   a , a second plunger  110   b , an upstream occluder or valve  120 , and a downstream occluder or valve  130 , each configured to contact and manipulate the tubing to deliver fluid from a fluid source to the patient. In some embodiments, the first plunger  110   a , the second plunger  110   b , the upstream valve  120 , and the downstream valve  130  can move in coordinated, sequential steps to pump fluid through the tubing. 
     In some embodiments, the first plunger  110   a  can be configured to contact the tubing to measure the volume within the pumping volume. The second plunger  110   b  can be configured to contact the tubing to administer fluid during a delivery phase of operation. As illustrated, the first plunger  110   a  and the second plunger  110   b  can have different geometries to vary the contact area in contact with the tubing during operation. As illustrated, the first plunger  110   a  can have a smaller contact area with the tubing compared to the second plunger  110   b . In some embodiments, the first plunger  110   a  and the second plunger  110   b  can have similar or same sized contact areas. Further, as described herein, the first plunger  110   a  and the second plunger  110   b  can apply different or varying forces to the tubing. 
     As described herein, the first plunger  110   a , the second plunger  110   b , the upstream valve  120 , and/or the downstream valve  130  can be moved by one or more actuators. 
       FIG. 9  is an exploded view of components of the peristaltic pump  100  of  FIG. 8A . 
     As previously described, the peristaltic pump  100  can include a camshaft  150  to actuate the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . In the depicted example, the camshaft  150  includes one or more cam lobes, such as a first plunger cam lobe  154   a , a second plunger cam lobe  154   b , an upstream valve cam lobe  152 , and/or a downstream valve cam lobe  156 . 
     In the depicted example, the peristaltic pump  100  includes a split rocker arrangement with a first plunger valve rocker  111   a  directly coupled to the first plunger  110   a  and a second plunger valve rocker  111   b  directly coupled to the second plunger  110   b . In the depicted example, the first plunger valve rocker  111   a  is aligned, positioned, or otherwise configured to be actuated by the first plunger cam lobe  154   a . During operation, a portion of the first plunger valve rocker  111   a  can engage or slide along the cam profile of the first plunger cam lobe  154   a  to translate the geometry of the cam profile into movement of the first plunger valve rocker  111   a  and the first plunger  110   a . As can be appreciated, the first plunger valve rocker  111   a  and therefore the first plunger  110   a  may be independently moved or actuated separate from the actuation of the second plunger valve rocker  111   b  and the second plunger  110   b  during certain portions of operation (e.g., a measurement phase). 
     In the depicted example, a first plunger biasing member  164   a  can act upon the first plunger valve rocker  111   a  to urge the first plunger  110   a  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the first plunger valve rocker  111   a  by the rotation of the first plunger cam lobe  154   a  can overcome the biasing force to lift or otherwise actuate the first plunger  110   a  independent of the second plunger valve rocker  111   b  and the second plunger  110   b . Therefore, the force applied to the first plunger  110   a  can vary in response to the actuation of the first plunger valve rocker  111   a  by the rotation of the first plunger cam lobe  154   a.    
     During operation, the arrangement of the first plunger valve rocker  111   a , the first plunger cam lobe  154   a , and the first plunger biasing member  164   a  can allow the first plunger  110   a  to contact the tubing during a measurement phase with a reduced contact area and without administering the fluid within the pumping volume or damaging the tubing. 
     In the depicted example, the second plunger valve rocker  111   b  is aligned, positioned, or otherwise configured to be actuated by the second plunger cam lobe  154   b . During operation, a portion of the second plunger valve rocker  111   b  can engage or slide along the cam profile of the second plunger cam lobe  154   b  to translate the geometry of the cam profile into movement of the second plunger valve rocker  111   b  and the second plunger  110   b . As can be appreciated, the second plunger valve rocker  111   b  and therefore the second plunger  110   b  may be independently moved or actuated separate from the actuation of the first plunger valve rocker  111   a  and the first plunger  110   a  during certain portions of operation (e.g., a delivery phase). In some embodiments, during certain movements (e.g., during a delivery phase of operation) the second plunger valve rocker  111   b  can move in tandem with the first plunger valve rocker  111   a  to move both the first plunger  110   a  and the second plunger  110   b.    
     In the depicted example, a second plunger biasing member  164   b  can act upon the second plunger valve rocker  111   b  to urge the second plunger  110   b  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the second plunger valve rocker  111   b  by the rotation of the second plunger cam lobe  154   b  can overcome the biasing force to lift or otherwise actuate the second plunger  110   b  independent of the first plunger valve rocker  111   a  and the first plunger  110   a . Therefore, the force applied to the second plunger  110   b  can vary in response to the actuation of the second plunger valve rocker  111   b  by the rotation of the second plunger cam lobe  154   b.    
     During operation, the arrangement of the second plunger valve rocker  111   b  and the second plunger biasing member  164   b  relative to the first plunger valve rocker  111   a  and the first plunger biasing member  164   a  allows the peristaltic pump  100  to apply additional force to the tubing via the first plunger  110   a  and the second plunger  110   b  during certain portions of operation (e.g., the delivery phase) while allowing the a reduced force via the first plunger  110   a  during other portions of operation (e.g., the measurement phase). In some embodiments, the force applied by the second plunger biasing member  164   b  to the second plunger  110   b  is higher than the biasing force applied by the first plunger biasing member  164   a  to the first plunger  110   a . Optionally, the force applied by the second plunger biasing member  164   b  to the second plunger  110   b  is sufficient to allow fluid delivery. In some embodiments, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively provide sufficient force via the first plunger  110   a  and the second plunger  110   b  to allow for fluid delivery. 
     Further, the arrangement or phasing of the first plunger cam lobe  154   a  and the second plunger cam lobe  154   b  about the camshaft  150  can be modified to provide a desired sequence of actuation or movement of the first plunger  110   a  and the second plunger  110   b  as the camshaft  150  is rotated. For example, the cam lobes can each have a cam profile and/or a relative arrangement that includes a measurement phase that applies the first plunger  110   a  to the tubing with a reduced spring force and a delivery phase that applies the second plunger  110   b  with additional force. 
       FIG. 10A  is an illustration of the peristaltic pump  100  of  FIG. 8A  in a filling phase, in accordance with various aspects of the present disclosure. During operation, the tubing  102  draws in medical fluid  10  during the filling phase. As illustrated, the first plunger  110   a  and the second plunger  110   b  are withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the pumping volume  107  to an original or expanded state. 
     In the depicted example, the expansion of the pumping volume  107  draws in fluid into the pumping volume  107 . As illustrated, during the expansion of the pumping volume  107 , the downstream portion  108  of the tubing  102  is blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . 
     During the expansion of the pumping volume  107 , medical fluid  10  is drawn into pumping volume  107  from the upstream portion  106  of the tubing  102 . As illustrated, during the expansion of the pumping volume  107 , the upstream portion  106  of the tubing  102  is unobstructed by the upstream valve  120 , permitting medical fluid  10  into the pumping volume  107 . During operation, the upstream valve  120  is withdrawn or retracted from a compressed portion of the tubing  102 , allowing the tubing walls  104  to resiliently expand the upstream portion  106  to an original or expanded state. 
     In the depicted example, the expansion of the upstream portion  106  permits the flow of medical fluid  10  into the pumping volume  107 . Advantageously, and as described herein, the arrangement of the first plunger cam lobe  154   a  and the second plunger cam lobe  154   b  can prevent the first plunger biasing member  164   a  and the second plunger biasing member from applying force to the first plunger  110   a , the second plunger  110   b , and/or the tubing  102  during the filling phase. 
       FIG. 10B  is an illustration of the peristaltic pump  100  of  FIG. 8A  in a measurement position, in accordance with various aspects of the present disclosure. After filling, the volume of medical fluid within the pumping volume  107  can be measured. As illustrated, the first plunger  110   a  is used to measure the height of the pumping volume  107  and/or the tubing  102  to determine the volume of medical fluid within the pumping volume  107 . 
     During the measurement phase, the downstream portion  108  of the tubing  102  remains blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . Further, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     Further, during measurement, the first plunger biasing member  164   a  applies a force to the first plunger  110   a  to allow the first plunger  110   a  to contact the tubing  102  to determine the height of the tubing  102  and/or the pumping volume  107 . In the depicted example, the force applied by the first plunger biasing member  164   a  via the first plunger  110   a  can be sufficient to maintain contact with the tubing  102  without creating excess pressure within the pumping volume. 
       FIG. 10C  is an illustration of the peristaltic pump  100  of  FIG. 8A  in a delivery phase, in accordance with various aspects of the present disclosure.  FIG. 10D  is an illustration of the peristaltic pump  100  of  FIG. 8A  in a delivered position, in accordance with various aspects of the present disclosure. With reference to  FIGS. 10C and 10D , the peristaltic pump  100  delivers medical fluid through a downstream portion  108  to a downstream location, such as a patient. As illustrated, the first plunger  110   a  and the second plunger  110   b  are actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  to compress the pumping volume  107  to a compressed or reduced state. 
     During operation, the compression of the pumping volume  107  expels or otherwise administers fluid from the pumping volume  107  to a downstream location. The rate of administration of the medical fluid can be controlled by the force and velocity of the first plunger  110   a  and the second plunger  110   b.    
     As described herein, the first plunger biasing member  164   a  and the second plunger biasing member  164   b  cooperatively force the first plunger  110   a  and the second plunger  110   b , respectively, to compress the pumping volume  107  to a compressed or reduced state. In some embodiments, the second plunger biasing member  164   b  can force the second plunger  110   b  to compress the pumping volume  107  to a compressed or reduced state without the cooperation of the first plunger biasing member  164   a  or the first plunger  110   a.    
     During administration, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     During the compression of the pumping volume  107 , medical fluid is forced from the pumping volume  107  to a downstream location through the downstream portion  108  of the tubing  102 . 
       FIG. 11A  is a perspective view of a peristaltic pump  100 , in accordance with various aspects of the present disclosure.  FIG. 11B  is a simplified view of the peristaltic pump  100  of  FIG. 11A . In the depicted example, the peristaltic pump  100  includes a feeler pin  190  to measure the volume of the fluid being delivered to the patient. In the depicted example, the peristaltic pump  100  includes a plunger  110 , an upstream occluder or valve  120 , and a downstream occluder or valve  130 , each configured to contact and manipulate the tubing to deliver fluid from a fluid source to the patient. Advantageously, the configuration of the peristaltic pump  100  can permit volume measurements without a dedicated measurement phase. 
     In the depicted example, the peristaltic pump  100  can include a camshaft  150  to actuate the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . In the depicted example, the camshaft  150  includes one or more cam lobes, such as a plunger cam lobe  154 , an upstream valve cam lobe  152 , and/or a downstream valve cam lobe  156 . 
     As described herein, the geometry of the respective cam lobes can be shaped or modified to allow for a desired actuation or movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . In some embodiments, the cam lobes of the camshaft  150  actuate one or more rockers to control the plunger  110 , the upstream valve  120 , and/or the downstream valve  130 . 
     In the depicted example, biasing members, such as springs can urge the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  toward the tubing and/or the backer  180 . 
     Further, the arrangement or phasing of the cam lobes about the camshaft  150  can be modified to provide a desired sequence of actuation or movement of the plunger  110 , the upstream valve  120 , and/or the downstream valve  130  as the camshaft  150  is rotated. For example, the plunger cam lobe  154 , the upstream valve cam lobe  152 , and/or the downstream valve cam lobe  156  can each have a cam profile and/or a relative arrangement that eliminates or otherwise does not include a dedicated measurement phase where the plunger  110  is actuated against a pumping volume of the tubing closed by the upstream valve  120  and the downstream valve  130 . 
     In the depicted example, the peristaltic pump  100  includes a single rocker arrangement with a plunger valve rocker  111  directly coupled to the plunger  110 . In the depicted example, the plunger valve rocker  111  is aligned, positioned, or otherwise configured to be actuated by the plunger cam lobe  154 . During operation, a portion of the plunger valve rocker  111  can engage or slide along the cam profile of the plunger cam lobe  154  to translate the geometry of the cam profile into movement of the plunger valve rocker  111  and the plunger  110 . In the depicted example, a plunger biasing member  164  can act upon the plunger valve rocker  111  to urge the plunger  110  toward the tubing and/or the backer  180 . As can be appreciated, actuation of the plunger valve rocker  111  by the rotation of the plunger cam lobe  154  can overcome the biasing force to lift or otherwise actuate the plunger  110 . Therefore, the force applied to the plunger  110  can vary in response to the actuation of the plunger valve rocker  111  by the rotation of the plunger cam lobe  154 . 
     In some embodiments, an upstream valve rocker  121  is coupled to the upstream valve  120  and can move the upstream valve  120  in response to actuation from the upstream valve cam lobe  152 . As illustrated, an upstream valve biasing member  162  can act upon the upstream valve rocker  121  to urge the upstream valve  120  toward the tubing and/or the backer  180 . 
     Similarly, a downstream valve rocker  131  is coupled to the downstream valve  130  and can move the downstream valve  130  in response to actuation from the downstream valve cam lobe  156 . Similarly, a downstream valve biasing member  166  can act upon the downstream valve rocker  131  to urge the downstream valve  130  toward the tubing and/or the backer  180 . 
       FIG. 12  is a perspective view of the feeler pin  190  of the peristaltic pump  100  of  FIG. 11A . With reference to  FIGS. 11A, 11B, and 12 , the feeler pin  190  can determine the volume of fluid administered by the peristaltic pump  100 . During operation, the feeler pin  190  can be used to determine the height of the pumping volume within the tubing  102 , which can be used to determine the volume of the fluid administered by the peristaltic pump  100 . 
     In the depicted example, the feeler pin  190  can extend through the plunger  110  to contact the tubing  102  disposed between the plunger  110  and the backer  180 . As illustrated, the feeler pin  190  can extend through a slot  115  formed through the plunger  110 . In some embodiments, the feeler pin  190  has a rounded tip to contact the tubing  102 . 
     During operation, the feeler pin  190  can move with the tubing  102  as the height of the pumping volume changes. In some embodiments, the feeler pin  190  can include a biasing member  196  configured to urge the feeler pin  190  toward the tubing  102 , allowing the feeler pin  190  to maintain contact with the tubing during operation. As can be appreciated, the biasing force of the biasing member  196  can be sufficient to maintain contact with the tubing  102  without exerting excess force on the tubing. Optionally, the biasing member  196  can exert the biasing force against the feeler pin  190  via a feeler plate  197 . An opposite end of the biasing member  196  can engage against a feeler pin bracket  191 . 
     In some embodiments, the feeler pin  190  is coupled to the peristaltic pump  100  via the feeler pin bracket  191 . The feeler pin bracket  191  can include a passage to support the feeler pin  190  during operation. Optionally, the feeler pin bracket  191  can constrain the movement of the feeler pin  190  in a single measurement direction. For example, the feeler pin bracket  191  can constrain the movement of the feeler pin  190  in an axis perpendicular to the longitudinal axis of the tubing  102 . 
     In the depicted example, the peristaltic pump  100  can measure the position or height of the feeler pin  190  to determine the height of the pumping volume in the tubing  102 . As illustrated, the peristaltic pump  100  can include a position transducer  194  to detect the position of the feeler pin  190 . The feeler pin  190  can include a trigger portion  192  that provide a signal or identifiable portion of the position transducer  194 . Optionally, the trigger portion  192  can be magnetic and provide a signal to the position transducer  194 . The position transducer  194  can be mounted parallel to the direction of travel of the feeler pin  190  via a mounting bracket  195 . The height or position of the feeler pin  190  can be utilized to determine the volume of the pumping volume within the tubing  102 . 
       FIG. 13A  is an illustration of the peristaltic pump  100  of  FIG. 11A  in a filling phase, in accordance with various aspects of the present disclosure. During operation, the tubing  102  draws in medical fluid  10  during the filling phase. In the depicted example, the expansion of the pumping volume  107  draws in fluid into the pumping volume  107 . 
     As illustrated, during the expansion of the pumping volume  107 , the downstream portion  108  of the tubing  102  is blocked, pinched, or otherwise occluded by the downstream valve  130  to prevent or restrict backflow or contamination of fluid into the pumping volume  107 . 
     In the depicted example, the downstream valve  130  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  at the downstream portion  108  to occlude flow through the downstream portion  108  of the tubing  102 . During the expansion of the pumping volume  107 , medical fluid  10  is drawn into pumping volume  107  from the upstream portion  106  of the tubing  102 . 
     In the depicted example, the expansion of the upstream portion  106  permits the flow of medical fluid  10  into the pumping volume  107 . Advantageously, and as described herein, the feeler pin  190  can extend through the plunger  110  to maintain contact with the tubing  102  during the filling phase to permit measurement of the pumping volume. In the depicted example, the force applied by the biasing member  196  can be sufficient to maintain contact with the tubing  102  while allowing for the pumping volume  107  to be filled. 
       FIG. 13B  is an illustration of the peristaltic pump  100  of  FIG. 11A  in a delivery phase, in accordance with various aspects of the present disclosure.  FIG. 13C  is an illustration of the peristaltic pump  100  of  FIG. 11A  in a delivered position, in accordance with various aspects of the present disclosure. With reference to  FIGS. 13B and 13C , the peristaltic pump  100  delivers medical fluid through a downstream portion  108  to a downstream location, such as a patient. As illustrated, the plunger  110  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  to compress the pumping volume  107  to a compressed or reduced state. 
     During operation, the compression of the pumping volume  107  expels or otherwise administers fluid from the pumping volume  107  to a downstream location. As described herein, the plunger biasing member  164  force the plunger  110  to compress the pumping volume  107  to a compressed or reduced state. 
     During administration, the upstream portion  106  of the tubing  102  is blocked, pinched, or otherwise occluded by the upstream valve  120  to prevent or restrict inadvertent fluid flow into the pumping volume  107  and to prevent or restrict backflow of fluid into the medical container from the pumping volume  107 . 
     In the depicted example, the upstream valve  120  is actuated, moved downward, or otherwise engaged to compress the tubing walls  104  of the tubing  102  at the upstream portion  106  to occlude flow through the upstream portion  106  of the tubing  102 . During the compression of the pumping volume  107 , medical fluid is forced from the pumping volume  107  to a downstream location through the downstream portion  108  of the tubing  102 . 
     In the depicted example, the expansion of the downstream portion  108  permits the flow of medical fluid  10  out of the pumping volume  107 . The amount of medical fluid  10  administered from the pumping volume  107  during the delivery phase can be determined by the timing and sequence of the plunger  110 , the downstream valve  130  and the mechanical properties of the tubing  102 . 
     Advantageously, and as described herein, the feeler pin  190  can maintain contact with the tubing  102  during the delivery phase to permit measurement of the pumping volume during the entire cycle, providing more information to a clinician without interrupting fluid delivery. 
     The present disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. The disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. 
     A reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention. 
     The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. In one aspect, various alternative configurations and operations described herein may be considered to be at least equivalent. 
     A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples. A phrase such an embodiment may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples. A phrase such a configuration may refer to one or more configurations and vice versa. 
     In one aspect, unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. In one aspect, they are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain. 
     In one aspect, the term “coupled” or the like may refer to being directly coupled. In another aspect, the term “coupled” or the like may refer to being indirectly coupled. 
     Terms such as “top,” “bottom,” “front,” “rear” and the like if used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference. 
     Various items may be arranged differently (e.g., arranged in a different order, or partitioned in a different way) all without departing from the scope of the subject technology. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. 
     The Title, Background, Summary, Brief Description of the Drawings and Abstract of the disclosure are hereby incorporated into the disclosure and are provided as illustrative examples of the disclosure, not as restrictive descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the Detailed Description, it can be seen that the description provides illustrative examples and the various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter. 
     The claims are not intended to be limited to the aspects described herein, but is to be accorded the full scope consistent with the language claims and to encompass all legal equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of 35 U.S.C. § 101, 102, or 103, nor should they be interpreted in such a way.