System, method, and apparatus for infusing fluid

A peristaltic pump, comprising:

• a cam shaft;
• first and second pinch-valve cams coupled to the cam shaft;
• first and second pinch-valve cam followers configured to engage the first and second pinch-valve cams;
• a plunger cam coupled to the cam shaft;
• a plunger-cam follower configured to engage the plunger cam;
• a tube receiver configured to receive a tube;
• a spring-biased plunger coupled to the plunger-cam follower, wherein:
• the plunger cam engages with the plunger-cam follower such that as the plunger-cam follower is actuated away from a center axis of the cam shaft via the plunger cam, the spring biased plunger actuates away from the tube receiver and the tube,
• the plunger cam follower is configured to disengage from the plunger cam, and
• a spring coupled to the spring-biased plunger biases the spring-biased plunger to apply a crushing force to the tube;
• a position sensor operatively coupled to the spring-biased plunger configured to determine a position of the spring-biased plunger when the plunger-cam follower is disengaged from the plunger cam and the spring applies the crushing force from the spring-biased plunger against the tube;
• and
• a processor coupled to the position sensor, wherein the processor is configured to estimate fluid flow utilizing the position of the spring-biased plunger as indicated by the position sensor when the plunger-cam follower is disengaged from the plunger cam and the spring applies the crushing force from the spring-biased plunger against the tube.