A system for controlling the flow of fluid to a patient through a fluid path comprising: a fluid port (100) comprising: a fluid channel (120)； a fluid inlet (105) at a first end of the fluid channel configured to engage an outlet of a manually administered fluid source； a fluid outlet (110) at a second end of the fluid channel configured to deliver fluid from the manually administered fluid source to a fluid path (202, 204, 206) that provides fluid to a patient； at least one sensor (145, 148) configured to determine at least one fluid attribute from the manually administered fluid source； a flow controller (125, 130) that communicates with the at least one sensor that generates at least one flow modification signal in response to at least one determined attribute that matches at least one condition specified by at least one rule； and a flow control valve (115) that communicates with the flow controller and that is located within the fluid path (120) at a location separate and distinct from that of the fluid port (100), changing the valve of flow control (115) a level of fluid flow restriction from the manually administered fluid source and passing through it in response to receiving the at least one flow modification signal, at which to change a level of fluid flow restriction from the manually administered fluid source passing through the flow control valve comprises adjusting the current flow rate of the fluid passing through the flow control valve at a higher flow rate or less, in which the flow control valve partially restricts the fluid that passes through the flow control valve at the higher or lower rate； and wherein the at least one sensor is configured to automatically measure a volume of retracted descending fluid, in which the volume of retracted descending fluid is a total volume of the descending fluid from the fluid inlet and still within the fluid channel after that the flow of fluid through the fluid path is stopped.Un sistema para controlar el flujo
