Systems and methods for controlling an infusion pump
Systems and methods for determining the position of a fluid within a fluid source and infusion line coupled to an infusion flow control device are described herein. An exemplary system and method includes sampling fluid pressure upstream of an infusion pump, and calculating fluid pressure slope profiles. By sampling fluid pressure upstream of an infusion pump at discrete intervals and monitoring fluid pressure slope profiles, conditions of fluid flow, including unintentional fluid flow through an infusion line or a defective check valve in an infusion line, are detected, and fluid flow through an infusion pump is controlled.
1 . A method of detecting equilibrium during fluid flow through an infusion pump from a first fluid source and a second fluid source, the method comprising:
sampling fluid pressure of the first fluid source and the second fluid source within an infusion line upstream of the infusion pump operating at a first fluid flow rate;
calculating a fluid pressure slope profile, the fluid pressure slope profile being a change in pressure over discrete intervals;
detecting equilibrium between a head height of the first and second fluid sources, wherein the fluid pressure slope profile comprises first, second and third slope profile segments, and equilibrium between the first and second fluid source head heights is detected when a slope of the third slope profile segment is less than one-half of a slope of each of the first slope profile segment and the second slope profile segment; and
setting the infusion pump to a post-equilibrium fluid flow rate based on the detected equilibrium.
2 . The method of claim 1 , the detecting equilibrium comprising:
detecting a change in pressure indicating the head height of the second fluid source is equal to the head height of the first fluid source.
3 . The method of claim 1 , further comprising:
maintaining the first fluid flow rate until the second fluid source is flushed to the infusion pump.
4 . The method of claim 3 , wherein maintaining the first fluid flow rate until the second fluid source is flushed to the infusion pump comprises an additional volume predetermined based on known parameters of an infusion set comprising the infusion line.
5 . The method of claim 3 , wherein maintaining the first fluid flow rate until the second fluid source is flushed to the infusion pump comprises an additional volume selected by a user.
6 . The method of claim 1 , further comprising:
altering the first fluid flow rate to a post-flush rate after detecting the equilibrium between the head height of the first and a second fluid source.
7 . The method of claim 6 , further comprising setting the post-flush rate higher than the first fluid flow rate.
8 . The method of claim 6 , further comprising setting the post-flush rate higher than the first fluid flow rate plus a second fluid flow rate.
9 . The method of claim 6 , further comprising setting the post-flush rate equal to a pre-flush rate.
10 . The method of claim 6 , further comprising generating a prompt to request an indication of one of a length of time and a volume of fluid to be used at the post-flush rate.
11 . The method of claim 6 , further comprising generating a prompt to request an indication of one of a length of time and a volume of fluid to be used at a pre-flush rate prior to altering the first fluid flow rate to the post-flush rate.
12 . The method of claim 1 , wherein the head height of the first fluid source is a level of fluid in a primary fluid source container.
13 . The method of claim 1 , wherein the head height of the second fluid source is a level of fluid in a secondary infusion line.
14 . The method of claim 1 , wherein the slope of the third slope profile segment is near zero.
15 . A system for detecting equilibrium between first and second fluid sources:
an infusion pump coupled with an infusion line;
a pressure sensor coupled to the infusion line upstream of the infusion pump, the pressure sensor configured to sample fluid pressure within the infusion line;
a memory adapted to store the fluid pressure values; and
a processor in communication with the pressure sensor and the memory, the processor configured to:
sample fluid pressure of the first fluid source and the second fluid source within an infusion line upstream of the infusion pump operating at a first fluid flow rate;
calculate a fluid pressure slope profile, the fluid pressure slope profile being a change in pressure over discrete intervals;
detect equilibrium between a head height of the first and second fluid sources, wherein the fluid pressure slope profile comprises first, second and third slope profile segments, and equilibrium between the first and second fluid source head heights is detected when a slope of the third slope profile segment is less than one-half of a slope of each of the first slope profile segment and the second slope profile segment; and
set the infusion pump to a post-equilibrium fluid flow rate based on the detected equilibrium.
16 . The system of claim 15 , wherein the processor is configured to alter the first fluid flow rate to a post-flush rate after detecting the equilibrium between the head height of the first and a second fluid sources.
17 . The system of claim 16 , wherein the processor is configured to one of:
set the post-flush rate higher than the first fluid flow rate;
set the post-flush rate higher than the first fluid flow rate plus a second fluid flow rate; and
set the post-flush rate equal to a pre-flush rate.
18 . The system of claim 15 , wherein the processor is configured to detect the equilibrium between the head height of the first and second fluid sources by detecting a change in pressure indicating the head height of the second fluid source is equal to the head height of the first fluid source.
19 . The system of claim 15 , wherein the processor is configured to control the system to maintain the first fluid flow rate until the second fluid source is flushed to the infusion pump.
20 . The system of claim 18 , wherein the processor is configured to maintain the first fluid flow rate until the second fluid source is flushed to the infusion pump based on one of:
an additional volume predetermined based on known parameters of the infusion line; and
an additional volume selected by a user.