Syringe pump, and related method and system
A method for discharging fluid from a syringe and for mitigating occlusion conditions includes actuating the plunger of a syringe into a barrel. The method monitors fluid pressure within the barrel of the syringe and determines that an occlusion exists when the fluid pressure exceeds a predetermined threshold. The method actuates the plunger out of the barrel by a predetermined amount in response to the detected occlusion and actuates the plunger of the syringe into the barrel until a measured fluid pressure within the barrel of the syringe exceeds another predetermined threshold.
1. A syringe pump comprising:
a body;
a motor;
a lead screw operatively coupled to the motor, wherein the motor is configured to actuate the lead screw;
a linear cam moveable between an extended position and a retracted position;
first and second half-nut arms pivotally coupled together, each having first and second ends, wherein the second ends of the first and second half-nut arms are configured to engage with the linear cam such that actuation of the linear cam toward the extended position causes the first ends of the first and second half-nut arms to pivotally approach each other to cause the first ends to engage the lead screw.
2. The syringe pump according to claim 1 , further comprising a spacer coupled to one of the first and second half-nut arms.
3. The syringe pump according to claim 1 , further comprising a pivot pin configured to provide the pivotal coupling between the first and second half-nut arms.
4. The syringe pump according to claim 1 , wherein the linear cam includes two ramping surfaces configured to engaged with the second ends of the first and second half-nut arms.
5. The syringe pump according to claim 1 , further comprising a bias member configured to bias the second ends of the first and second half-nut arms away from each other.
6. The syringe pump according to claim 5 , wherein the bias member is a spring.
7. The syringe pump according to claim 1 , further comprising a plunger head assembly.
8. The syringe pump according to claim 7 , wherein the plunger head assembly includes a user actuator operatively coupled to the linear cam to actuate the linear cam toward and away from a half-nut assembly.
9. The syringe pump according to claim 1 , further comprising a plunger head assembly, the plunger head assembly comprising:
a dial having a first position and a second position, wherein the dial is configured to actuate between the first position and the second position;
a plunger tube configured to slideably engage with the body; and
a plunger head operatively coupled to the plunger tube.
10. The syringe pump according to claim 9 , further comprising a shaft operatively coupled to the dial, wherein the shaft and the dial are configured such that actuation of the dial actuates the shaft.
11. The syringe pump according to claim 10 , further comprising a cam coupled to the shaft.
12. The syringe pump according to claim 11 , further comprising a rocker arm pivotally coupled to the plunger head assembly, the rocker arm having a cam follower configured to engage the cam.
13. The syringe pump according to claim 12 , further comprising a pivotable jaw member operatively coupled to the rocker arm.
14. The syringe pump according to claim 12 , further comprising:
a first gear coupled to the rocker arm and a pivotable jaw member; and
a second gear coupled to another pivotable jaw member, wherein the first and second gears are configured to engage each other, wherein the pivotable jaw members are configured to grasp onto a syringe plunger flange.
15. The syringe pump according to claim 14 , wherein the cam and the rocker arm are configured such that additional actuation of the dial toward the second position when the pivotable jaw members grasp onto the syringe plunger flange causes the cam follower to disengage from the cam.
16. The syringe pump according to claim 14 , further comprising a bias member configured to urge the cam follower of the rocker arm toward the cam.
17. The syringe pump according to claim 14 , wherein the cam includes a detent configured to interface with the rocker arm such that the cam is held in the first position until a predetermined amount of torque is applied to the dial to urge the dial toward the second position.
18. The syringe pump according to claim 1 , wherein a plunger head includes a shaft having a rod actuator coupled thereto.
19. The syringe pump according to claim 1 , wherein a plunger tube includes a rod, wherein the rod is coupled via a link within a plunger head.
20. The syringe pump according to claim 1 , wherein a rod is operatively coupled to the linear cam.
21. The syringe pump according to claim 1 , wherein the first ends of the first and second half-nut arms each includes threads configured to engage the lead screw when the second ends of the first and second half-nut arms are proximal to one another.
22. The syringe pump of claim 1 , wherein a plunger head assembly comprises a pressure sensor for monitoring a pressure of an agent being dispensed from a syringe.
23. The syringe pump of claim 22 , wherein a plunger flange of the syringe is held against the pressure sensor.
24. The syringe pump of claim 1 , wherein the syringe pump further comprises a barrel flange clip, said barrel flange clip configured to retain a barrel flange of the syringe.
25. The syringe pump of claim 24 , wherein the barrel flange clip comprises an optical sensor and a light source configured to detect a presence of the barrel flange, said light source obscured in the presence of said barrel flange.
26. A syringe pump comprising:
a body;
a motor;
a lead screw operatively coupled to the motor, wherein the motor s configured to actuate the lead screw;
a linear cam moveable between an extended position and a retracted position;
first and second haft-nut arms pivotally coupled together, each having first and second ends, wherein the second ends of the first and second half-nut arms are configured to engage with the linear cam such that actuation of the linear cam toward the extended position causes the first ends of the first and second haft-nut arms to pivotally approach each other to cause the first ends to engage the lead screw; and
at least one processor operatively coupled to the motor and configured to control the rotation of the motor to thereby control actuation of a plunger head assembly, the at least one processor is also operatively coupled to a force sensor to receive a measured force therefrom, wherein the at least one processor is configured to:
receive a target flow rate of the syringe loaded on a syringe pump;
determine a therapy actuation speed corresponding to the target flow rate;
command the motor to actuate a plunger of the syringe out of a barrel at a first predetermined speed unto a force sensor coupled to the plunger measures a force that is less than a first predetermined force threshold or the plunger travels out of the barrel by a first predetermined distance;
command the motor to actuate the plunger of the syringe into the barrel at a second predetermined speed greater than the therapy actuation speed until the force sensor coupled to the plunger measures a force that exceeds a second predetermined threshold or the plunger travels into the barrel by a second predetermined distance; and
command the motor to actuate the plunger of the syringe into the barrel at the therapy actuation speed.
27. A method for using a syringe pump, the method comprising:
providing a syringe pump of claim 1 ;
receiving a target flow rate of a syringe loaded on the syringe pump;
determining a therapy actuation speed corresponding to the target flow rate;
commanding the motor to actuate a plunger of the syringe out of a barrel at a first predetermined speed until a force sensor coupled to the plunger measures a force that is less than a first predetermined force threshold or the plunger travels out of the barrel by a first predetermined distance;
commanding the motor to actuate the plunger of the syringe into the barrel at a second predetermined speed greater than the therapy actuation speed until the force sensor coupled to the plunger measures a force that exceeds a second predetermined threshold or the plunger travels into the barrel by a second predetermined distance; and
commanding the motor to actuate the plunger of the syringe into the barrel at the therapy actuation speed.