Patient controlled analgesia device

• US 8,920,382 B1
• Filed: 02/28/2013
• Issued: 12/30/2014
• Est. Priority Date: 03/07/2012
• Status: Active Grant

• Current Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico)
• Original Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico)
• Inventors: Hauswald, Mark
• Primary Examiner(s): Bosworth, Kami A
• Assistant Examiner(s): Janson, Glen
• Application Number:
  US13/815,405
• Time in Patent Office: 670 Days
• Field of Search: 604/125, 604/131, 604/181, 604/183, 604/186, 604/187, 604/220, 604/227, 604/229
• US Class Current: 604/183
• CPC Class Codes: A61M 2005/1405 Patient controlled analgesia [PCA]
• CPC Class Codes: A61M 2005/3115 spring-assisted
• CPC Class Codes: A61M 2202/048 Anaesthetics see also A61M19/00
• CPC Class Codes: A61M 5/141 with capillaries for restricting fluid flow
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/1424 Manually operated pumps
• CPC Class Codes: A61M 5/3148 Means for causing or aiding aspiration or plunger retraction
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button

Abstract

A mechanical patient-controlled analgesia device for injecting medicine into a patient'"'"'s IV, includes an IV reservoir and a syringe communicated to the IV reservoir and having a syringe plunger. A mechanical biasing element is provided for exerting bias on the syringe plunger in a first syringe-filling direction to draw medicine from the IV reservoir into the syringe. An injection plunger is operable by the patient to move the syringe plunger in a second injection direction against the bias to inject the medicine in the syringe into a patient'"'"'s IV. The injection plunger is movable independently of the syringe plunger and is engaged with but unconnected to the syringe plunger when the patient moves the injection plunger to inject the medicine. The patient can inject only a calibrated amount of medicine drawn into the syringe as determined by calibration of the biasing element and a metering element for a given viscosity of the medication.

Claims

1. A patient-controlled analgesia device, comprising an IV medication reservoir, a syringe communicated to the IV medication reservoir and having a syringe plunger, a biasing element for exerting bias on the syringe plunger in a first syringe-filling direction to draw medication from the IV medication reservoir into the syringe, and an injection plunger operable by the patient to move the syringe plunger in a second injection direction against the bias to inject the medication in the syringe into a patient'"'"'s IV, said injection plunger being movable independently of the syringe plunger and being engaged with but unconnected to the syringe plunger when the patient moves the injection plunger to inject the medication.

2. The device of claim 1 further including a one-way valve to prevent medication from being transferred from the syringe back into the IV medication reservoir when the syringe plunger is moved in the second injection direction.

3. The device of claim 1 further including a second one-way valve to prevent flow of medication from the patient'"'"'s IV back to the syringe.

4. The device of claim 1 wherein the injection plunger includes a patient-operable end and an opposite end that engages but is unconnected to an outer end of the syringe plunger when the patient moves the injection plunger to inject the medication.

5. The device of claim 1 wherein the syringe plunger includes an outer end spaced from a fixed support member, the biasing element being disposed between the outer end of the syringe plunger and the fixed support member.

6. The device of claim 1 wherein the biasing element is a compression spring.

7. The device of claim 1 further including a container in which the IV medication reservoir, the syringe, and the biasing element are enclosed.

8. The device of claim 7 wherein the injection plunger includes an outer patient-operable end disposed outside the container and an inner end inside the container that engages but is unconnected to the syringe plunger.

9. The device of claim 7 wherein the container includes an opening to admit air into the container.

10. A patient-controlled analgesia device, comprising an IV medication reservoir, a syringe communicated to the IV medication reservoir by a metering element and having a syringe plunger, a mechanical biasing element for exerting bias on the syringe plunger to move it in a first syringe-filing direction to draw medication from the IV medication reservoir into the syringe wherein the metering element and the biasing spring are calibrated to permit a calibrated amount of medication to be drawn for a given time into the syringe from the IV medication reservoir, and an injection plunger operable by the patient to move the syringe plunger in a second opposite injection direction against the bias to inject the medication in the syringe into a patient'"'"'s IV, said injection plunger being movable independently of the syringe plunger and being engaged with but unconnected to the syringe plunger when the patient moves the injection plunger to inject the medication.

11. The device of claim 10 further including a one-way valve to prevent medication from being transferred from the syringe back into the IV medication reservoir when the syringe plunger is moved in the second opposite injection direction.

12. The device of claim 10 further including a second one-way valve to prevent flow of medication from the patient'"'"'s IV back to the syringe.

13. The device of claim 10 wherein the injection plunger includes a patient-operable end and an opposite end that engages but is unconnected to an outer end of the syringe plunger when the patient moves the injection plunger to inject the medication.

14. The device of claim 10 wherein the syringe plunger includes an outer end spaced from a fixed support member, the mechanical biasing element being disposed between the outer end of the syringe plunger and the fixed support member.

15. The device of claim 10 wherein the biasing element is a compression spring.

16. The device of claim 10 further including a container in which the IV medication reservoir, the syringe, and the mechanical biasing element are enclosed.

17. The device of claim 16 wherein the injection plunger includes an outer patient-operable end disposed outside the container and an inner end that engages but is unconnected to the syringe plunger.

18. The device of claim 16 wherein the container includes an opening to admit air into the container.

19. A patient-controlled analgesia device, comprising an IV medication reservoir, a syringe communicated to the IV medication reservoir by a metering element and having a syringe plunger which is biased by a spring biasing element in an upward syringe-filling direction to draw medication from the IV medication reservoir into the syringe wherein the metering element and the spring biasing element are calibrated to permit a calibrated amount of medication to be drawn for a given time into the syringe from the IV medication reservoir, an injection plunger disposed above the syringe plunger and operable by the patient to move the syringe plunger in a downward injection direction against the bias to inject the medication in the syringe into a patient'"'"'s IV, said injection plunger being movable independently of the syringe plunger and being engaged with but unconnected to the syringe plunger, and a one-way valve to prevent medication from being transferred from the syringe back into the IV medication reservoir when the syringe plunger is moved in the downward injection direction.

20. The device of claim 19 further including a second one-way valve to prevent flow of medication from the patient'"'"'s IV back to the syringe.

21. The device of claim 19 further including a container in which the IV medication reservoir, the syringe, and the spring biasing element are enclosed.

22. The device of claim 21 wherein the injection plunger includes an outer patient-operable end disposed outside the container and an inner end inside the container that engages but is unconnected to the syringe plunger.

23. The device of claim 21 wherein the container includes an opening to admit air into the container.