Module 13 - Infusion

Question 1

Why is infusion therapy used for medication?

Answer 1

The goal of infusion therapy is to bring fluids directly into the circulation for well distributed and sustaining effect

Question 2

Explain the block diagram for gravity infusion pump systems:

Answer 2

First you have a fluid container
then driving force
then transport system
then a flow controller
then vascular access
and then it enters person circulation

Question 3

What are the two important mechanisms for infusion?

Answer 3

Gravity driven

Syringe / volumetric pump, positive displacement

Question 4

Explain the physics behind the gravity driven infusion mechanism:

Answer 4

Top part is a fluid container. Gravity is the driving force behind administering the fluid. Then a transmitting system, lots of tubing.

You have fluid container
driving force
transmitting system
vascular access system
flowcontroller

Question 5

Explain the physics behind a syringe pump

Answer 5

used for low volume, low flow rate:

Workings:
— plunger connected to the syringe pump and held in place by the syringe pump clamper. As the motor turns, the carriage moves, the plunger gets depressed, and the fluid gets infused

Question 6

Explain the physics behind a volumetric pump

Answer 6

Fluid container, tubing system and a driving force which is a pump.
A piston is drawn downwards, then fluid goes from bag into the cylinder. Then a valve is switched and the piston is pushed upwards. Then fluid flows from the cylinder into the patient.

peristaltic mechanisms with motors and gearbox.

Question 7

What influences time for medication to reach the patients?

Answer 7

• viscocity
• temperature
• compliance
• resistance

compliance of tubes and syringes, and resistance to flow

Question 8

What determines changes in flow?

Answer 8

RC-time
resistance of mixing
compliance of tubes