CONTENTS
1.Infusion Pumps
2.
components of drugs infusion systems
3.Implantable infusion pump
4.Drop rate counter type infusion pump.
5.programmable volumetric infusion pump
•In medical application intravenous
fluid and drugs need to be infused over a period of time which could be several
minute , hours and days.
•Some of the common method is to
inject liquid by means of syringe manually setting drip rate of gravity feed
intravenous infusion set.
•The first improvement was the
electronic counter that could quickly determine the drip rate of IV delivery.
•Gradually many smart and small pump
have been developed.
•Use of microprocessor has made it
easy to control the rate of delivery.
fig- most widely used syringe pump.(fresenius kabi-Injectomat agilia)
COMPONENTS OF DRUG INFUSION SYSTEM
Drug infusion system
consists of two components
1.A mechanism that
delivers the drug
2.Means of controlling
the rate of delivery
System
can be open loop system or close loop system.
In open loop system the rate is set by the
clinician but in close loop system the body parameter is monitored and the rate
varies according to body condition and set automatically by microprocessor.
IMPLANTABLE INFUSION SYSTEMS
•This system is designed to provide drug to the human
body whenever required without
puncturing the skin.
•This is useful for the patient requiring continuous drug
supply or at regular interval.
•Here the pumps apply a known pressure to a reservoir of
the drug and there is a high resistance connection between the pump and the
site where the drug is to be delivered.
•A commercial implantable infusion pump which is
available for human use is the INFUSAID.
•This pump can be easily refilled but its rate of
infusion can not be regulated. It is completely mechanical.
•The chamber can be refilled by means of a needle that
can enter the reservoir and can refill without any leakage to the surrounding.
•The rate of infusion is determined by-
•Temperature
•Fluid viscosity
Flow
restrictor
•Drug delivery is said to be open if the rate of infusion
is set previously and is not automatically altered by patient response.
•Volumetric pump may be controlled by the step size or
frequency of stepper motor.
•In close loop external control unit can be used to
control the infusion pump by giving instruction wirelessly from outside.
•In some cases the machine has two way communication
system in which any problem in machine is directly informed to physician .
DRUG RATE COUNTER TYPE INFUSION PUMP
•The heart of the system is a customized digital device
(LSI) which performs all the logic functions.
•It operates under the control of a clock frequency of
71.68khz obtained from a crystal oscillator which provides various timing and
control signal.
•The drop sensor is attached to the administration set
drip chamber and closes the servo loop by providing rate feedback information.
•The drop sensor contain an array of light emitting
diodes and phototransistor which generates a signal each time a drop of IV
fluid falls in to the drip chamber.
•Four signals are required to activate and run the motor.
•ALA, ACM, MD2,MD3.
•These signals except ALA are developed within the LSI
device. ALA is a logic 1 when the unit
is not in alarm.
•ACM provides power to the motor.
•ACM is designed to step the motor 10 ½ times for each
drop.
This is a Basic idea on Infusion pumps .If you have any doubts then you can ask me at ashutoshdas8@gmail.com or just make a comment here .
