What is an Infusion Pump? | How does an Infusion Pump work?

An infusion pump is a medical device that uses to supply fluids or medications into the body of the patient. The infusion pumps began to be used in the late 1960s. These types of pumps deliver a controlled amount of nutrients and medications into the body of the patient. They may operate mechanically or electrically.

These devices mostly use in all medical applications for different treatments. Only a professional doctor can operate these pumps because only he knows how to program the fluid supply’s infusion time and flow rate.

An infusion pump is more effective than a manual injection pump because it can supply a controlled amount of liquids at an accurate frequency, interval, and volume. Compared to manual injection pumps, infusion pumps have the capability to supply minimal amounts of liquid and the capability to supply liquids at exactly programmed rates or at automatic times.

These pumps deliver medications such as insulin, antibiotics, a chemotherapy drug, and some other medications. These pumps almost use in all hospitals, especially in intensive care units, where they usually require a pump for each drug. You can also find infusion pumps at your nearest hospitals.

Infusion pumps are usually operated by skilled users who program infusion rates and fluid supply time via an integrated software interface.

The infusion pumps have many types according to the intended use and environment. Few types of infusion pump primarily manufacture for fixed use that attaches to the bedside of the patient. Other pumps, known as ambulatory infusion pumps, design in such a way that they can move from one place to another.  

Working of Infusion Pump

There are multiple types of an infusion pump that works in different ways. But the common type of infusion pump is a syringe pump, and here we will discuss the working of the syringe pump. A syringe infusion pump working in the following way:

infusion pump working

  • A syringe pump is a type of reciprocating pump that gradually delivers the exact volume of fluids such as medications or nutrients. A Chemyx Fusion series syringe pump drives by a stepper motor.
  • A guide screw is threaded via a push block. This guide screw uses to turn the stepper motor of the pump. This will move the push block.
  • As the pusher block pushes the plunger of the fixed syringe in the infusion pump mode, then the liquid expels at the precise speed.
  • The push block holder’s brackets secure the syringe plunger and offer a pull-out function.
  • As the stepper motor rotates in the opposite direction, the pusher block will move and pull the plunger of the syringe to draw the liquid into the syringe.
  • The pusher block moves toward the right side for infusions and left for withdrawals for Fusion series syringe pumps.

Types of Infusion Pump

The are multiple types of infusion pumps, but the most common types are:

  • Types according to the infusion pump’s function
  • Types according to the infusion pump’s mobility
  • Types according to the pump capability of the fluid volume delivery

types of infusion pump

1) Types according to the infusion pump’s mobility

i) Ambulatory Infusion Pump (AIP)

A small battery-operated pump slowly pumps medications such as antibiotics or chemotherapy into the patient body. These infusion pumps have a low weight that is often utilized to treat patients with debilitating problems. In rare cases, the debilitating patients have to move around with the medical infusion because they have to take medicine all over the day.  In such cases, the ambulatory infusion pumps having low weight assist in transporting a patient with his medication. This lightweight pump resolves the problems of medical infusion supply while on the go.

Ambulatory infusion pumps

Advantages and Disadvantages:

          Advantages           Disadvantages

These are moveable

These are not best for all medical applications

These pumps have lightweight


ii) Stationary Infusion Pumps

In contrast to an ambulatory infusion pump, a stationary infusion pump does not require a lightweight and compact design because it is a fixed pump and does not need to move. Chronically ill patients who are bedridden for long periods of time usually need diet or medication infusions.

These pumps supply bedside intravenous fluids to patients who frequently need bedside medication or nutrition. In contrast to ambulatory infusion pumps, stationary pumps have heavy weight.

Stationary infusion pump

Advantages and Disadvantages:

   Advantages           Disadvantages
Stationary pumps are best for delivering medicine inside the body of the patient in stationary form These are not moveable

These pumps have heavyweight


2) Types according to the pump capability of the fluid volume delivery

According to the fluid delivery capacity, the infusion pumps have the following two types:

i) Syringe Pumps

The syringe pump uses an automatically controlled electric motor to run a piston for medication provision. This piston of the syringe is made of plastic. The precise size of the syringe and its position is very important in the pump. This pump has the capability to supply a low volume of the drug that you want.

Mostly, the syringe pumps use to deliver a low volume of medications inside the body of young, babies, and older people.  These are the best pumps for delivering small doses of drugs such as hormones inside the patient body. The syringe pump delivers medicine via a controlled motor mechanism that utilizes a piston.

syringe Pump

Advantage and Disadvantages of Syringe Pump:


  • The syringe pumps deliver a precise volume of the medications.
  • These have a high distribution ability
  • This pump has an easy desktop placement
  • It produces very low pulsation of the flow
  • It has a small volume
  • The syringe pump has the capability to deliver a low amount of fluid inside the patient body.
  • It has a low cost disposable


  • It can’t deliver a very large amount of medications
  • It doesn’t have the latest technology like LVP, such as an alarming system.

ii) Large Volume Pump (LVP)

It is an infusion pump that can inject large amounts of medications and nutrients into the body of the patient. These pumps use to deliver large quantities of medications. In general, large volume pumps are the most modern version of the pumps and have innovative pumping features such as these have an alarm system in case something goes wrong. They also use one electronic peristaltic pump. The LVP controls via a computer-controlled roller or manual source.

Large volume pumps

Advantages and Disadvantages of LVP:

             Advantages             Disadvantages
These have the capability to deliver a large number of medications It needs large space for installation
LVP has the latest technology, such as it has an alarming system. If something will be wrong, then this alarm will start ringing. It has a large size

3) Types according to the function of the pump

According to the function and advancement of the infusion pumps, these have the following two major types:

i) Specialty Pump

These pumps are manufactured to meet the needs of special medical cases. Specialty infusion pump mainly uses for home care services or treating a specific disease (for example, diabetes). There are three types of specialty infusion pumps:

  • Insulin infusion pump
  • Enteral infusion pumps
  • Implantable infusion pump

ii) Conventional Infusion Pump

Conventional infusion pumps can be used for medical setting such as mobile, home, and long-term settings. These pumps may use in both mobile and stationary settings to deliver hydration fluids, chemotherapy drugs, antibiotics, and pain medicine. These pumps have further three types that are:

  • Elastomeric pump
  • Large volume pump
  • Disposable pump
  • Syringe infusion pump

Block diagram of Infusion Pump

infusion pump block diagram

The above illustration is a block diagram of a programmable infusion pump. It has a peristaltic pump mechanism. The transfusion rate (vol/min) is entered via the keyboard. An infrared detector senses the current rate of the drip.

The error between the desired drip rate and the current drip rate is measured and changes the stepper motor speed accordingly. Different errors such as empty drug bottles, low battery, door opening, air bubbles, etc., will show up as abnormal condition transfusions.

Alarms or LEDs indicate the visual and acoustic error display. The ZigBee module uses to send failure data to the host PC wirelessly. The transfusion monitor functions as a single device or as a slave node in a point-to-multipoint topology network of the distribution system.

Safety features of Infusion Pump

The safety features of the infusion pump depend on the life cycle and brand of the pump. A state-of-the-art pump for 2003 may have the below-given safety features:

  • No single point of failure has been certified. It means a single cause of failure should not result in the pump failing silently. It must pause pumping and at least provide an audible error warning. This is the lowest obligation for all injection pumps for people of all ages. This obligation isn’t compulsory for animal infusion pumps.
  • The pump should also have a battery so that it can work in case of power failure due to unplugging or some other reason.
  • The infusion pump should have an anti-free-flow device. Because when setting up an infusion pump, an anti-free-flow device stops blood from flowing out of the patient’s body and preventing the infusion from entering the patient’s body freely.
  • The pump should have a “down pressure” sensor. It detects the blockage veins of the patient or also detects the lines connected to the patient are kinked. It can configure for low (venous) or high (epidural and subcutaneous) functions.
  • An “air-in-line” sensor uses an ultrasonic transmitter and receiver to sense that air is being delivered or not. Some types of infusion pumps can calculate the volume and adjust the air volume to 0.1-2 ml. The air amount from 0.1 to 2 ml is harmless, but this amount of air can affect with the injection of low doses of the drug.
  • The “up pressure” detector uses to sense that either the syringe or bag is empty or tight due to the high volume of fluid.
  • A medication library with programmable, adaptable individual drug limit values ​​helps to avoid dosing errors.
  • Mechanisms to prevent uncontrolled drug flow in high volume infusion pump (generally used in combination with st-based free-flow clamps) and to increase drug flow in syringe pumps (piston brakes)
  • Many types of pumps contain an internal electronic log of the last thousand treatment events. They are usually time and date stamped from the pump clock. In general, log cleaning is a function that protects via a security code. It designs to identify any misuse of the pump or patient by staff.
  • Many brands of infusion pumps can configure to show only specific properties during their use to avoid tampering by patients, untrained personnel, and visitors.

How to use Infusion Pump

After giving a bedside presentation to the patient, review the patient’s medical history before infusing the medicine into the patient body. After that, follow the following steps to use an infusion pump:

  • First of all, note the medication type, amount of medication, and time of intake.
  • Check if the patient has an allergy.
  • Obtain consent from the patient
  • If the syringe or bag is contaminated, then don’t use it
  • Eliminate the packing of the medication bag
  • Hang this bag in the drip stand
  • Switch on the preset setting and switch off the flow control (with ball clamps)
  • Break the bag opening cap
  • Introduce the tip inside the port (don’t touch this tip)
  • Squeeze and release the ball clamp to discharge fluid from a specific device
  • Make sure there are no bubbles
  • Hold the ball
  • Wash your hands and wear an apron and gloves
  • Clean the connection hub with a cleaning cloth and flush the cannula with saline solution.
  • Link the supplied device to the biological connection
  • Set the infusion speed of the pump by moving the ball

Advantages and Disadvantages of Infusion Pump

Larger capacitySome kinds of infusion pumps have a high price
These pumps have an alarm system if
something goes wrong
It has a battery problem
Infusion warmingThis pump needs a battery for power
It is less irritativeA professionally trained person is required to operate this pump
Infusion pump has high flow ratesStaff training is needed
Easier needle-to-needle alarmsIn some cases, infusion pump causes infection
Less liquid type limitationsBecause it is software operated, therefore, this software may produce defects
LightweightElectrical or mechanical failure issues
These pumps have many types that use for different applicationsUser interface problems
Modular design

Applications of Infusion Pumps

  • These pumps utilize in cancer therapy when delivering chemotherapy
  • Uses in the medical pharmacies for injecting different medicines
  • These pumps use to inject various nutrients or medications inside the patient body
  • It improves the safety of the patient via increasing accuracy and consistency
  • It also uses for pain management

FAQ Section

What are the types of infusion?

The infusions have the following types:

  • Parenteral and enteral nutrition
  • Pain management
  • Antibiotics
  • Intravenous gamma globulin (IVIG)
  • Hemophilia factor therapy
  • Heart pump medication
  • Fluids
  • Chemotherapy
  • Biologics

What is an infusion pump used for?

An infusion pump has the capability to deliver a small or large amount of fluids. In addition, infusion pumps use to deliver nutrients or medicines (such as pain relievers, chemotherapy medicines, antibiotics, and insulins, etc.) inside the body of the patient.

What are the four major problems of infusion pumps?

An infusion pump has the following major problems

  • Battery problems
  • Electrical or mechanical failure issues
  • User interface problems
  • Software defects

See also:

  1. How does a Centrifugal Pump work?
  2. What are the types of Reciprocating Pumps?

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