Infusion Pump Working Principle

Infusion Pump

In the field of Medical sciences, infusion pump plays a significant role. The human body is just like a machine. Sometimes, it requires an artificial infusion of nutrients that keeps the body in a balanced state, and this requires a device to inject the supplements into the body. An infusion pump is a gadget used for medical purposes, which provides insulin doses, medications, and nutrients that the body requires at predetermined intervals. It controls the flow of infusion very accurately to ensure the amount of fluid required is evenly distributed in the body. An infusion pump is highly recommended for patients who require a set infusion dose at regular intervals over a long period of time.

What is an Infusion Pump?

A medical device called an external infusion pump is used to carefully administer fluids to patients. Infusion pumps come in a wide variety of designs and are employed in a wide range of settings and for a wide range of applications. They can supply fluids in large or small amounts, and they can be used to deliver nutrition or pharmaceuticals, including antibiotics, chemotherapeutic drugs, insulin or other hormones, and painkillers. Infusion pumps are primarily kept beside the patient’s bed for stationary use. Some infusion pumps are portable, and they are called ambulatory infusion pumps.

Infusion Pump animated

A Brief History

The evolution of modern infusion pumps used in hospitals is possible due to the significant contributions of some of the major scientists in the past years. Infusion pumps brought efficacy in the earlier Intravenous (transfusion within the veins) therapy that dates back to the Middle Ages. Sir Christopher Wren, an Oxford scientist created the first infusion device in 1656 by using a pig’s bladder and a writing quill, which made him earn the title of “Father of Intravenous Therapy.” The limitation of Wren’s invention was that it lacked longevity and required a lot of security. Johann Major was the first scientist to successfully inject people in 1662. He made possible the infusion of both blood and drugs into the human body, but his infusion method also resulted in several deaths due to infections at the infusion site. In 1665, Richard Lower experimented with the infusion of blood from one animal to save the life of another animal. Two years later, a 15-year-old child had lamb’s blood infusion from Jean Baptise Denis, a physician to King Louis XIV. This was a successful attempt, whereas this same treatment failed in another person who died after the transfusion. In the 1830s, Dr. Thomas Latta discovered that the injection of salty water into a patient’s bloodstream was fruitful against cholera; however, during the same period, Dr. James Blundell established the danger of transfusing animal blood into the human body and clarified through his laboratory results that only human blood is safe for transfusion. Infusion therapy made significant strides in 1914, and it was found that blood coagulation could be prevented by sodium citrate. In 1925, dextrose was employed as an infusant.

Infusion Pumps timeline

Infusion equipment shifted from open containers to glass bottles that were vacuum-sealed in 1930. Nurses were given the go-ahead to administer infusions ten years later. Infusions could only be carried out by doctors before 1940. By 1960, Infusion pumps had become a standard in all hospitals.

In the early 1960s Dr Arnold Kadish developed the first insulin pump, which was the size of a marine backpack

In the early 1960s Dr Arnold Kadish developed the first insulin pump, which was the size of a marine backpack

Parts of the Infusion Pump

Power supply system

A regular check of voltage (110 or 220 V) is required along with the consideration of AC or DC if the pump is connected using a rechargeable battery or to an external source. A voltage stabilizer is needed to reduce overloads or it can be connected to an appropriate transformer.

Ultrasonic air detector

It is a device that uses ultrasound to detect vacuum or air bubbles in a system.

Detachable peristaltic pump

It reduces the likelihood of incorrect connection and use between the system and a patient.

Door Lock

This is a safety anti-opening door. It doesn’t allow the medication to flow out during the infusion.

Pressure Adjustment

It is used to adjust the pressure of infusion as per the requirement.

Pressure Indicator

It indicates the infusion pressure.


It ensures the discharge of a fixed amount of medication or nutrients at a given time.

Number Lock

It helps in preventing the infusion settings from unauthorized changes.

SMS Alarm

This part is essential in showing messages or alarms if the machine faces any problem.

Infusion volume

It displays the infusion volume.

Drop/Flow Rate

It is used for showing the flow or rate of infusion.

Parts of an infusion pump


Infusion Pump Working Principle

The working principle of an infusion pump involves the combination of two methods known as the quasi-peristaltic process. The system uses a three-chambered cassette, which is used with an operating pumping mechanism. The user can choose a fluid delivery rate in milliliters per hour (ml/hr) along with the amount of fluid that should be transmitted in milliliters (ml). To protect the patient, the pump will not deliver fluid above a specified delivery pressure. This is accomplished by observing the pressure in the reservoir and setting a limit and making sure it doesn’t go over a specific level. Pumping stops if the pressure is surpassed. This is informed by an alarm sound known as an occlusion alarm. The pump’s operation is continuously monitored, and if something goes wrong, such as when fluid isn’t delivered as predicted, an alert will sound to protect the patient. The infusion pump contains a battery backup so that it can keep running even if the power goes out.

Infusion pump working principle

How to operate an Infusion Pump

The initial step includes attaching the pump to the IV pole stand, connecting to the ac power, connecting the plug of the drop sensor (optional item), turning on the unit, and then turning off the unit.

Infusion pump function

To operate the device, these steps need to be followed:

  • Connect the IV set to the container holding the solution.
  • Up to one-third of the solution needs to be filled into the drop chamber.
  • Make a drop of the solution that has formed on the tip of the needle by releasing the manual roller clamp on the IV set.
  • To expel air from the tube, keep pressing the [PURGE] button.
  • Close the manual roller clamp after the priming process is finished.
  • Attach the tube to the pump.
  • Close the door.
  • Attach the drop sensor.
  • Setup flow rate (ml/h).
  • Set up the delivery volume (ml).
  • Confirm total infused volume (∑ml).
  • Set up delivery time (hour).
  • Open the manual roller clamp on the IV set.
  • Put a needle into the patient’s body.
  • Start infusion and when it’s completed, stop the infusion.
  • Press the [power] button to turn off the unit.

Types of Infusion Pumps

Enteral pump

This is a device that infuses liquid drugs and nutrients into a patient’s digestive system.

Patient-controlled analgesia (PCA) pump

This pump administers painkillers and has a feature that enables patients to self-administer a prescribed dose of medication as necessary.

Insulin pump

This pump delivers insulin to diabetic patients.

Infusion Pumps

Functions of Infusion Pumps

Infusion pumps can be manually or electrically driven. Different pumps function in various ways.

Syringe pump

Fluid is kept in a syringe’s reservoir and delivered through a movable piston in a syringe pump.

Elastomeric pump

A flexible balloon serves as the reservoir for the fluid in an elastomeric pump, and pressure exerted by the balloon’s elastic walls drives fluid delivery.

Peristaltic pump

A set of rollers in a peristaltic pump pinches down on a section of flexible tubing to force fluid ahead.

Multi-channel pump

Fluids can be delivered from many reservoirs and at various rates using a multi-channel pump.

Smart pump

It has safety measures including user alerts that go off when there’s a chance of a drug interaction going wrong, or when the user changes the pump’s settings outside of the predetermined safety restrictions.

Advantages of an Infusion Pump

  • When compared to manually administering fluids, infusion pumps have several benefits including controlled infusion at precisely programmed rates or automatic intervals.
  • They can carry nutrients or medicines, including antibiotics, chemotherapeutic treatments, hormones like insulin, and painkillers.

Limitations of the Infusion Pump

  • The infusion pump may contain software issues as it works in a very systematic way. For instance, if a user codes a 10 mL/hour infusion rate, the device may record a 100 mL/hour infusion rate.
  • Sometimes a false alarm may occur.
  • An inadequate user interface design.
  • There can be battery failures.
  • Fire, sparks, charring, or shocks may occur.

Applications of Infusion Pumps

  • Infusion pumps are helpful during and after surgery and in the diagnoses of patients.
  • It provides intravenous discharge of nutrients to pediatric patients quite effortlessly for their growth, recovery, and survival.
  • An infusion pump is of great help during the delivery of anesthetics at the time of surgery and chemotherapy to cancer patients.
  • It is also helpful in the infusion of oxytocin hormone at the time of labor and the transportation of drugs in the coronary units.

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