Infusion pump

From ArticleWorld

An infusion pump is a medical machine that can administer fluids on a predictable basis to a patient’s system via a subcutaneous, intravenous, epidural or arterial route. Along with fluids, medications and nutrients can be provided as well.

Infusion types

A continuous infusion requires a pump that is set to pulse into a fluid line. The healthcare provider sets a rate at which the fluid is delivered. This is a commonly used type of infusion in the administration of IV fluids.

Intermittent infusion can be programmed to temporarily set a high flow rate that keeps the cannula open and is often used to provide boluses of medicine for short periods of time. Total parenteral nutrition (TPN) is also programmable and is timed to provide nutrition at higher levels during set mealtimes.

Patient-controlled infusion is a type of bolus infusion that is determined by the patient and his or her symptoms. This is often paired with a continuous low infusion of pain medication that is then temporarily increased by the patient, who pushes a button to release a preset bolus of medication for better pain control.

Pump operation

Two types of external infusion pumps are available. For large amounts of nutrients or fluids, a large volume pump is often required. Small infusion pumps are used to deliver tiny amounts of drugs, such as insulin, pain medications or hormones.

Larger pumps use peristaltic rollers to propel the fluid through the tubes containing fluid. In cases where high flow is required or in some blood transfusion cases, a cuff, not unlike a blood pressure pump, is placed around the bag of fluid and forces fluid or blood out of the bag at a higher pressure than surrounding air pressure. In the battlefield, this is a common method of providing high-flow fluid.

Low fluid pumps use a computerized device that controls a screw that slowly forces fluid through a syringe. A device like this might be used in a cardiac test called a dobutamine stress test, where the patient receives a small, steady flow of medicine that is put inside a syringe and causes the patient’s heart race for a small period of time. When the syringe is completely empty, the medicine is delivered and the effects wear off over a few seconds.

Osmotic pumps are low flow pumps and are quite small. It consists of a bag of salt water that absorbs water gradually and swells while medicine is pressed out. The pump volume and the salt concentration control the flow of medicine to the patient.

Safety

Almost all infusion pumps have safety features that sound alarms if the bag is empty, if the line is somehow disconnected or blocked in some way. In some cases, the pump stops altogether if an error is detected. Pumps that operate on battery can also be set to send an alarm when the battery wears out. If too much air is in the line, a pump will often register this and stop until the air is forced out of the line manually.