By Dr Ananya Mandal, MD
Medical catheters are tubes that can be inserted into a body cavity, vessel or duct, usually to allow for the administration of fluids, medications or gases or to drain fluids or urine from the body. Examples of some types of catheter include intravenous catheters, urinary catheters and chest drainage tubes.
Some of the uses of catheters include:
Catheters used for this purpose are called Foley's catheters. The catheter is inserted into the bladder where it is held in place by a balloon filled with sterile water. Urine drains through the catheter into a bag that can be emptied. It may be used in cases of urine retention, interrupted urine stream, straining on urination, obstructed urethra or for the monitoring of urine output in a critically ill patient or after surgery.
In a procedure called percutaneous nephrostomy, catheters may be used to drain urine from the kidney.
Catheters may be used to drain fluid and pus that is collecting in cavities. For example, they may be used to drain pus from an abdominal abscess.
Catheters are used for intravenous fluid and drug administration. A fine, thin tube is inserted into the vein to deliver fluid or medication to the patient.
Infusion pumps are connected to catheters to deliver medications to patients, for example to deliver chemotherapy to cancer patients or insulin to diabetic patients.
Central venous catheters are large tubes that are placed directly into large veins in the neck or into the atrium of the heart to deliver medication or fluids. In sick newborns, an umbilical line may be created for delivering medication and fluids.
Cardiovascular procedures such as angioplasty, angiography and balloon septostomy all use catheters. A catheter is inserted into a vein in the groin and threaded into the heart under the guidance of X-ray imaging.
Catheters used in cardiology procedures may be designed to measure blood pressure in an artery or vein at specific locations in the body. The Swan-Ganz catheter is a special type of catheter placed into the pulmonary artery for measuring pressure in the heart. These can also be used for the direct measurement of pressure within the brain.
Catheters are used in regional anesthesia such as spinal and epidural anesthesia. The catheter can deliver anesthetic medication into the epidural space, the subarachnoid space, or around a major nerve junction in order to numb or paralyze certain locations.
Catheters called Quinton catheters are used in dialysis to treat patients with chronic kidney disease or renal failure.
Reviewed by Sally Robertson, BSc