What is a catheter?
A catheter is a thin tube usually made of a soft, flexible plastic. This medical device is used for the drainage of fluids that can be inserted into or removed from the body. Due to the large number of possible uses for this type of device, there are different types of catheters according to different medical societies.
What is a catheter used for?
Urinary catheters are used to drain urine from the bladder in patients who have trouble urinating or have poor bladder control.
Intravenous or intravenous (IV) catheters are used to deliver medications or fluids directly into the blood or to measure blood pressure in an artery. They may also be connected to a dialysis machine to filter waste materials from the blood if the kidneys are not working.
Catheters can also be threaded into the heart through an artery or vein to diagnose or treat certain heart conditions. Cardiac catheterization, for example, can be used for the following diagnoses:
- Look for heart valve problems.
- Angiogram (locate narrowing or blockage of blood vessels that may cause chest pain).
- Measure blood pressure and oxygen levels in the heart.
- Perform a biopsy by removing a tissue sample from the heart.
- Diagnose congenital heart defects.
They may also be useful for the following treatments:
- Angioplasty.
- Closing the septum of congenital ventricular septal defect (heart murmur).
- Replacement or repair of heart valves.
- Catheter ablation for arrhythmias.
- Closing parts of the heart to prevent blood clots.
Types of catheters
Urinary catheters
- Intermittent catheterization: These are temporary catheters that are inserted several times a day to drain the bladder through the urethra (the tube that carries urine from the bladder out of the body).
- Indwelling (Foley) catheters: These are long-term catheters that remain in the urethra for days or weeks, held in place by an inflated balloon at the end of the bladder. Urine is drained into a bag attached to the patient’s leg or bed while he or she sleeps. An indwelling catheter prevents the catheter from being inserted several times a day, but carries a higher risk of infection. It needs to be replaced every few months.
- Subrapubic catheters: This type of catheter is inserted into the bladder through a hole below the umbilicus rather than into the urethra. The procedure to install it can be performed under general, local or epidural anesthesia. Usually performed when the urethra is damaged or blocked.
Intravenous catheters
- Peripheral venous catheter: The simplest and least expensive of all, it is a short-duration intravenous line inserted into a vein in the hand, forearm or foot, and must be replaced by a nurse every few days.
- Central venous catheter: Inserted in an arm, leg, neck or chest, to connect to a vena cava leading to the heart. Central venous catheters are used to administer medications to patients with long hospital stays and who may stay for months or years. They can be used in treatments such as chemotherapy, dialysis or to administer nutrients to patients who cannot take food.
Cardiac catheterization
- Cardiac catheter: These are long catheters that are inserted through veins or arteries and advance through these blood vessels until they reach the heart. Their use can be useful for diagnosis or treatment, stenting or ablation of cardiac tissue.