A main line IV, more formally called a central venous catheter or central line, is a long, thin tube inserted into one of the body’s large veins and threaded until the tip sits near or inside the heart. Unlike a standard IV placed in the hand or forearm, a main line delivers medications and fluids directly into a high-flow vein where they’re diluted and distributed quickly. It’s used when a regular IV can’t do the job, either because the treatment is too harsh for small veins, too many infusions are needed at once, or access is required for weeks or months.
Why a Main Line Is Used Instead of a Regular IV
A standard peripheral IV works well for short-term hydration, common antibiotics, and pain medication. But certain treatments would damage smaller veins. Chemotherapy drugs, concentrated nutrition delivered directly into the bloodstream (called parenteral nutrition), and some strong medications are too caustic for the thin-walled veins in your arm. A main line places these substances into a large central vein where blood flow is heavy enough to dilute them immediately, protecting the vessel walls.
Main lines are also placed when doctors need to give multiple infusions at the same time that can’t be mixed together, when they need to monitor blood pressure inside the veins near your heart, or when your peripheral veins are simply too small, scarred, or collapsed to support a standard IV. Patients receiving dialysis, long courses of IV antibiotics, or extended cancer treatment are common candidates.
Where It Goes In
Three large veins are the typical targets. The internal jugular vein, which runs along the side of the neck, is the most commonly used because it’s relatively close to the surface, has predictable anatomy, and can be located easily with ultrasound. The right side is preferred when possible because it provides a straighter path down to the large vein above the heart.
The subclavian vein, which runs beneath the collarbone, carries lower risks of infection and blood clots. It’s also useful in trauma situations where a neck collar blocks access to the jugular. The femoral vein in the groin is a third option, often chosen in emergencies because the site is away from airway equipment and easy to compress if bleeding occurs.
Regardless of which vein is used, the catheter tip is advanced until it rests in the superior vena cava, inferior vena cava, or right atrium, the large chambers that funnel blood into the heart.
Types of Main Lines
Not all central lines look or work the same. The type your medical team chooses depends on how long you’ll need it and what treatments are planned.
- Non-tunneled central line: Inserted directly through the skin into a large vein. This is the most common type for short-term hospital use, typically days to a few weeks. It’s placed at the bedside and removed when no longer needed.
- PICC line (peripherally inserted central catheter): Threaded through a vein in the upper arm and advanced until the tip reaches the chest. PICCs are designed for medium-term use, commonly up to three months but capable of lasting up to six months. They’re popular for patients who need IV antibiotics at home.
- Tunneled catheter (Hickman or Broviac): Surgically placed so that part of the catheter runs under the skin before entering the vein. This “tunnel” helps anchor the line and reduces infection risk. These can stay in place for years and are common in cancer treatment.
- Implanted port: A small reservoir placed entirely under the skin, usually below the collarbone, connected to a catheter in a central vein. Because it’s fully hidden, a port is the most discreet option. Nurses access it by inserting a special needle through the skin into the port. Ports can last for years and are favored for patients receiving intermittent chemotherapy cycles.
What the Procedure Feels Like
For a bedside central line placement, you’ll lie flat and the insertion site will be cleaned and draped in sterile coverings. A local anesthetic is injected near the vein to numb the skin, which makes the insertion itself essentially pain-free. You may feel pressure or a pushing sensation as the catheter is threaded in, but sharp pain is uncommon. The entire process typically takes 15 to 30 minutes. Afterward, a chest X-ray confirms the catheter tip is in the correct position.
PICC lines and ports involve similar numbing but may be placed in a procedure room or interventional radiology suite where imaging equipment helps guide the catheter. Port placement is a minor surgical procedure, sometimes done under light sedation.
How a Main Line Is Maintained
Keeping a central line clean and functioning is critical. The line needs regular flushing with normal saline, a salt-water solution pushed through the catheter to prevent blood from clotting inside it. A standard flush uses about 10 milliliters of saline before and after medications. After thicker substances like blood products or parenteral nutrition, the flush volume doubles to 20 milliliters.
When the line isn’t actively being used, it’s “locked” with a small amount of fluid to keep it open. Short-term catheters are typically locked every 8 to 24 hours, while long-term tunneled catheters may only need weekly locking. Implanted ports that aren’t being accessed regularly are flushed every 6 to 8 weeks to maintain patency.
The dressing over the insertion site is changed regularly using a sterile technique. If you’re sent home with a PICC or tunneled catheter, a nurse will teach you or a caregiver how to flush the line, change the dressing, and recognize signs of trouble.
Infection Risk
The most significant risk of any central line is a bloodstream infection, known in hospitals as a CLABSI (central line-associated bloodstream infection). Because the catheter sits inside a major vein and connects to the outside environment, bacteria can travel along it and enter the bloodstream directly. Hospitals follow strict protocols to minimize this, including sterile insertion technique, daily assessment of whether the line is still needed, and careful dressing and site care.
These efforts have been paying off. According to CDC data, CLABSI rates dropped 9% nationally in 2024 compared to the prior year, with similar decreases in both ICU and general ward settings. Still, infection remains the primary reason medical teams remove central lines as soon as they’re no longer essential.
What Removal Looks Like
Removing a non-tunneled central line or PICC is a quick bedside procedure. You’ll be asked to lie flat, and the catheter is pulled out smoothly. The care team then covers the exit site with an airtight dressing and applies pressure for 5 to 10 minutes to stop bleeding and prevent air from entering the vein. You’ll typically stay lying down for about 30 minutes afterward as a precaution against air embolism, a rare but serious complication where a bubble of air enters the bloodstream.
Tunneled catheters and ports require a minor procedure to remove since part of the device sits under the skin. Recovery from port removal is minimal, usually just soreness at the site for a few days.