Intravenous (IV) therapy is a cornerstone of modern healthcare. IV access allows healthcare professionals to administer medications, fluids, and vital nutrients directly into a patient’s bloodstream.
Both central lines and midline catheters are types of vascular access devices, but they aren’t the same thing. A peripherally inserted central catheter, or PICC line, is a type of central venous catheter used for longer-term therapies. Midline catheters are peripheral catheters that are used when IV therapy is needed for more than five days but less than a few weeks.
So, what’s the difference between a central line and a midline? And how do healthcare providers decide which one is best? The answer depends on how long IV therapy will be needed, what kind of medication is being administered, and how irritating that medication might be to the veins.
Central Lines and Midline Catheters: What’s the Difference?
Both central lines and midline catheters are intravenous (IV) lines. However, they have key differences in terms of where they’re placed, what they’re made of, and what they’re used for.
Central Lines (Including PICCs)
Central lines are inserted into large, central veins near your heart, such as the superior vena cava (SVC) or the inferior vena cava (IVC). A peripherally inserted central catheter (PICC) is a type of central line that’s inserted into a vein in your arm and then threaded up to one of those central veins.
These lines are made of biocompatible materials like polyurethane or silicone and come in a variety of sizes and configurations, including single-lumen and multi-lumen.
Central lines are good for long-term IV therapy, lasting from weeks to months and sometimes even a year. They’re often used to administer medications that could damage smaller veins (vesicant medications), to provide nutrition through a vein (parenteral nutrition), and to draw blood frequently.
Midline Catheters
Midline catheters are inserted into peripheral veins in the upper arm, such as the basilic, cephalic, or brachial veins. However, the tip of the catheter doesn’t extend as far as a central vein; it stops before it reaches your armpit.
Midlines are usually made of the same materials as central lines, but they’re shorter in length, typically between 8 and 25 centimeters.
Midline catheters are useful for short-term therapies lasting from one to four weeks. They can be used to administer medications that aren’t likely to irritate or damage the vein.
Advantages and Disadvantages of Central Lines (PICC Lines)
PICC lines can be a great option for some patients, but they also come with a few potential downsides. Here’s a rundown of the pros and cons:
Advantages
- Versatile medication administration. PICC lines can handle a broad range of medications, including those that might irritate smaller veins. This is because the larger vein helps dilute the medication quickly.
- Long-term use. These lines are designed to stay in place for weeks or even months, which means fewer needle sticks and less disruption to your treatment.
- Reliable vascular access. If you have veins that are hard to find or access, a PICC line can provide a consistent and reliable way to administer medications or draw blood.
Disadvantages
- Higher risk of complications. Compared to midline or peripheral IVs, PICC lines carry a greater risk of bloodstream infections (called CLABSIs). There’s also a risk of venous thrombosis, or blood clots, especially in the arm.
- Insertion complexity. Inserting and maintaining a PICC line requires specialized training and expertise. Not all healthcare providers are qualified to do it.
- Cost. PICC lines are generally more expensive than midline catheters because of the specialized procedures and equipment required for insertion.
What are the advantages and disadvantages of midline catheters?
Midline catheters are a good option in some medical situations, but they’re not right for every patient or every treatment. Here’s a quick look at the pros and cons of using a midline catheter:
Advantages of midline catheters
- Lower risk of complications. Midlines are associated with a lower risk of central line-associated bloodstream infections (CLABSI) and venous thrombosis (blood clots) compared to central lines.
- Easier to insert. A trained nurse can usually insert a midline catheter using a fairly simple procedure.
- Cost-effective. Because they’re easier to insert and have a lower risk of complications, midline catheters are generally less expensive than central lines.
Disadvantages of midline catheters
- Limited medication options. You can’t use a midline catheter to administer vesicant medications or other highly irritating drugs.
- Shorter duration of use. Midlines usually aren’t used for therapies that will last longer than four weeks.
- Vein irritation. Certain medications or infusion rates can cause phlebitis (vein inflammation).
Clinical Considerations: Choosing the Right Catheter
Deciding between a central line and a midline catheter depends on a number of factors, including characteristics about you and your health, and the treatments you need.
Patient Factors
- Vein condition: The healthcare team should assess your peripheral veins to see if they’re in good enough condition to support a midline. Midlines are often a good choice for people who are hard to stick.
- Medical history: Your doctor will want to know if you’ve had infections or thrombotic events in the past.
- Home environment: Will you be able to manage the catheter at home?
Treatment Factors
- Duration of therapy: Midlines are generally used if you’ll need access for 1 to 4 weeks. If you’ll need IV access for longer than that, a PICC line is probably a better choice.
- Medication type: PICC lines are required for irritating medications or parenteral nutrition.
- Infusion rate and volume: The doctor will also consider how fast the medication needs to be delivered and how much fluid you’ll need.
Risk Mitigation Strategies
No matter which type of catheter you and your healthcare team decide is best, there are strategies you can use to lower your risk of complications.
- Infection prevention: Strict aseptic techniques should be used when the catheter is inserted and maintained. Chlorhexidine-impregnated dressings and regular dressing changes are also important.
- Thrombosis prevention: Staying mobile and hydrated can help prevent thrombosis. Your doctor may also prescribe a prophylactic anticoagulant if you’re at high risk.
Frequently Asked Questions
When do you use a midline catheter?
Midline catheters are great for when you need intravenous access for a bit longer than a regular IV, but not as long as you’d need a central line. Think treatments lasting a few weeks, like antibiotics or medications that aren’t too harsh on your veins.
What is the difference between a PICC line and a midline?
Both are inserted into a peripheral vein in your arm, but the key difference is where they end. A PICC (Peripherally Inserted Central Catheter) line goes all the way up to a large vein near your heart, while a midline stops in the upper arm, making it less invasive but also less suitable for certain medications.
What are the two types of central lines?
While there are a few ways to categorize central lines, think of them primarily in terms of insertion site. You’ve got central lines inserted through a vein in your neck (internal jugular), chest (subclavian), or groin (femoral). Each has its own set of pros and cons, based on infection risk and patient comfort.
Is central line the same as midline?
Nope, not at all! A midline is a type of peripheral intravenous catheter, meaning it’s inserted in a vein in your arm and stops there. A central line, on the other hand, is a central venous catheter, meaning it’s inserted either in your neck, chest or groin and ends in a major vein near the heart. Big difference in terms of placement and what they’re used for.
Key Takeaways
Central lines and midline catheters are both types of intravenous (IV) access, but they differ in insertion site, dwell time, and the types of medications they can deliver. Central lines go into a large vein near the heart, while midlines are placed in an upper arm vein.
The choice between a central line and a midline depends on the individual patient’s needs, treatment plan, and overall health. A thorough assessment is essential to decide which type of vascular access is most appropriate.
Ultimately, healthcare professionals play a crucial role in ensuring safe and effective IV therapy by selecting the right device, inserting it properly, and monitoring the patient for complications.