Infiltration and extravasation both involve IV fluid escaping into the tissue around a vein. Phlebitis is inflammation of the vein itself. In the terminology commonly taught in nursing, infiltration refers to leakage of a nonvesicant fluid, while extravasation refers to leakage of a vesicant, a substance that can blister or damage tissue. The site may look similar early on, so finding out what was infusing matters as much as describing what you see.
Consider a simulation: a patient says their peripheral IV site stings, and the skin next to the dressing looks puffy. You can report those changes right away. You don't need to settle on a diagnosis before getting the supervising nurse. The next question is what was running through that line, because the answer can change the urgency and the response.
What changes in each complication?
| Complication | Clues you might notice |
|---|---|
| Infiltration | Puffiness, cool or tight skin, or fluid near the dressing. |
| Extravasation | Swelling, burning, stinging, or color changes. |
| Phlebitis | Warmth and tenderness along the vein, sometimes with a firm cord. |
The Open RN nursing skills text uses the nonvesicant/vesicant distinction. Some hospitals use extravasation more broadly for fluid leakage and then assess risk by the substance involved. The Royal Children's Hospital's peripheral IV guideline is an example. Its guidance also distinguishes phlebitis caused by mechanical irritation, chemical irritation, or infection. In practice, use your facility's terms and report the findings and infusate so everyone knows what you're describing.
Infiltration: think about where the fluid went
With a peripheral IV, fluid should enter the vein. When fluid collects in nearby tissue, the area can swell or feel tight. Coolness can be a clue, but its absence doesn't rule out a leak. Nonvesicant doesn't mean harmless: pressure from accumulated fluid can still injure tissue. Notice the extent of swelling and whether it's changing rather than assuming that a routine fluid makes the problem minor.
Extravasation: find out what was infusing
You may see the same puffiness or discomfort with extravasation that you see with infiltration. What changes the concern is exposure to a substance that can injure tissue. The severity depends partly on the agent and the amount that escaped. Royal Children's Hospital's extravasation guidance notes that findings can develop hours later. A site doesn't have to blister before you raise the concern.
Phlebitis: follow the pattern along the vein
Tenderness that tracks along the vein with warmth makes vein inflammation a possibility. A firm vein may be palpable, but that isn't required. Some swelling and redness can occur with leakage, too, so a single finding doesn't settle it. Drainage that looks like pus or other signs of infection need prompt attention; phlebitis itself doesn't always mean an infection.
Assess the site, even if the pump is quiet
The Royal Children's Hospital guideline pairs looking and feeling with comparison to the opposite side. In a supervised clinical setting, describe where the swelling or tenderness starts, how far it extends, and how the skin feels compared with the other limb. Ask what the patient noticed and when. Check which fluids or medications were given through that line recently, including the one currently running.
An occlusion alarm can prompt a site check, but its absence isn't evidence that the fluid is reaching the vein. The Pennsylvania Patient Safety Authority's pump advisory explains why pressure alarms don't reliably detect fluid collecting in tissue. Look at the site and listen to the patient even when the display seems normal.
What to say and do when you suspect a leak
In supervised clinical practice, a suspected leak calls for stopping the infusion and getting help promptly under facility policy. If extravasation is possible, don't flush the IV or pull the catheter out reflexively. The team may need the catheter in place briefly to withdraw residual medication. The eviQ extravasation procedure illustrates this distinction for anticancer drugs and contrast media. Your facility's protocol and supervising team determine the next steps for the agent involved. Escalate rapidly worsening pain or swelling, numbness, or signs of reduced circulation immediately.
A useful simulation handoff might sound like this:
“There's new swelling around the left forearm IV. The patient reports burning that began during the infusion. The infusion is stopped. I haven't flushed or removed the catheter. Doxorubicin was infusing. Can you assess the site with me now?”
Include the exact medication or fluid name when known. If the agent or the amount that escaped is unclear, say so; don't guess or wait for a precise estimate to get help.
Check your reasoning
- The forearm gets puffy and feels cooler while a known nonvesicant fluid is running. Suspect infiltration. The clue is swelling in surrounding tissue together with the known fluid type.
- The same puffiness appears during a vesicant infusion, without blisters. Suspect extravasation. The agent changes the concern even though the site doesn't look much different yet.
- The site is tender, with a warm track running along the vein. Consider phlebitis. The location of the tenderness points toward vein inflammation, but the team still needs to assess for overlapping signs.
For a wider pharmacology refresher, see GoodNurse's guide to medication administration routes.
This nursing study guide was prepared with AI assistance, and its cover was AI-generated. Use your instructor's guidance and your facility's policy in clinical practice.
