IV phlebitis is the inflammation of a vein specifically linked to an intravenous (IV) catheter. It is a common complication of IV therapy, which involves inserting a thin tube into a vein to deliver fluids or medications. IV phlebitis develops when the vein’s inner lining, the tunica intima, becomes irritated or damaged, manifesting as pain, redness, and swelling at or along the insertion site.
Mechanical Factors
A catheter that is too large for the chosen vein can cause friction and irritation against the vein wall, leading to mechanical phlebitis. Using the smallest appropriate catheter size helps minimize this risk.
The site where the catheter is inserted also plays a role in the likelihood of developing phlebitis. Locations prone to frequent movement, such as joints or areas of flexion like the wrist, can lead to the catheter rubbing against the vein and causing irritation. Avoiding these high-motion sites and opting for more stable areas, such as the forearm, can help reduce mechanical stress on the vein.
Trauma to the vein during the insertion process is another mechanical factor. Multiple attempts or an improper insertion angle can damage the delicate vein wall. If the catheter is not adequately secured, it can move within the vein, leading to continuous friction and inflammation. The catheter material can also influence irritation.
Chemical Irritation
The pH (acidity or alkalinity) of the infused solution is a significant factor. Solutions that are markedly acidic or alkaline compared to the body’s neutral pH can damage the vein’s inner lining, increasing inflammation risk.
Osmolarity, the concentration of dissolved particles in a solution, also impacts vein integrity. Solutions highly hypertonic (more concentrated) or hypotonic (less concentrated) than blood can cause fluid shifts across the vein wall, leading to irritation and damage. While blood plasma typically has an osmolarity around 290 mOsm/L, phlebitis risk increases significantly when infused solutions exceed 450 mOsm/L, with high risk above 600 mOsm/L.
Highly concentrated medications are inherently more irritating to the vein. Certain medications, including specific antibiotics like vancomycin, ciprofloxacin, and potassium chloride, and various chemotherapy drugs, are known for causing chemical phlebitis. Other examples include nicardipine, noradrenaline, amiodarone, and levetiracetam. Undissolved particulate matter within solutions can also contribute to vein irritation.
Infectious Agents
A breach in aseptic technique during catheter insertion or maintenance is a primary route for bacterial entry. If sterile procedures are not meticulously followed, bacteria can be introduced into the vein. Contaminated equipment or supplies can also introduce infectious agents.
Skin flora can migrate along the catheter and enter the insertion site if not properly managed. Inadequate cleaning or infrequent dressing changes create an environment where bacteria can multiply, increasing infection and phlebitis risk. If an infection develops, it can escalate to systemic sepsis if not addressed promptly.
Individual Susceptibility
The condition of a patient’s veins plays a significant role. Pre-existing vein damage, naturally small or fragile veins, or a history of numerous previous IV insertions can make veins more vulnerable to inflammation. Sclerosed veins, often due to prior IV drug abuse, also present a higher risk.
Patient age is another contributing factor, as both very young and elderly individuals may have more fragile veins or altered immune responses that heighten their risk. Underlying health conditions can also compromise vein integrity and the body’s ability to heal. Conditions such as diabetes, a compromised immune system, or peripheral vascular disease can increase susceptibility to phlebitis. Certain cancers also elevate the risk of thrombophlebitis.
Dehydration or poor nutritional status can further impact vein health, making veins more prone to injury during catheter insertion and inflammation. The duration an IV catheter remains in place is also a notable factor. Longer dwell times are associated with an increased risk of phlebitis and potential infection. Phlebitis can even appear 48 to 96 hours after catheter removal.