Intravenous (IV) therapy delivers fluids and medications directly into the bloodstream through a catheter placed in a vein. A recognized complication is infiltration, which occurs when a non-vesicant solution leaks out of the vein and into the surrounding subcutaneous tissue. Non-vesicant fluids, such as normal saline, do not typically cause severe tissue damage. This leakage happens because the catheter tip is no longer correctly positioned within the vessel lumen, diverting the infused fluid into the space beneath the skin.
Circumstances Leading to Infiltration
Infiltration is a mechanical failure caused by the catheter moving or damaging the vein wall. The most common cause is physical dislodgement due to inadequate securement. If the stabilization dressing fails, the catheter can shift, causing the tip to back out or puncture the opposing vessel wall.
Patient movement is also a significant factor, especially when the IV is placed near a joint like the wrist or elbow. Flexion and extension of these joints can repeatedly stress the catheter, causing the tip to erode the vein lining or push through the wall. Incorrect insertion technique can also cause immediate infiltration if the clinician punctures both the front and back walls of the vein.
The condition of the patient’s veins plays a role, as fragile or compromised veins are more susceptible to damage. Veins that are small, scarred, or weakened by chronic illness are more likely to rupture under the pressure of the infusing fluid. Increased pressure within the vein, perhaps due to a small clot, can also force fluid backward through the puncture site.
Timeline of Recognition and Progression
Infiltration can occur at any point during IV therapy, ranging from an immediate event to a gradual development over hours or days. Immediate onset often happens during the initial insertion process or shortly after securing the site. Leakage begins instantly if the catheter tip punctures through the vein wall while the needle is withdrawn, or if a fragile vein ruptures under the force of the initial flush.
A more gradual onset is common when infiltration is caused by slow erosion of the vein wall or minor catheter movement. In these scenarios, the catheter tip may slowly migrate, rubbing against the lining until a small hole develops, allowing fluid to seep out over several hours. This delayed leakage may not be noticeable until a considerable volume has collected in the tissue.
The severity of infiltration progresses through distinct stages. Early-stage infiltration involves localized swelling and coolness confined to the insertion site. As more fluid accumulates, the infiltration progresses to advanced stages, characterized by significant swelling extending beyond the site, increased pain, and a stretched or taut appearance of the skin.
Identifying Signs and Symptoms
Recognizing infiltration relies on observing specific physical changes at the IV site and monitoring the infusion system. The most common physical sign is swelling or puffiness around the catheter insertion point, caused by IV fluid pooling in the subcutaneous space. This swelling often makes the skin appear taut and shiny.
The affected area also feels noticeably cool to the touch compared to the surrounding skin, a direct result of the room-temperature IV fluid collecting beneath the surface. Patients may report pain, tenderness, or a burning or stinging feeling at the site, caused by the pressure of the accumulating fluid.
Objective signs related to the IV system also point to infiltration. The infusion rate may slow down significantly or stop completely because the fluid meets resistance in the compressed tissue. If the infusion is running via a pump, the device may trigger a high-pressure alarm as it attempts to overcome the resistance created by the fluid accumulation outside of the vein.
Immediate Steps and Prevention
When infiltration is suspected, the immediate action is to stop the flow of the IV fluid and gently remove the catheter to eliminate the source of leakage. After removal, the affected limb should be elevated above the level of the heart to promote reabsorption of the leaked fluid and reduce swelling.
Specific care, such as applying a warm or cold compress, depends on the type of fluid infused. A warm compress is generally preferred for non-vesicant solutions because the heat helps dilate local blood vessels, assisting the body in dispersing the fluid more quickly. The site should be monitored closely for any worsening symptoms.
Preventative measures focus on meticulous procedural technique and consistent site assessment throughout the duration of the therapy. Key preventative steps include:
- Selecting an appropriate IV site, ideally in a straight section of the vein away from joints, to minimize mechanical failure.
- Proper securement of the catheter with a sterile dressing and tape to prevent dislodgement or migration.
- Regular, frequent monitoring of the insertion site, particularly in the first few hours of a new infusion, for early detection.