Intravenous (IV) therapy is a standard medical procedure used to deliver fluids, medications, and nutrients directly into the bloodstream. While generally safe, this method carries the risk of complications, with IV infiltration being one of the most common issues encountered by patients receiving care. IV infiltration occurs when the solution being infused accidentally leaks out of the vein and into the surrounding soft tissue. This complication requires prompt attention to prevent discomfort and potential injury.
The Mechanism of IV Infiltration
IV infiltration happens when the catheter, or small tube, inserted into the vein either punctures the vein wall or slips entirely out of the vessel. The infusate (the fluid or medication) then flows into the interstitial space—the tissue surrounding the vein—instead of following the intended path through the bloodstream.
This accidental redirection often results from mechanical issues at the insertion site. Common causes include patient movement or jostling of the limb, which can dislodge the catheter tip. Vein fragility, often seen in older adults or those with certain medical conditions, can also lead to the vein wall rupturing under the pressure of the infusion. Additionally, infiltration can occur if the catheter is inserted incorrectly, such as penetrating the opposing side of the vein.
Recognizing the Signs and Symptoms
Identifying an IV infiltration quickly is important for minimizing discomfort and potential tissue damage. The most noticeable sign is swelling or puffiness around the intravenous insertion site due to the accumulation of leaked fluid in the surrounding tissue. This swelling can cause the skin to feel taut or tight.
The area may also feel noticeably cool to the touch, caused by the infusion of room-temperature fluid into the subcutaneous tissue. Patients frequently report localized pain, tenderness, or discomfort at the site. Other observable signs include a noticeable slowing or complete cessation of the fluid flow in the IV tubing, and the skin around the site may appear pale or blanched.
Immediate Response and Treatment Protocols
Immediate and appropriate action upon recognizing infiltration is necessary to limit the extent of the complication. The first step involves stopping the IV infusion immediately to prevent any further fluid from leaking into the tissue. Next, the intravenous cannula must be removed carefully from the vein.
Once the catheter is removed, the affected limb should be elevated above the level of the heart, if possible, to encourage the reabsorption of the leaked fluid and reduce swelling. The application of a warm or cold compress is generally recommended, although the choice depends on the type of fluid that infiltrated. For most non-vesicant solutions, a warm compress is preferred as it promotes vasodilation, which aids in the dispersal and reabsorption of the fluid. Conversely, a cold compress is sometimes used to reduce inflammation and pain, particularly in the initial 24 hours. The site must be closely monitored for improvement or any worsening of symptoms, and pain relief medication may be administered if the patient is experiencing significant discomfort.
Understanding Extravasation: A Critical Distinction
While often grouped together, infiltration and extravasation are distinguished by the type of solution involved. Infiltration refers to the leakage of non-vesicant solutions, which are fluids that do not typically cause severe tissue irritation or damage. These non-vesicant fluids include common solutions like normal saline or certain antibiotics.
Extravasation is a far more serious type of infiltration that occurs when a vesicant drug leaks into the surrounding tissue. Vesicants are agents capable of causing blistering, severe chemical irritation, tissue necrosis, or death of the soft tissue. Examples of vesicant medications include certain chemotherapy agents, high-concentration dextrose solutions, and some vasopressors. The management of extravasation is often more aggressive, sometimes requiring the injection of an antidote directly into the affected area to neutralize the chemical agent.