Intravenous (IV) therapy delivers fluids and medications directly into a patient’s bloodstream. This method carries the risk of complications if the IV catheter fails to remain securely within the vein. When fluid intended for the bloodstream leaks into the surrounding soft tissue, it creates a localized problem. These complications are categorized as infiltration or extravasation. The fundamental difference lies in the chemical nature of the leaked fluid, which determines the severity of the tissue damage.
The Core Distinction: Fluid Type and Tissue Damage
The distinction between infiltration and extravasation depends entirely on whether the leaked substance can damage tissue. Infiltration occurs when a non-vesicant solution, often called a non-irritant, leaks into the tissue around the insertion site. Non-vesicant fluids are benign substances like normal saline (0.9% sodium chloride) or dextrose solutions (D5W). When these fluids leak, the surrounding tissue absorbs the fluid relatively easily.
Extravasation, by contrast, is the leakage of a vesicant solution, which causes severe chemical irritation, blistering, and tissue death (necrosis). Vesicant agents include certain chemotherapy drugs, high-concentration electrolyte solutions, and some antibiotics. These substances actively injure the cells and structures of the surrounding tissue, leading to a much more serious injury than simple fluid overload.
The severity of the outcome differentiates the two conditions. Infiltration, while uncomfortable, rarely results in long-term consequences because the fluid is harmless and reabsorbs over time. Extravasation, however, can lead to permanent damage, including deep tissue sloughing, nerve damage, or the need for surgical debridement or skin grafting. The difference is a measure of the inherent toxicity of the substance that has escaped the vein.
How to Spot the Problem: Signs and Severity
Recognizing the onset of either complication is crucial, as observable signs reflect the underlying difference in fluid toxicity. Infiltration signs are localized and relate to excess fluid accumulation. The patient typically notices swelling or puffiness around the IV site, and the skin often feels cool to the touch. The IV infusion flow rate may also decrease or stop entirely because the catheter tip is no longer positioned correctly.
Symptoms of extravasation include swelling but are characterized by much greater severity. The patient often reports sudden, severe, and burning pain at the site, resulting from the vesicant substance irritating the nerves and tissue. The skin may initially blanch (turn pale), but later can show blistering, ulceration, or dark discoloration indicative of necrosis. This rapid progression, particularly the intense pain and blistering, signals the tissue-destructive nature of the leaked fluid.
Immediate Management and Treatment Protocols
The immediate response to either complication is stopping the infusion immediately to prevent further leakage. Subsequent treatment protocols diverge significantly based on the suspected condition. For a suspected infiltration, after the catheter is removed, the approach is to promote fluid reabsorption. This involves elevating the affected limb above the heart to encourage venous and lymphatic drainage.
Warm compresses are often applied for infiltration, as the heat encourages vasodilation, which helps disperse the non-irritant fluid into the surrounding circulation. In contrast, extravasation management is an urgent matter involving distinct steps to counteract the vesicant’s toxic effects. For extravasation, the catheter is sometimes left in place initially to attempt aspiration of the remaining drug from the subcutaneous tissue before removal.
The application of thermal compresses depends on the specific vesicant drug, but cold compresses are often used to cause vasoconstriction, localizing the toxic agent and reducing its spread. Specific antidotes, such as hyaluronidase, may be injected into the site to neutralize or speed the breakdown of the leaked drug. Extravasation requires close monitoring and may necessitate consultation with specialists to determine if surgical intervention is required to manage damaged tissue.