Intravenous (IV) therapy is a standard procedure used to deliver fluids, medications, and nutrients directly into the bloodstream. A common complication, often referred to as a “blown IV,” occurs when the catheter fails to remain properly seated within the vein. This failure causes the infused solution to leak into the surrounding soft tissue of the limb, which necessitates removing the line and reinserting it elsewhere, interrupting treatment and causing patient discomfort.
Understanding Infiltration and Extravasation
The clinical term for a “blown IV” is most commonly infiltration, which describes the accidental leakage of a non-irritating fluid into the interstitial space. This usually involves solutions like normal saline, certain antibiotics, or standard dextrose solutions. Infiltration occurs once the vein wall is compromised, allowing the solution to seep out.
A more serious event is extravasation, which is the same leakage mechanism but involves a vesicant or irritating solution. Vesicants are medications, such as certain chemotherapy drugs or vasopressors, that can cause significant tissue damage, blistering, and even necrosis if they escape the vein. Both complications share the same physical mechanism—a breach in the vein wall—but the severity depends entirely on the chemical nature of the infused substance.
Immediate Causes Related to Insertion Technique
One of the most frequent mechanical causes of IV failure is the catheter tip pushing entirely through the back wall of the vein during insertion. This error, sometimes called “back-walling,” immediately creates a second exit point for the fluid into the subcutaneous tissue. Even if the initial insertion is successful, an improper angle can cause the catheter to rub against the vein’s inner lining, or endothelium, leading to localized erosion over time.
A second major technical cause involves the catheter-to-vein ratio (CVR), which is the proportion of the vein’s diameter occupied by the catheter. Current guidelines suggest that the catheter should not occupy more than about 40 to 45 percent of the vein’s diameter. Selecting a catheter that is too large for the chosen vein restricts blood flow around the device, increasing the risk of mechanical phlebitis (inflammation) and thrombosis (clot formation).
Poor stabilization of the device following insertion is another factor that can lead to vein compromise. If the catheter is not securely taped or dressed, even small, unconscious movements by the patient can cause the rigid plastic tip to move within the vein. This micro-movement acts like a constant irritant, causing the catheter tip to eventually erode the delicate vein wall.
Pre-existing Factors Increasing Vein Vulnerability
Many patient-specific conditions increase the fragility of peripheral veins, making them more susceptible to failure. Chronic conditions like diabetes and chronic kidney disease (CKD) are known to compromise vascular health through long-term endothelial dysfunction. This damage results in increased arterial stiffness and reduced vessel integrity, meaning the vein is less elastic and more prone to rupture when a foreign object like a catheter is inserted.
Long-term use of certain medications, particularly systemic corticosteroids, can also severely affect vein structure. Steroids can weaken the supportive connective tissue and capillary walls around the vein, leading to a condition known as vascular fragility. Furthermore, some medications, such as high-concentration dextrose solutions, have a high osmolarity that chemically irritates the vein lining, causing inflammation that can widen the gaps between endothelial cells, allowing fluid to escape.
Extremes of age also contribute to vein vulnerability; pediatric patients often have veins that are small and highly mobile, making successful stabilization difficult. Similarly, geriatric patients frequently have veins that are naturally more fragile, less elastic, and have reduced subcutaneous fat for cushioning and support. Repeated IV access attempts in the same limb can also lead to scar tissue formation and sclerosis, resulting in a vein that is stiff and brittle, significantly increasing the likelihood of infiltration.
Recognizing Infiltration and Immediate Steps
The most common indicators of infiltration include swelling or puffiness at or just above the insertion site, caused by the accumulation of leaked fluid. The skin around the affected area may also feel noticeably cool to the touch due to the presence of IV fluid beneath the surface. Patients may report a feeling of pain, burning, or tightness around the site. The infusion rate on the pump may slow down or stop completely as the fluid meets resistance in the tissue.
If these signs are noted, the patient or caregiver must immediately notify medical staff and stop the infusion flow. The staff will then remove the catheter to prevent further leakage. After the device is removed, the affected limb is typically elevated above the level of the heart to help reduce swelling and encourage fluid reabsorption. Depending on the type of fluid that leaked, a warm or cold compress may be applied to the area; a warm compress is generally used for non-irritating fluids, while a cold compress may be used for irritating or hyperosmolar solutions to help contain the damage and reduce inflammation.