I V infiltration: Not just a peripheral problem

Nursing, Sep 1999 by Hadaway, Lynn C

PETE TUCKER, 55, spent 3 days in the intensive care unit following a colon resection for cancer. He was transferred to your unit this morning with a nontunneled triple-lumen catheter inserted in the left subclavian area. Examining the catheter and dressing, you notice an excessive amount of moisture under the transparent dressing. Mr. Tucker tells you he feels some burning in the area around the catheter insertion site. The fluid infusing (at 83 ml/hour) is 5% dextrose in 0.45% sodium chloride with 40 mEq potassium chloride added to the liter.

You may be all too familiar with the clinical signs and symptoms of infiltration at a peripheral catheter insertion site: swelling or leaking at the site, pain, and skin coolness and blanching. But what about a central catheter insertion site? Can infiltration be a problem?

Unfortunately, yes. Also known as extravasation, infiltration isn't just a peripheral problem. It can occur with any type of vascular access device (VAD), including nontunneled and tunneled central venous catheters, implanted ports, and even intraosseous and epidural infusion devices.

Although the terms infiltration and extravasation are often used interchangeably, the Intravenous Therapy Standards of Practice published by the Intravenous Nurses Society defines infiltration as the inadvertent administration of a nonvesicant solution into surrounding tissue; extravasation is the inadvertent administration of a vesicant solution into surrounding tissue. Vesicants are solutions capable of causing tissue injury or destruction if they escape into surrounding tissue. Examples include chemotherapy agents, certain electrolyte solutions, radiographic contrast media, and vasopressors (see Recognizing Vesicant Medications).

In this article, I'll discuss how to recognize and treat infiltration or extravasation at various peripheral and central intravenous (I.V.) sites. To thoroughly examine the clinical picture, let's first examine the mechanisms that cause fluid to escape from the catheter and the processes that cause injury to the subcutaneous tissue.

Precipitating events

Factors leading to infiltration include mechanical forces that displace the VAD, obstructions to blood flow around or through the catheter, and the inflammatory process. Once subcutaneous tissue is exposed to the escaping fluid, damage is caused by osmotic and pH differences, ischemia, compression, and direct toxicity.

Complications of infiltration fall into three categories:

ulceration and possible tissue necrosis. The severity of tissue damage depends on many variables, including the drug's vesicant potential, the amount of drug extravasated, and the venipuncture site. Contrary to popular assumptions, ulceration isn't immediately apparent. The patient may initially complain of burning at the site, as Mr. Tucker did, or may state that the infusion "feels different now." The ulcer may actually take days or weeks to develop. Treatment for ulceration may include debridement, skin grafting, or other surgical reconstruction.

compartment syndrome. Compartments are areas of the body where muscles, nerves, and vessels are confined in relatively inflexible spaces bounded by skin, fascia, and bone. When fluid inside a compartment increases, the venous end of the capillary bed becomes compressed. If vessels can't carry away the excessive fluid, hydrostatic pressure rises, leading to compartment syndrome: arteriolar compression, vascular spasm, pain, and muscle necrosis inside the compartment. Functional muscular changes can occur within 4 to 12 hours of injury. Within 24 hours ischemic nerve damage can result in functional loss of the extremity. The extremities contain many compartments, increasing the possibility of compartment syndrome from infiltration at a peripheral site.

reflex sympathetic dystrophy syndrome. Although the exact pathogenesis is unknown, this chronic pain syndrome is caused by trauma to nerve complexes or soft tissue. When a severe infiltration occurs, a chronic and exaggerated inflammatory process begins, leaving the patient with limited function in the affected extremity.

Not always obvious

Classic signs and symptoms of infiltration include edema and changes in the site's appearance and temperature, such as swelling, blanching, and coolness. The patient may complain of pain or discomfort and a feeling of tightness around the site.

But not all patients experience discomfort. In fact, clinical research demonstrates that pain, edema, and induration are unreliable indicators of infiltration, which isn't always easy to spot.

The greatest discomfort and best-- defined borders of infiltrated fluid tend to occur immediately. Depending on the fluid type, infiltrated fluid may then dissipate, relieving signs and symptoms.

The type and amount of fluid that infiltrates dictates the total amount of fluid in the infiltrated area. A hypertonic fluid draws fluid out of cells, increasing the amount of fluid in tissue. A hypotonic fluid will quickly be absorbed by surrounding cells; however, depending on the volume of infiltrated fluid, the cells may swell and rupture, spilling fluid back into the tissue.