iv fluid will leak into surrounding tissues when the tissues are compressed or there is restriction of the blood flow. when ivs are on pumps that have enough pressure to push fluid past venous restriction a infiltration can result.
these two terms, infiltration and extravasation, are often used interchangeably, but there really is a difference. (page 260-1, intravenous therapy: clinical principles and practice, by judy terry, leslie baranowski, rose anne lonsway and carolyn hedrick, published by the intravenous nurses society
". . .an infiltration is an inadvertent administration of a nonvesicant into the surrounding tissue. [infiltration most often occurs as a result of dislodging of the iv cannula.] extravasation is defined as an inadvertent delivery of a vesicant into the tissues. vesicants cause blistering, severe tissue damage, and even necrosis if extravasated.
[pathophysiology] when fluid leaks into tissue, the tissue is compressed because of restriction of blood flow, which decreases the amount of oxygen to the site and thus lowers the cellular ph. there is a loss of capillary wall integrity, increase in edema and, depending on severity, eventual cell death.
[more pathophysiology on extravasation] an oversimplification of the chemistry of an extravasation divides [vesicant] drugs into two categories, those that bind to dna and those that do not. the drugs that do not bind to dna cause immediate damage but are quickly metabolized or inactivated. this type of injury is similar to a burn in which the damage is immediate, followed by repair using the normal healing process.
the second class of drugs are those that bind to dna and not only cause immediate damage but lodge in the tissue, producing a prolonged effect. because of this binding effect, the cells lose their ability to heal spontaneously. . .drugs that bind to dna include alkylating agent nitrogen mustard. . .[some] antibiotics"
"it is essential that an extravasation be noted early before extensive fluid is allowed to infiltrate the interstitial tissues. a complete assessment of the patient, the intravenous site, the involved extremity, and the infusion system should be performed at regular intervals. the flow rate should never be increased to determine the infiltration of a vesicant, nor should a blood return be used as a reliable method to determine an infiltration. fluid can seep into the tissues from a previous puncture site or the vein insertion site, and increase the potential for tissue necrosis.
initial indications that tissue sloughing may occur include pain or burning at the site with progression to erythema and edema. tissue sloughing is usually apparent within 1 to 4 weeks because of tissue necrosis. necrosis can involve a small area or large area, including underlying connective tissues, muscles, tendons and bone, necessitating surgical intervention.
the severity of damage is directly related to the type, concentration, and volume of fluid infiltrated into the interstitial tissues. the most harmful of the vesicant medications are the antineoplastic agents, with doxorubicin (adriamycin) causing the most severe tissue necrosis. other medications that act as vesicants and cause tissue necrosis include dopamine hydrochloride, norepinephrine, potassium chloride in high doses, amphotericin, calcium and sodium bicarbonate in high concentrations.
when an extravasation is suspected, the infusate is discontinued immediately. treatment protocols established in written policies and procedures are initiated, and a new site is established, preferably in the opposite extremity or in a site above and away from the extravasated site.
institutional policies vary as to the treatment of the tissues in which an extravasation has occurred. usually, the cannula is left in place until after any residual medication and blood are aspirated, and an antidote particular to the vesicant is instilled into the tissues. after the cannula is removed, a dry, sterile dressing is applied to the site. and either cold or warm compresses are applied. cold compresses are usually used for the alkalating and antibiotic vesicants, whereas warm compresses are applied to an extravasation of the vinca alkaloids. the extremity is elevated and observed regularly for erythema, induration, and necrosis. the physician is notified, and tissue damage is evaluated by the physician for the possibility of surgical intervention."