"It would not be considered a breach of standard of care to allow a small extravassated to occur. Most of the time, they can't be totally prevented. The incidence of minor extravessation is unknown, but Federle et al (Radiology 1998;206(3):637) concluded that the complication rate is higher if an automatic device injects the dye. When dye was injected with a mechanical bolus injection via a plastic catheter placed in an upper extremity, about one percent of patients experienced an extravessation. Curiously, the injection rate did not influence the extravessation rate. Although 16 patients had a volume of at least 50 mls of dye extravessate, none required surgical intervention and none had long-term effects. Other authors also have concluded that the rate of injection is not correlated with extravessation rates (Radiology 1998;209(2):411).  " http://www.em-news.com/pt/re/emmednews/fulltext.00132981-200406000-00024.htm;jsessionid=LwpGstvGJ3qsWFmqT1sTYygqpkCJnFxn0QDQSvTr2ym2nk0hJTJt!-2060166207!181195629!8091!-1

According to what I have read, interventions such as attempting to aspirate the dye through the iv line, injecting saline to dilute the material, or other more invasive procedures  such as infiltration of steroids are not necessary and only serve to increase the incidence of complication.  The dye is not tissue necrosive, and having it extravessate does not increase the already associated risks such as allergic reaction and kidney toxicity.  The main problems associated with extravisation have to do with the pressure of the automatic injector, not the dye itself.  Compartment syndrome is the rare but serious risk associated with a precipitous injection.  This is risk is increased with metal needles and/or using the dorsum of the hand as the injection site.

To end with another quote from an article (see above html link):

"Aggressive ED procedures are gratifying when successful, and emergency physicians like to intervene whenever they can. However, there is very little one need do - or can or should do - with the extravessation of nonionic contrast material. Non-intervention is usually the best policy. It's simply not much of an issue in the long run, although a large extravessation can produce a few anxious moments when a patient is rushed to the ED. Minor pain and phlebitis may occur a few days later, but we usually don't see such patients because they are handled by the radiology staff. The authors of this study suggest keeping the patient in the radiology suite, but there is little chance of that occurring in most hospitals these days if observation for more than a few minutes is required. Hopefully public relations begins with the technician and radiologist who do not overestimate the severity of the extravessation, unnecessarily upsetting the patient. Rushing a patient to the ED is a bad tactic, especially if he has to wait hours to see the emergency physician after the precipitous transfer."

So to put it all together, watchful non-intervention in a calm manner designed to reassure the patient is the best policy.  Ice therapy and elevation can be used but have not been shown to change the already low incidence of complication in this benign and fairly common (up to 1% of contrast studies) event.  Compartment syndrome having to do with the pressure of auto injectors is the problem on your hit-list.

I hope this helps in the evaluation of future policy or in your own practice at the bedside.

Sincerely,

Spencer