Tag Archives: angiography

IV Contrast

We use CT scanning in trauma care so much that we tend to take it (and its safety) for granted. I’ve written quite a bit about thoughtful use of radiographic studies to achieve a reasonable patient exposure to xrays. But another thing to think about is the use of IV contrast.

IV contrast is a hyperosmolar solution that contains some substance (usually an iodine compound) that is radiopaque to some degree. It has been shown to have a significant impact on short-term kidney function and in some cases can cause renal failure.

Here are some facts you need to know:

  • Contrast nephrotoxicity is defined as a 25% increase in serum creatinine, usually within the first 3 days after administration
  • There is usually normal urine output and minimal to no proteinuria
  • In most cases, renal function returns to normal after 3-4 days
  • Nephrotoxicity almost never occurs in people with normal baseline kidney function
  • Large or repeated doses given within 72 hours greatly increase risk for toxicity
  • Old age and pre-existing diabetic renal impairment also greatly increase risk

If you must give contrast to a patient who is at risk, make sure they are volume expanded (tough in trauma patients), or consider giving acetylcysteine or using isosmolar contrast (controversial, may still cause toxicity).

Bottom line: If you are considering contrast CT, try to get a history to see if the patient is at risk for nephrotoxicity. Also consider all of the studies that will be needed and try to consolidate your contrast dosing. For example, you can get CT chest/abdomen/pelvis and CT angio of the neck with one contrast bolus. Consider low dose contrast injection if the patient needs formal angiographic studies in the IR suite. Always think about the global needs of your patient and plan accordingly (and safely).

Related posts:

Reference: Contrast media and the kidney. British J Radiol 76:513-518, 2003.

Contrast Blush in Children

A contrast blush is occasionally seen on abdominal CT in patients with solid organ injury. This represents active arterial extravasation from the injured organ. In most institutions, this is grounds for call interventional radiology to evaluate and possibly embolize the problem. The image below shows a typical blush.

Splenic contrast blush

This thinking is fairly routine and supported by the literature in adults. However, it cannot be generalized to children!

Children have more elastic tissue in their spleen and tend to do better with nonoperative management than adults. The same holds true for contrast blushes. The vast majority of children will stop bleeding on their own, despite the appearance of a large blush. In fact, if children are taken to angiography, it is commonplace for no extravasation to be seen!

Angiography introduces the risk of local complications in the femoral artery as well as more proximal ones. That, coupled with the fact that embolization is rarely needed, should keep any prudent trauma surgeon from ordering the test. A recently released paper confirms these findings.

The only difficult questions is “when is a child no longer a child?” Is there an age cutoff at which the spleen starts acting like an adult and keeps on bleeding? Unfortunately, we don’t know. I recommend that you use the “eyeball test”, and reserve angiography for kids with contrast extravasation who look like adults (size and body habitus).

Reference: What is the significance of contrast “blush” in pediatric blunt splenic trauma? Davies et al. J Pediatric Surg 2010 May; 45(5):916-20.