Contrast Induced Nephropathy – sense at last. St Emlyn’s

Just a quick post to brighten your weekend. Like many of you I have lost count of the number of times I’ve been challenged about performing a contrast CT for a critically ill/injured patient because we don’t yet know the creatinine level. Despite the evidence for contrast induced nephropathy being dubious, and large observational trials indicating that it is not a factor in subsequent renal failure the challenge has persisted.

Interestingly the challenge has usually been about the absence of a result, with a request to delay the scan until it it is known. In contrast (sic) a patient with known renal impairment and/or high creatinine was a short and satisfying conversation as we already knew what the issue was. Paradoxically, when there is uncertainty, this often led to delay. If we know what the renal function is, even if awful then there is NO delay as a ‘decision’ CAN be made. When we are waiting for a result to come back clinicians feel that there is not enough information to make a decision and so they wait. When you step back and think about it this makes almost no sense at all, but it’s the nature of humans who can comfortably handle an abnormal result, but not uncertainty.

Thankfully, the Royal College of Emergency Medicine and the Royal College of Radiologists have now jointly agreed the following statement that puts the matter to rest in nearly all cases.

You can download and share (I won’t say with whom) the document here.

Whilst this is all good news, there are some caveats. The document states that a senior decision maker should be involved in the decision to perform a CT in an emergency situation (life/limb threatening), which is fair enough as an SDM should be involved in the care of all these patients.

The key matters though are that renal function, age, pre-existing renal, diabetic, or metformin are not reasons to delay. Similarly age should not be a barrier and there is no requirement to give pre-CT intravenous fluids (as they have no protective effect).

This is good news for our patients, and good news for our departments. It will hopefully reduce delays and a few difficult conversations, but please do read the document for yourself and make sure that you understand the agreement and the caveats.

Now that we’ve sorted CIN, what day to day referral problem would you like to see resolved next week? Send us your thoughts and wishes and we’ll see what we can do 🙂

vb

S

Further reading

1. Risk of Acute Kidney Injury After Intravenous Contrast Media Administration. https://pubmed.ncbi.nlm.nih.gov/28131489/
2. Aycock, Ryan D.; Westafer, Lauren M.; Boxen, Jennifer L.; Majlesi, Nima; Schoenfeld, Elizabeth M.; Bannuru, Raveendhara R. (August 2017). “Acute Kidney Injury After Computed Tomography: A Meta-analysis”. Annals of Emergency Medicine. 71 (1): 44–53.e4. doi:10.1016/j.annemergmed.2017.06.041. PMID 28811122. S2CID 27167779.
3. Simon Carley, “Top 10 trauma papers 2017-2018 for @traumacareUK conference. St Emlyn’s,” in St.Emlyn’s, April 18, 2018, https://www.stemlynsblog.org/top-10-trauma-papers-2017-2018-for-traumacareuk-conference-st-emlyns/.
4.  McDonald, Robert; McDonald, Jennifer S.; Carter, Rickey E.; Hartman, Robert P.; Katzberg, Richard W.; Kallmes, David F.; Williamson, Eric E. (December 2014). “Intravenous Contrast Material Exposure Is Not an Independent Risk Factor for Dialysis or Mortality”. Radiology. 273 (3): 714–725.