April 28, 2021

Background: It has long been thought that intravenous contrast can lead to acute kidney injury. Recent data, however, has called this dogmatic teaching into question.  Unfortunately, the data arguing against the association of contrast with AKI comes from observational trials and, thus, carry with it numerous biases.  One potential bias is baseline differences in the risk between exposure groups with patients not receiving contrast perceived to be at higher risk and those receiving contrast at lower risk of PC-AKI. Another example is selection bias due to requiring subsequent renal function testing in patients deemed to be higher risk and not those at lower risk.  Both of these can form a control group at high risk of kidney injury which creates a bias in favor of contrast and potentially masking harm.

April 9, 2020

Background: Most guidelines recommend prehydration prior to iodine-based contrast media to prevent postcontrast acute kidney injury (PC-AKI) in patients with CKD.  There is, however, a lack of evidence for the effectiveness of this as well as the potential adverse effects from the hydration itself (i.e. congestive heart failure exacerbation). We have covered the AMACING trial on REBEL EM which was a randomized clinical trial evaluating prehydration with 0.9% normal saline vs no prehydration in patients with estimated glomerlular filtration rates of 30 – 59mL/min/1.73m2.  In that study there was no difference in their primary outcome of contrast induced nephropathy (now called postcontrast acute kidney injury - PC-AKI) at 2 – 6 days after IV contrast (2.7% with prehydration vs 2.6% without prehydration). The trial we are are covering today, the Kompas trial, directly compared prehydration with sodium bicarbonate vs no prehydration prior to non-emergent intravenous contrast-enhanced CT in patients with CKD stage 3.

January 16, 2020

Background: Computed tomography pulmonary angiography (CTPA) is the current gold standard for diagnosing acute pulmonary embolism in the ED.  It has a high sensitivity, and specificity, is readily available, and can establish analternative diagnoses.  One issue with CTPA is that many hospital protocols create barriers for patients with chronic kidney disease or acute kidney injury (AKI) protocols in place from getting the necessary IV contrast.  There are several studies [2][3][4] that have evaluated the causal relationship between contrast exposure and nephrotoxicity. However, most of these studies are observational and retrospective in nature. The issue with retrospective studies is that they often cannot control for confounders and observational studies cannot give us causation, only association. We now have another retrospective observational study asking the same question, which has the inherent issues of previous studies.