Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders>>>>>Acute Renal Failure
Question 2#

A 35-year-old obese female with a past medical history of type 2 diabetes, chronic kidney disease (CKD) stage 3, chronic obstructive pulmonary disease (COPD), and deep vein thrombosis (DVT) is brought to the emergency room with acute-onset shortness of breath. She is on home oxygen for the COPD, warfarin, and subcutaneous insulin therapy. Her chest x-ray reveals hyperinflated lung fields, and CT angiogram did NOT reveal pulmonary embolism (PE). She was admitted and treated for COPD exacerbation. Serum creatinine is noticed to have increased to 2.6/dL from a baseline of 1.3 mg/dL with concern for contrast-induced acute kidney injury (CIAKI).

Which of the following strategies is MOST likely to prevent CI-AKI? 

A. Use of isotonic saline infusion before and after CT angiogram
B. Use of a lower-osmolality, lower-viscosity contrast agent
C. Use of V/Q scan to rule out PE
D. Use of N-acetyl cysteine (NAC) before and after the angiogram

Correct Answer is C


Correct Answer: C

CI-AKI is the most common iatrogenic cause of AKI. The incidence is reported to be as high as 20% to 30% in patients with preexisting renal dysfunction. The most effective method of preventing CI-AKI is avoidance of iodinated contrast unless absolutely indicated, especially in patients with compromised kidney function.

Reduction in renal blood flow, tubular cell damage, and tubular obstruction are implicated in the pathogenesis of CI-AKI. Therefore, volume expansion with normal saline has been used extensively with the goal of improving medullary blood flow, diluting the contrast agent in the tubule, and increasing urinary flow. Low-osmolality contrast agents are less toxic to the kidneys as compared to high-osmolality agents. 

Although NAC has antioxidant and anti-inflammatory properties and proposed to have a beneficial role in the prevention of CI-AKI, the largest trial on this subject did not confirm this. The most effective method of preventing CI-AKI is avoiding studies requiring IV contrast administration.


  1. Akbari A, Hiremath S. Contrast-induced acute kidney injury. In: Vincent JL, Abraham E, Moore FA, Kochanek PM, Fink MP, eds. Chapter 111: Textbook of Critical Care. 7th ed. 790-793.
  2. ACT investigators. Acetyl cysteine for prevention of renal outcomes in patients undergoing coronary and peripheral vascular angiography: main results from randomized acetyl cysteine for contrast-induced nephropathy trial (ACT). Circulation. 2011;124(11):1250-1259.