Exposure to radiocontrast may cause AKI. However, the association is controversial because population studies do not replicate risk. Evidence regarding the prevention of contrast-induced AKI is weak, and often conflicting.
Administration of normal saline at a dose of 1 mL/kg/hour for several hours before and after the contrast is believed to be beneficial in the prevention of contrast nephropathy. The American College of Radiology and the National Kidney Foundation recommend prophylaxis with normal saline for patients receiving iodinated contrast and AKI or estimated GFR less than 30 mL/minute/1.73 m². The UK National Institute for Health and Care Excellence (NICE) recommends use of intravenous volume expansion only for inpatients considered at particularly high risk: for example, if they have preexisting renal impairment.[Evidence C] However, a large study did not show benefit from preventative intravenous hydration in patients at risk of contrast-induced nephropathy according to current guidelines.
Sodium bicarbonate is unlikely to be superior to saline for the prevention of contrast-induced injury. Studies assessing the efficacy of acetylcysteine administration before contrast exposure have produced conflicting results, but larger trials show no significant benefit.
Treatment during cardiac surgery
Sodium nitroprusside has been shown to be associated with improved renal function when given during the rewarming period of nonpulsatile coronary pulmonary bypass in the course of coronary artery bypass grafting surgery.
One large meta-analysis of 4605 adult patients undergoing cardiac surgery with cardiopulmonary bypass and receiving different forms of therapy, concluded that fenoldopam, atrial natriuretic peptide, and brain natriuretic peptide showed evidence of nephroprotection, although none reduced all-cause mortality. These interventions remain hard to justify based on overall evidence.
One study analyzing the effect of high-dose perioperative atorvastatin in patients undergoing elective coronary artery bypass grafting, valvular heart surgery, or ascending aortic surgery suggested no benefit. In a similar patient population, AKI was more common among those randomized to perioperative rosuvastatin than to placebo.
Results from one meta-analysis suggest that preoperative intra-aortic balloon pump support for high-risk patients undergoing coronary artery bypass grafting surgery lessens the risk of postoperative AKI.
Compared with on-pump coronary artery bypass grafting, off-pump surgery appears to reduce the risk of postoperative AKI.
One meta-analysis of 1308 adult patients undergoing cardiac surgery concluded that perioperative administration of dexmedetomidine reduced the risk of AKI; however, there was no significant reduction in in-hospital mortality.
Critically ill patients in intensive care unit setting
Severe metabolic acidosis
One trial reported improved outcome and reduced mortality among a subset of critically ill patients with AKI who received sodium bicarbonate infusion for correction of metabolic acidemia. However, sodium bicarbonate was not associated with clinical benefit in unselected critically ill patients with severe acidemia.
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