Background: Acute renal failure is a common complication in critically ill patients and carries an increased morbidity and mortality. N-acetylcysteine is an antioxidant and anti-inflammatory agent that may counteract some of the pathophysiologic derangements in shock states.
Objective: To test whether the administration of N-acetylcysteine, compared with placebo, reduces the incidence of acute renal failure in hypotensive patients.
Design: Prospective, randomized, double-blinded, placebo-controlled study.
Setting: Intensive care units of a university tertiary care hospital.
Patients: One hundred forty-two patients with new onset (within 12 hrs) of at least>or=30 consecutive minutes of hypotension and/or vasopressor requirement.
Interventions: Patients were randomized to receive either N-acetylcysteine or placebo for 7 days, in addition to standard supportive therapy.
Measurements and main results: Patients who received N-acetylcysteine had an incidence of acute renal failure (>or=0.5 mg/dL increase in creatinine) of 15.5%, compared with 16.9% in those receiving placebo (p=.82, not significant). There were no significant differences between treatment arms in any of the secondary outcomes examined, including incidence of a 50% increase in creatinine, maximal rise in creatinine, recovery of renal function, length of intensive care unit and hospital stay, requirement for renal replacement therapy, and mortality. Among patients receiving N-acetylcysteine, there were trends toward reduced incidence of acute renal failure in patients with baseline Sequential Organ Failure Assessment (SOFA) score>8 (p=.12), lower SOFA scores during the first 4 days of treatment (p=.28), and reduced mortality in patients<65 yrs of age (p=.20).
Conclusions: There were no significant differences in any of our primary or secondary end points between patients treated with N-acetylcysteine or placebo. Trends toward reduced incidence of acute renal failure in patients with baseline SOFA score >8, reduced SOFA scores during the first 4 days, and reduced mortality in patients<65 yrs of age are provocative but require further study to determine their clinical significance.