Acute kidney injury after cardiac arrest: a systematic review and meta-analysis of clinical studies

INTRODUCTION: The prevalence of and the risk factors for acute kidney injury (AKI) after cardiac arrest (CA), and the association of AKI with outcome have not been systematically investigated so far. EVIDENCE ACQUISITION: In this systematic review and meta-analysis, studies on adult patients (dating from January 1966 to August 2015) published as full-text articles were screened. Two authors independently extracted data and assessed study quality using the Quality Assessment Tool of the U.S. National Institute of Health. Data were summarized using weighted means. EVIDENCE SYNTHESIS: Eight studies (total 1693 patients; 68% males) were included. The incidence of AKI was 37%. In six studies where a standard AKI definition (RIFLE, AKIN or KDIGO) was used, the incidence for AKI stage 1 or higher was 52%. AKI occurred at a median of 1-2 days from cardiac arrest in 6/8 studies. Renal replacement therapy (RRT) was used in 239 AKI patients (33%), of whom five (2%) still needed RRT at 30 days after CA. An initial non-shockable rhythm, a longer duration of arrest, higher creatinine levels on admission, and the presence of shock or higher blood lactate after resuscitation were significant predictors of AKI occurrence. Hospital mortality was significantly higher in AKI vs. non-AKI patients (OR 2.63 [1.86-3.68]; P<0.0001). CONCLUSIONS: post-arrest AKI has an early onset, occurs in more than 50% of CA patients, and it is associated with increased mortality. Decreased renal function on admission, an initial non-shockable rhythm and both pre-arrest and post-arrest markers of hypoperfusion are associated with increased risk of AKI in this setting.