Perioperative acute kidney injury (AKI) is not uncommon and is associated with considerable morbidity and mortality. Recently, several definition systems for AKI were proposed, incorporating both small changes of serum creatinine and urinary output reduction as diagnostic criteria. Novel biomarkers are under investigation as fast and accurate predictors of AKI. Several special considerations regarding the risk of AKI are of note in the surgical patient. Co-morbidities are important risk factors for AKI. The surgery in itself, especially emergency and major surgery in the critically ill, is associated with a high incidence of AKI. Certain types of surgeries, such as cardiac and transplantation surgeries, require special attention because they carry higher risk of AKI. Nephrotoxic drugs, contrast dye, and diuretics are commonly used in the perioperative period and are responsible for a significant amount of in-hospital AKI. Before surgery, the anaesthetist is required to identify patients at risk of AKI, optimize anaemia, and treat hypovolaemia. During surgery, normovolaemia is of utmost importance. Additionally, the surgical and anaesthesia team is advised to use measures to reduce blood loss and avoid unnecessary blood transfusion. Hypotension should be avoided because even short periods of mean arterial pressure <55-60 mm Hg carry a risk of postoperative AKI. Higher blood pressures are probably required for hypertensive patients. Urine output can be reduced significantly during surgery and is unrelated to perioperative renal function. Thus, fluids should not be given in excess for the sole purpose of avoiding or treating oliguria. Use of hydroxyethyl starch needs to be reconsidered. Recent evidence indicates a beneficial effect of administering low-chloride solutions.
KEYWORDS: acute kidney injury; perioperative complications; perioperative management; surgery
PLoS One. 2015 Dec 15;10(12):e0145042. doi: 10.1371/journal.pone.0145042. eCollection 2015.
BACKGROUND: New renal biomarkers measured in urine promise to increase specificity for risk stratification and early diagnosis of acute kidney injury (AKI) but concomitantly may be altered by urine concentration effects and chronic renal insufficiency. This study therefore directly compared the performance of AKI biomarkers in urine and plasma.METHODS:This single-center, prospective cohort study included 110 unselected adults undergoing cardiac surgery with cardiopulmonary bypass between 2009 and 2010. Plasma and/or urine concentrations of creatinine, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), liver fatty acid-binding protein (L-FABP), kidney injury molecule 1 (KIM1), and albumin as well as 15 additional biomarkers in plasma and urine were measured during the perioperative period. The primary outcome was AKI defined by AKIN serum creatinine criteria within 72 hours after surgery.RESULTS:Biomarkers in plasma showed markedly better discriminative performance for preoperative risk stratification and early postoperative (within 24h after surgery) detection of AKI than urine biomarkers. Discriminative power of urine biomarkers improved when concentrations were normalized to urinary creatinine, but urine biomarkers had still lower AUC values than plasma biomarkers. Best diagnostic performance 4h after surgery had plasma NGAL (AUC 0.83), cystatin C (0.76), MIG (0.74), and L-FAPB (0.73). Combinations of multiple biomarkers did not improve their diagnostic power. Preoperative clinical scoring systems (EuroSCORE and Cleveland Clinic Foundation Score) predicted the risk for AKI (AUC 0.76 and 0.71) and were not inferior to biomarkers. Preexisting chronic kidney disease limited the diagnostic performance of both plasma and urine biomarkers.CONCLUSIONS:In our cohort plasma biomarkers had higher discriminative power for risk stratification and early diagnosis of AKI than urine biomarkers. For preoperative risk stratification of AKI clinical models showed similar discriminative performance to biomarkers. The discriminative performance of both plasma and urine biomarkers was reduced by preexisting chronic kidney disease.
Conclusions. Wide acute perioperative glycemic fluctuations should be avoided as they are associated with a significantly increased risk of AKI and ICU length of stay in both the diabetics and the nondiabetics.