Intraoperative Renal Desaturation and Postoperative Acute Kidney Injury

Postoperative acute kidney injury (AKI) is a severe complication after liver resection and contributes to increased morbidity and mortality.

Advanced age reduces renal autoregulatory capacity due to physiological and functional changes, thus render the elderly to suffer postoperative AKI and probably the consequent chronic kidney disease. Thus, it is essential to identify those patients at high risk to develop postoperative AKI to optimize perioperative prevention and protection strategies.

Despite the multiple risk factors and potential mechanisms that have been identified, the diagnosis of postoperative AKI depending on serum creatinine changes have been delayed for early identification of postoperative AKI. It is of great interest to develop target strategies for close motoring of renal function.

This study is a prospective cohort study to investigate the associations between intraoperative renal desaturation measured by NIRS and postoperative AKI. The investigators intend to access the optimal threshold values of renal rSO2 for predicting postoperative AKI. Desaturation of renal rSO2 will be defined by the severity and duration of NIRS values during the surgical process. The principal clinical outcome of the study is postoperative AKI, defined as an absolute increase in serum creatinine of 0.3 mg/dL within 48 hours or a 1.5-fold increase from preoperative baseline within seven days after surgery, according to the Kidney Disease: Improving Global Outcomes (KDIGO) criterion.

Inclusion criteria

• Elderly patients (defined as 60 years of age or older) scheduled for elective liver resection

Exclusion criteria

• Emergency surgery
• Liver transplantation
• Preoperative hemodialysis
• BMI > 30
• Renal depth (distance from the capsule of the kidney to the skin surface) > 4 cm
• Unable or failed to sign the informed consent