To investigate the relationship of tissue oxygenation of different organs and tissue beds (e.g., a tissue bed on the arm vs. leg vs. flank tissue bed(s) and renal tissue bed, and thus can be used as a surrogate of renal tissue oxygenation monitoring.

In this study, we will monitor tissue oxygenation of four different tissue beds including cerebral tissue (SctO2) on the forehead, and 3 somatic tissue beds monitored on the forearm (SarmO2), upper leg (SlegO2), and the renal region (SrrO2). The primary end point is AKI and the secondary end points are postoperative major non-renal complications (e.g. stroke, delirium, myocardial infraction, heart failure, new or worsening arrhythmia, mechanical ventilation > 24 hours, deep wound infection, etc.) and mortality. The associations between tissue oxygenation of different tissue beds, i.e. SctO2, SarmO2, SlegO2, and SrrO2, and AKI and non-renal outcomes will be compared to explore the tissue bed(s) whose oxygen saturation has a stronger association with the outcomes of interest. The strength of this study is to use the patient as self-control.

Inclusion Criteria:

• Written informed consent obtained
• Age ≥18 years of age
• Double valves replacement surgery with cardiopulmonary bypass (CPB)

Exclusion Criteria:

• The Trauma, deformity or abnormality sites which the sensor will be put may affect the monitoring of the data
• Preoperative renal dysfunction needs renal replacement therapy
• Emergency surgery
• Preoperative intubated patient
• Unable to cooperate with the study, i.e., mental illness, et al
• Patients with hemoglobin and anemia
• Participate in other trials in the prior 3 months
• Patient refuses to participate in the study
• Patient is unfit for the study decided by reach stuff

Patients who are going to have double valves replacement surgery