The aim of this study was to investigate the changes of cerebral oxygen saturation (rSO2) during anesthesia induction.

The aim of this study was to investigate the relationship between the cerebral oxygen saturation (rSO2) and pressure of carbon dioxide (PaCO2) and oxygen (PaO2) in arterial blood and to identify the covariates between rSO2 and PaCO2 and PaO2 during the period of anesthesia induction.

Inclusion Criteria:

• Patients were included in the study if they were ethnic Chinese, between 18 and 65 years old, American Society of Anesthesiologists (ASA) physical status I or II, and undergoing a radical operation for mastocarcinoma.

Exclusion Criteria:

• Patients were excluded if they had a body mass index exceeding 30 kg/m2, had a history of hypertension or diabetes mellitus, or were allergic to anesthesia drugs used in the study.

Female patients scheduled for elective radical operations for mastocarcinomaat in the First Hospital of China Medical University will be recruited for the study