An observational study designed to evaluate the performance of a new Near Infrared Spectroscopy (NIRS) tissue oximeter device in the clinical setting, including a cerebral sensor and peripheral sensor. Fifty patients who are undergoing open-heart surgery will be enrolled and tissue oximetry measurement will be collected throughout the surgical procedure and for up to 24 hours following surgery. Tissue oximeter measurement of the brain and skeletal tissue will be added to the standard intra-operative patient monitoring. Measures of delirium will be collected using a standardized questionnaire. The relationship between cerebral oximetry measures and delirium scores will be explored.

See Eligibility Criteria section

Inclusion Criteria:

• Age 18 years or older
• Weigh at least 40 kg
• Undergoing Coronary Artery Bypass Graft (CABG) and/or valvular surgery requiring the use of Cardio Pulmonary Bypass (CPB) or Left Ventricular Assist Device (LVAD), inclusive of any concomitant procedure
• Willing and able to provide informed consent
• Able to communicate and read in English

Exclusion Criteria:

• Emergency procedure such that informed consent may not be obtained
• Known cognitive impairment, history of delirium or dementia
• Known hemodialysis or fistula graft
• Delirium Observation Score (DOS) Score of >6 prior to surgery
• Pre-existing skin condition at the site of sensor application (e.g. eczema, dermatitis)
• Any known contraindication or sensitivity to the cerebral oximeter sensor

Patients undergoing Coronary Artery Bypass Graft (CABG) and valvular surgery with cardiopulmonary bypass