Patients with cardiovascular disease (acquired or congenital; cyanotic or acyanotic; unrepaired, palliated or fully repaired) requiring cardiac catheterization to diagnose or treat the disease will be eligible for study.

Inclusion Criteria:

• The subject is male or female;
• The subject is of any racial or ethnic group;
• The subject is between 0 days and 12 years of age;
• Is less than 40 kg;
• The subject is scheduled for a cardiac catheterization for treatment or diagnosis of a cardiovascular disease;
• The scheduled cardiac catheterization includes catheter placements in the central venous circulation and central arterial circulation, or catheter placement in the central venous circulation with a pre-existing arterial catheter;
• The subject is American Society Anesthesiologist (ASA) status 1 through 4; and
• The subject's legally authorized representative has given written informed consent to participate in the study and, when appropriate, the subject has given assent to participate.

Exclusion Criteria:

• Is greater than twelve (12) years of age;
• Has pre-existing allergies to adhesive tapes or adhesives on neonatal ECG pads;
• Has pre-existing skin condition at the site where the Nonin cerebral oximeter sensor will be placed (e.g., eczema, dermatitis);
• Has craniofacial disease preventing application of the sensor to the forehead;
• Has sickle cell anemia or other hemoglobinopathy;
• Has disease of the cerebrovasculature including the jugular or carotid vessels;
• Was previously on ECMO involving the carotid or jugular vessels that could have resulted in disease or ligation;
• Is not able to be in a supine position with cardiac catheterization laboratory table angle zero degrees with a neutral neck position at zero degrees rotation;
• Has acute neurological injury (seizure, stroke, encephalopathy, meningoencephalitis currently or within the past 10 days), or a structural brain lesion (eg, arteriovenous malformation, cyst) in the optical field beneath the sensor;
• Has an emergency, life-threatening condition (American Society of Anesthesiologists Physical status 5 or 6) impacting the ability to obtain informed consent;
• Or has another condition, which in the opinion of the principal investigator would not be suitable for participation in the study.