Primary study objective is to test the accuracy of the Genius 2 tympanic thermometer and the Exergen TAT-5000(TM) temporal artery thermometer as compared with serial perioperative core temperature measurements obtained in cardiac surgical patients during cardiopulmonary bypass. Study hypothesis: The Genius 2 thermometer will display greater precision and accuracy than the Exergen TAT-5000 thermometer when compared to core body temperature in patients undergoing CABG surgery.

Inclusion Criteria:

• Male or female adult subjects greater than/equal to 18 years of age providing signed informed consent
• Febrile or afebrile
• Planned monitoring of core temperature at a minimum of two separate sites, one of which includes the pulmonary artery
• Planned use of cardiopulmonary bypass for a cardiac surgical procedure.

Exclusion Criteria:

• Mist tents or oxygen hoods
• Hot or cold applications to the head
• Patients that have the planned use of deep hypothermic circulatory arrest
• Aural anomalies (e.g., external auditory canal less than 2cm in length, persistent ear pain)
• Any other major anomaly, surgery or medical condition precluding participation according to manufacturers' stated exclusions or in the opinion of the principal investigator
• Blood, cerumen, excessive hair, inflammation, infection, ulceration or foreign object in the ear observed by otoscopic examination
• Any other signs or symptoms of distress or a condition which would, or in the opinion of the principal investigator, render their participation in the study detrimental to their well-being.
• Previous refusal or enrollment in this study
• Previous or concurrent participation in a clinical trial of a drug or device within the past 30 days.

Adults greater than/equal to 18 years of age scheduled for a cardiac surgical procedure requiring cardiopulmonary bypass.