subject is scheduled for cardiac surgery involving bypass circuit

subject is older than 18 years

subject is willing to participate and he/she has signed a consent form

subject is unable to provide written informed consent

subject is incarcerated at the time of the study

subject is affected by any condition that, in the opinion of the surgical team, may pose additional risks

patients with renal disease (defined as serum creatinine greater than 1.5 mg/dl)

patients with history of active liver disease

patients on emergency cases

patients on heparin anticoagulation before the beginning of the study