In summary, CPB provides a complex set of physiological circumstances during which the patient is subjected to severe physiological alterations with surprisingly few adverse sequelae. Our ultimate goal in performing medical research is to provide scientific insights that improve patient care. Results of studies of animal models may not always be applicable to man. Although CPB possesses faults inherent to any experimental model, it nonetheless provides a unique opportunity to study safely and effectively a variety of physiological and pharmacological variables that affect cardiovascular functions in man.