A significant number of cardiac surgical patients are at risk of inadequate perioperative oxygen delivery.The imbalance between oxygen delivery and consumption is initiator of series of events leading to MODS in turn leading to prolonged ICU/hospital stay, translating into increased health care cost and resources utilisation.Conventionally normalization of vitals is utilized as end point of resuscitation ,which may not be true reflection of perfusion at tissue level due to compensatory mechanisms. Ideal marker should be able to assess resolution of hypoperfusion.central venous oxygen saturation and lactate have been utilized in various clinical situations to assess adequacy of perfusion such as shock and sepsis. Combining these two markers can be utilized as a tool to assess incidence of occult hypoperfusion and adequacy of resuscitation.