A method for achieving tight glycemic control in a patient in need thereof is disclosed. The method comprises deploying an equilibrium glucose sensor within a blood vessel in the patient, coupling the sensor to a monitor that displays the blood glucose concentration, and administering a blood glucose regulator when the blood glucose concentration varies outside of the predetermined concentration range. The blood glucose regulator is administered in an amount sufficient to return the blood glucose concentration to within the predetermined concentration range, thereby achieving tight glycemic control.