ITBV: Intrathoracic Blood Volume
Relationship of Global End-diastolic Volume (GEDV) and Intra-Thoracic Blood Volume (ITBV)
Experimentally, it has been shown that the total amount of blood in the cardiopulmonary circulation is related to the GEDV, and is usually 1.25 times the total volume of the blood in the ventricles.
The ITBV calculation does not take into account any ort of hideous structural abnormalities in the heart, like shunts, space occupying lesions, or massive pulmonary emboli.
ITBV will be inaccurate in patients with a saddle embolus or pulmonectomy.