chapter  20
14 Pages

CO2 Inferior Vena Cavography

WithKyung J. Cho

CO2 is a safe contrast agent for inferior vena cavography if the current CO2 delivery

methods (the hand-held syringe and the plastic bag system) are used correctly. CO2 can

provide accurate measurement of vena caval diameter and anatomy necessary for filter

placement and caval interventions. Therefore, CO2 is the preferable contrast medium

because intravascular administration of the gas does not cause allergic reaction or renal

failure. In order to optimize the use of CO2, a thorough understanding of the physical prop-

erties of CO2 and proper techniques for its use are required. Without air contamination

during CO2 injection, vital signs should remain stable during and after CO2 injection in

quantities of up to 60 cc. Because of the low viscosity of CO2, the gas can be injected using

an end-hole catheter, eliminating the need for the use of a pigtail catheter used for contrast

vena cavography. CO2 should be used with caution in patients with severe pulmonary

hypertension because intracaval injection of the gas causes a transient increase in pulmonary

arterial pressure. The presence of intracardiac shunt is a relative contraindication to the use

of CO2 for vena cavography. When multiple injections are required, the injections should

be separated by two to three minutes to allow complete absorption of the gas injected.