Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Table 3 Contraindications for the use of carbon dioxide angiography

Contraindication	What the clinician should do
CO2 arteriography performed above the diaphragm may result in cerebral air embolism if the patient has a left-to-right cardiopulmonary shunt	Do not use CO2 arteriography in patients with cardiac septal defect, pulmonary arteriovenous malformation (AVM), or known left-to-right cardiopulmonary shunt. In cases of critical requirement for CO2 angiography, place the patient in the Trendelenburg position during imaging
CO2 can mix with nitrogen to reduce the solubility of CO2	Avoid the use of nitrous oxide sedation and anesthesia
CO2 should be avoided for use in the venous circulation of patients that have a right-to-left intracardiac shunt	Do not use CO2 venography in patients with a right-to-left intracardiac shunt, including tetralogy of Fallot. In cases of critical requirement for CO2 venography, place the patient in the left lateral decubitus position to allow CO2 to trap and dissolve in the right atrium
Delayed absorption of CO2 may occur in patients with chronic lung disease, such as chronic obstructive pulmonary disease (COPD), who have a high baseline CO2 level	Monitor and adjust the time interval between CO2 injections in patients with a high baseline CO2 level
CO2 increases pulmonary artery pressure and can exacerbate pulmonary hypertension	Check the pulmonary arteries for accumulation of CO2 gas dissipation within the initial 30-45 s following CO2 injection

CO₂: Carbon dioxide.