Carbon dioxide embolism induced right coronary artery ischaemia during off-pump obtuse marginalis artery grafting

Abstract

Although use of carbon dioxide (CO2) blower has been regarded safe during off-pump coronary bypass surgery (OPCAB), we experienced a case of right coronary artery ischaemia induced by retrograde CO2 embolism originating from the opened obtuse marginalis artery during OPCAB. The spray pressure can exceed the diastolic pressure, especially during grafting at the lateral or posterior wall when haemodynamic compromise due to mechanical heart displacement is most severe. In this situation, CO2 blowing at an incompletely slinged coronary arteriotomy site can result in retrograde migration of CO2 into the ascending aorta causing coronary embolism of the right coronary artery. When signs of ischaemia on the right coronary artery are encountered during grafting of other coronary artery, although CO2 blower has been used, gas embolism should also be considered as the cause and identified at the mid-oesophageal aortic valve long-axis view. When confirmed, the use of gas blower should immediately be discontinued and coronary perfusion pressure increased while allowing time for the CO2 to be absorbed. In case of massive embolism, needle aspiration of the gas should also be considered.