Removal of intracardiac air during valvular surgery should be accomplished in the most effective manner. We conducted a prospective randomized controlled trial to compare mechanical de-airing and carbon dioxide (CO2) field flooding in 18 patients undergoing elective valvular surgery. Transoesophageal echocardiography was used to record intracardiac bubbles, and this was assessed postoperatively by two independent echocardiographers blinded to treatment group. Both assessors graded the bubble count higher in the mechanical deairing group compared with the CO2 flooding group, and there was good agreement between assessors. CO2 field flooding is more effective than mechanical de-airing in removing intracardiac bubbles following valvular surgery.