What is the optimal device for carbon dioxide deairing of the cardiothoracic wound and how should it be positioned?

OBJECTIVES: To compare recently described insufflation devices for efficient carbon dioxide (CO(2)) deairing of the cardiothoracic wound and to determine the importance of their position.
DESIGN: Experimental and clinical.
SETTING: A cardiothoracic operating room at a university hospital. PARTICIPANTS: A full-size torso with a cardiothoracic wound and 10 patients undergoing cardiac surgery.
INTERVENTIONS: Insufflation of CO(2) into the wound cavity at 2.5, 5, 7.5, and 10 L/min with a multiperforated catheter and a 2.5-mm tube with either a gauze sponge or a gas-diffuser of polyurethane foam at its end. The devices were tested when positioned at the level of the wound opening and 5 cm below and after exposure to fluid.
MEASUREMENTS AND MAIN RESULTS: Deairing was assessed by measuring the remaining air content at the right atrium. With the multiperforated catheter, the gauze sponge, and the gas-diffuser, the lowest median air content in the torso was 8.4%, 2.5%, and 0.3%, respectively (p < 0.001), when positioned inside the wound cavity. When exposed to fluid, the gauze sponge and the multiperforated catheter immediately became inefficient (70% and 96% air, respectively), whereas the gas-diffuser remained efficient (0.4% air). During surgery, the gas-diffuser provided a median air content of 1.0% at 5 L/min, and 0.7% at 10 L/min.
CONCLUSIONS: For efficient deairing, CO(2) has to be delivered from within the wound cavity. The gas-diffuser was the most efficient device. In contrast to a gas-diffuser, a multiperforated catheter or a gauze sponge is unsuitable for CO(2) deairing because they will stop functioning when they get wet in the wound.