Introduction: Carbon dioxide (CO2) insufflation into the cardiothoracic wound is used in cardiac surgery in order to improve de-airing of the heart and great vessels. The objective of this study was to compare the de-airing efficiency of various insufflation devices.
Method: De-airing was assessed by measuring the remaining air content (O2-analysis) at the right atrium in a full-size torso with a cardiothoracic wound cavity and in 10 patients undergoing cardiac surgery. CO2 was insufflated into the wound cavity model at 2.5, 5, 7.5, and 10 L min−1 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 5cm below, and after exposure to fluid.
Results: With the multi-perforated 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, Wilcoxon's test), 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−1, and 0.7% at 10Lmin−1.
Conclusions: For efficient de-airing, CO2 has to be delivered from within the wound cavity. The gas-diffuser was the most efficient device. In contrast to a gas-diffuser, a multi-perforated catheter or a gauze sponge is unsuitable for CO2 de-airing since they will stop functioning when they get wet in the wound.
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2 Persson M, van der Linden J. De-airing of a cardiothoracic wound cavity model with carbon dioxide: theory and comparison of a gas diffuser with conventional tubes. J Cardiothorac Vasc Anesth
3 Svenarud P, Persson M, van der Linden J. The effect of CO2
insufflation on the number and behaviour of air microemboli in open-heart surgery. Circulation
(accepted for publication).