Introduction: During cardiac surgery the wound is exposed to desiccation, in particular as a result of operating room ventilation and because dry carbon dioxide is sometimes insufflated for de-airing. The objectives were to quantify and compare the desiccation rates during these conditions, and to determine the influence of insufflation of humidified carbon dioxide.
Method: In a fully ventilated operating room we studied humidity (Hygropalm3, RotronicAG, Switzerland) and desiccation rate of a cardiothoracic wound model, which included two standard blood agar plates. We compared the effect of dry and humidified carbon dioxide (bubbled through sterile water), respectively, with a control. Gas was supplied to the model at 10 L min−1 via a standard open-ended tube or a low velocity-outlet device (a gas-diffuser), and we also compared the effect of these two delivery systems.
Results: The accumulated water loss mg (cm2)−1 in the model increased almost linearly with time, irrespective of the humidity of the gas or the vehicle for its supply (R2 = 0.97). Significant differences appeared between the five groups as to their desiccation rate (water loss expressed in mg (cm2 min−1)−1, i.e., the inclination of the water loss curves (P < 0.001, Wilcoxon's test). Dry (3%) and humidified (76%) carbon dioxide insufflation via the openended tube resulted in much higher rates than the control. When insufflated via a gas-diffuser, dry carbon dioxide gave a slightly higher desiccation rate but humidified carbon dioxide lowered the rate to <10% of the control.
Conclusions: Humidified carbon dioxide may be used to avert desiccation of the cardiothoracic wound. The humidified gas is effective only when delivered via a low-velocity outlet device.
1 Svenarud P, Persson M, van der Linden J. Intermittent or continuous carbon dioxide insufflation for de-airing of the cardiothoracic wound cavity? An experimental study with a new gas-diffuser. Anesth Analg
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. Efficiency of a gas-diffuser and influence of suction in carbon dioxide deairing of a cardiothoracic wound cavity model. J Thorac Cardiovasc Surg