Anaesthetic management of high-risk cardiac patients undergoing thoracic surgery with the support of intra-aortic balloon pump.

shorter than SGE, as a limited amount of N2O is washed out with a high concentration gradient between blood and alveolar space, especially when ventilation is with an open circuit. Interestingly, we found greater changes in arterial PaO 2 between the first gas mixture and AIRs, independent of whether it had been nitrous oxide/oxygen or AIRc/oxygen (Fig. 1). By altering from AIRs to AIRc or nitrous oxide, much less effect on the PaO 2 was produced compared with the above sequence. Obviously, the withdrawal of the low nitric oxide concentrations induces a mismatching in the lungs that cannot be reversed by similar concentrations of nitric oxide. Sometimes new results raise more questions than answers.