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Efficacy of the FEF colorimetric end-tidal carbon dioxide detector in children.

The critical problem in parturients with aortic stenosis is the inability to maintain adequate cardiac output in the presence of decreased systemic vascular resistance. Sympathetic blockade associated with epidural anesthesia can cause decrease in ventricular preload and a decrease in the diastolic aortic-left ventricular pressure (coronary perfusion pressure) gradient leading to sudden cardiac failure. In our case, the absence of such cardiac decompensation with the use of epidural anesthesia might be attributed partly to the fact that there was no increase in the left ventricular pressure, as indicated by normal size of the left ventricle. When mitral and aortic stenoses co-exist, the clinical features of mitral stenosis usually predominate and the features of aortic stenosis may not be evident (4). The co-existing mitral stenosis reduces left ventricular filling, resulting in decreased cardiac output and the absence of left ventricular hypertrophy. Thus, the use of epidural anesthesia in our case with multivalvular stenosis seemed to be as beneficial as in the parturient with mitral stenosis alone. Nevertheless, we would like to mention that with more severe stenotic valvular disease or significant clinical features of aortic stenosis the benefits of epidural anesthesia should be weighed against the potential risks of decreases in venous return and systemic vascular resistance. Young K. Shin, MD Jeffrey c. King, MD Departments of Anesthesia and Obstetrics and Gynecology School of Medicine Georgetown Uniziersity Washington, DC 20007