Decrease in pulmonary artery pressure after administration of thoracic epidural anesthesia in a patient with Marfan...

Thoracic epidural anesthesia is an adjunct to general anesthesia in cardiac surgery. Decrease in heart rate and blood pressure are frequently seen beneficial effects. There are several other hemodynamic effects of thoracic epidural anesthesia such as decrease in systemic vascular resistance, cardiac index, left ventricular stroke work index among others. However, the effect of thoracic epidural anesthesia on pulmonary artery pressure (PAP) has not been studied extensively in humans. Thoracic epidural anes-thesia decreased pulmonary artery pressure in experimen-tally induced pulmonary hypertension in animals. The mechanisms involved in such reduction are ill understood. We describe in this report, a significant reduction in PAP in a patient with Marfan's syndrome scheduled to under-go aortic valve replacement. The possible mechanisms of decrease in pulmonary artery pressure in the described case are, decrease in the venous return to the heart, decrease in the systemic vascular resistance, decrease in the right ventric-ular function and finally, improvement in myocardial contraction secondary to all the above. The possibility of Marfan's syndrome contributing to the decrease in PAP appears remote. The authors present this case to generate discussion about the possible mechanisms involved in thoracic epidural anesthesia producing beneficial effects in patients with secondary pulmonary hypertension. Thoracic epidural anesthesia appears to decrease pulmonary artery pressure by a combination of several mechanisms, some unknown to us. This occurrence, if studied and understood well could be put to clinical use in pulmonary hypertensives.