Paradoxical response to the vasodilators.

A 52-year-old male was admitted to the hospital in congestive heart failure. Mitral stenosis as well as an aortic valve prosthesis were the underlying cardiac abnormalities. A Swan-Ganz catheter was inserted and various vasodilators were administered. Phentolamine, nitrates, nitroprusside, and hydralazine all produced an unexpected and at times an alarming increase in the pulmonary artery pressure. The explanation of this paradoxical hemodynamic response is unknown but demonstrates the importance of hemodynamic monitoring with vasodilator therapy