2005 OPEN FORUM Abstracts
INHALED NITRIC OXIDE FOR ACUTE RIGHT VENTRICULAR DUYSFUNCTION AFTER EXTRAPLEURAL PNEUMONECTOMY
Evans R. Fernandez, MD; Mark T. Keegan, MB; Barry A. Harrison, MB BS Mayo Clinic, Rochester, MN and Jacksonville, FL
Introduction: The influence of a pneumonectomy on the development of acute right ventricular failure (RVF) is significant and frequently under recognized. Inhaled nitric oxide (INO) may help with management.
Case Summary: A 41-year-old woman presented with a malignant mesothelioma diagnosed following a Chamberlain procedure. Five months of chemotherapy led to tumor shrinkage. Echocardiography was normal. Due to pleural, pericardial and chest wall involvement by the tumor she underwent extrapleural pneumonectomy. On postoperative day 9, while in the step-down unit, the patient developed progressive dyspnea. A chest film showed a large left hydropneumothorax and chest tube insertion yielded 1700 mLs of serosanguinous fluid. Four hours later cardiac arrest occurred and pulseless electrical activity was diagnosed. Resuscitative efforts included intubation and ventilation, chest compressions, fluid administration and the use of pressor medications including epinephrine. In the intensive care unit, while on intravenous epinephrine infusion and with a pulmonary artery catheter in situ, echocardiography was performed. The right atrium and ventricle were massively enlarged with marked reduction in right ventricular systolic function. Left ventricular and valvular functions were normal. Chest radiograph showed a small left pleural effusion. Cardiac enzymes and electrocardiograph did not reveal myocardial infarction. INO and dobutamine were started with subsequent decrease in pulmonary vascular resistance and improvement in cardiac index (Table). The patient was weaned from pressor medications over the next 24 hours and the INO was discontinued 60 hours after initiation. Echocardiography performed three weeks after her cardiac arrest showed normal right ventricular size and function. She left the hospital in stable condition 6 weeks after the surgery.
Discussion: Unrecognized acute RVF and concurrent hypovolemia has a poor prognosis because the limited contractile reserves of the right ventricle. INO decrease right ventricular afterload and improve cardiac index by selectively decreasing pulmonary vascular tone. Inotropic agents work synergistically with the gas to augment right ventricular performance.
Table. Changes in hemodynamic data before and after administration of INO
|Parameter||Immediately before INO||After 20 mins||After 13 hrs||After 24 hrs||After 30 hrs|
|SVRI, dynes.sec/cm5/ m²||5594||3256||1907||1855||2360|
|PVRI, dynes.sec/cm5/ m²||593||258||121||108||70|
CVP: central venous pressure. PAP: pulmonary artery pressure, MAP: mean arterial blood pressure, CI: cardiac index, SVRI: systemic vascular resistance index, PVRI: pulmonary vascular resistance index, INO: Inhaled Nitric Oxide.