Measurement of mean pulmonary blood flow (Qp) as a function of pulmonary inert gas (N2O) uptake was studied with the aid of a mathematical model, fast response measurement of gas flow and gas concentrations at the mouth, and digital computer analysis of the data. The model treats the total pulmonary inert gas uptake as the sum of dead space, alveolar, lung tissue, and pulmonary blood flow uptakes. Analysis of any two breaths during breathing of a gas mixture (39 percent N2O, 21 percent O2, 40 percent N2 or He) in terms of the soluble (N2O) and the insoluble (N2 or He) inert gas yields two simultaneous equations with two unknowns which can be solved for Qp. No assumptions are required about the magnitude of the alveloar, dead space, or lung tissue volumes and constant FRC is not a requirement. The validity of the mathematical model and its sensitivity to known measurement errors was studied by computer simulation of respiratory gas exchange for N2O and N2. Comparison of Qp (N2O) with the direct Fick method (O2) in five anesthetized dogs showed agreement within plus or minus 20 percent. The proposed method has promise as a clinical method for determination of cardiac output on a breath-to-breath basis during regular breathing at rest or during exercise.

Aneurysms of aortic arch are rare but amenable to endovascular therapy. Arch aneurysm presenting with aorto-esophageal fistula and hematemesis is a feared, but relatively rare complication. The extrapolation of the safety and rapidity of emergent endovascular repair for bleeding arch aneurysms has been infrequently reported. A bovine arch anatomy confers distinct advantages for endovascular therapy often avoiding a preceding debranching surgery. However, its endovascular treatment might be complicated by the nonhealing of fistula and potential risk for mediastinitis. Here, we report a case of a bovine aortic arch cystic aneurysm complicated by bleeding aorto-esophageal fistula, which warranted an emergent endovascular therapy. The prevertebral part of LSCA was plugged to interrupt the retrograde filling and a future endoleak. A nonhealing aorto-mediastinal fistula at follow-up was successfully treated by covered esophageal stenting. This report reiterates the importance of multidisciplinary approach with multispecialty collaboration to such complex spectrum of diseases.

Three children with repaired omphalocele underwent diagnostic cardiac catheterization. In addition to intracardiac shunts, each was found to have marked angulation at the junction of the inferior vena cava and the right atrium. After review of our autopsy material following omphalocele repair, it is suggested that the inferior vena cava - right atrial angulation is due to gradual abnormal fixation of this junction either in utero or related to the surgical repair. A change in current surgical therapy is NOT recommended. Angulation of the inferior vena cava - right atrial junction is potentially important because a) it may interfere with venous cardiac catheterization from "below", b) it poses a danger to inferior vena caval cannulation for cardio-pulmonary by-pass, and c) it may become obstructive with time producing portal hypertension.

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The incidence of eventration of diaphragm before cardiac surgery is rare. We describe the management of a patient with eventration of the diaphragm who underwent a coronary artery bypass grafting (CABG) for left main coronary artery disease followed by left diaphragm plication with video-assisted thoracic surgery (VATS) for the postoperative respiratory insufficiency.

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Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy, is a rare multisystemic disorder that was first reported by Rosai and Dorfman in 1969. It is a distinct histioproliferative disorder due to overproduction of histiocytes, which accumulate in lymph nodes. The cardiac involvement of this disease is extremely rare, and until now, only 18 cases have been reported. We report the case of a 53-year-old woman with right atrial mass mimicking myxoma, which the histopathologic evaluation revealed to be Rosai-Dorfman disease of the right atrium.

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