The Annals of thoracic surgery
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To analyze quantitatively the performance of the intravenacaval blood gas exchanger (IVOX), we developed a right atrium-pulmonary artery venovenous extracorporeal bypass circuit. Oxygen transfer and carbon dioxide removal were calculated at different blood flow rates, different hemoglobin levels, and during permissive hypercapnia. Oxygen transfer increased linearly with blood flow up to 41 mL/min. ⋯ Carbon dioxide removal was 45 mL/min at blood carbon dioxide tension of 42 mm Hg but increased to a maximum of 81 mL/min at a carbon dioxide tension of 90 mm Hg. We conclude that IVOX is a diffusion-limited device dependent on blood flow, hemoglobin content, and the gas pressure gradient across the membrane. Further engineering improvements are needed to improve the gas exchange performance of IVOX.
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Clinical Trial
Retrograde warm blood cardioplegia preserves hypertrophied myocardium: a clinical study.
The ability of retrograde warm blood cardioplegia to preserve hypertrophied myocardium remains controversial. This two-part study was undertaken to address this question in patients subjected to aortic valve replacement for calcified aortic valve stenosis complicated with echocardiographically defined left ventricular hypertrophy. Part 1 was designed to assess the intraoperative patterns of myocardial oxidative metabolism in 20 patients in whom the severity of left ventricular hypertrophy was reflected by a mean (+/- standard error of the mean) myocardial mass index of 213 +/- 15 g/m2. ⋯ The results of part II show that the clinical outcomes of warm patients were overall good and not different from those of the cold group. We conclude that retrograde warm blood cardioplegia can adequately preserve hypertrophied myocardium by keeping its metabolism predominantly aerobic during aortic cross-clamping provided that measures are taken to optimize the determinants of the oxygen demand/supply ratio throughout. These measures include avoidance of left ventricular distention, immediate ablation of any recurring activity during arrest, maintenance of high retrograde flow rates, limitation of hemodilution, and uninterrupted mode of cardioplegia delivery.
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Chylothorax, a potentially lethal disorder that may cause profound respiratory, nutritional, and immunologic complications, has become increasingly common in recent years. Medical therapy has been found to have a significant failure rate. Therefore, surgical treatment of complicated chylothorax has become a mainstay of care. ⋯ In 2 cases, a video-assisted thoracic operation was used in conjunction with pleuroperitoneal shunting: a previously placed pleuroperitoneal shunt that was malfunctioning was repositioned thoracoscopically after a pleural adhesiolysis, and a pleural adhesiolysis was performed thoracoscopically before placement of a pleuroperitoneal shunt. In all cases the effusion resolved after the video-assisted thoracic operation without further intervention. Video-assisted thoracic surgery offers an effective means of treating chylothorax, regardless of cause, allowing the advantage of access to thoracic structures without the morbidity of more extensive procedures.
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Long-term survival at our institution for postcardiotomy cardiogenic shock patients supported with the BioPump is 36% (29/80 patients). A heparin-coated extracorporeal membrane oxygenator (ECMO), first introduced in 1991, may reduce organ injury associated with cardiopulmonary bypass. The device can be employed rapidly because it connects directly to the cardiopulmonary bypass cannula. ⋯ Extracorporeal membrane oxygenation without left ventricular drainage clearly is not effective in patients undergoing mitral valve operations as it does not effectively decompress the left ventricle, but it was highly effective in treating postcardiotomy cardiogenic shock in our coronary artery bypass grafting patients. Extracorporeal membrane oxygenation also proved to be safe as the patient-related complications of stroke, renal failure, and mediastinitis were low. Our preliminary success with heparin-coated ECMO now needs to be confirmed by studies from other centers with larger groups of patients.
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The laterolateral anastomosis between the superior vena cava and the pulmonary artery trunk is presented as a modified technique for total cavopulmonary connection. This procedure was successfully performed on a 9-year-old girl, associated with the exclusion of the right atrium, for the treatment of tricuspid atresia and transposition of the great arteries.