The Annals of thoracic surgery
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Size limitations and technical barriers prohibit the use of many conventional mechanical circulatory support systems for postcardiotomy ventricular dysfunction in pediatric populations. Extracorporeal membrane oxygenation (ECMO), frequently used to treat neonatal respiratory failure, can provide cardiac support and is effective treatment of postoperative myocardial failure in children. From 1981 to 1987, 10 patients aged 2 days to 5 years were maintained on ECMO for 15 to 144 hours (mean duration, 92 +/- 16 hours) after cardiotomy. ⋯ There were 3 deaths; 1 was caused by cardiac and acute renal failure complicated by sepsis two days after decannulation, another occurred 19 days after atrioventricular septal defect repair, and 1 was caused by massive pulmonary hemorrhage. Major hemorrhage developed in 3 patients while on ECMO; 2 required premature decannulation for mediastinal bleeding from operative sites and ultimately survived, and 1 died of respiratory failure as a result of endobronchial bleeding. We conclude that the use of ECMO in pediatric populations for transient postoperative ventricular dysfunction improves survival with limited overall morbidity.
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To evaluate the physiological changes that occur after temporary occlusion of the superior vena cava, we clamped the vena cava for one hour in 6 cynomolgus monkeys, monkeys with a venous system most resembling that of humans. The data from arterial blood gas analysis, ie, pH, arterial oxygen tension, arterial carbon dioxide tension, and HCO3-, were within normal limits during and after occlusion of the superior vena cava. Intracranial pressure was 8.6 +/- 0.8 mm Hg (mean +/- standard error) before occlusion and rose to 22.1 +/- 2.2 mm Hg during clamping. ⋯ The electroencephalogram and electrocardiogram showed no abnormalities in this experiment. In conclusion, one-hour clamping of the superior vena cava with the azygos vein ligated was safe in 6 cynomolgus monkeys. We believe that in the clinical setting, one-hour occlusion of the superior vena cava would result in findings similar to those in this study, unless particular complications, such as arteriosclerosis or a cerebrovascular disorder, exist.
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Life-threatening tension pneumothorax in neonates on extracorporeal membrane oxygenation (ECMO) has been associated with an increase in arterial oxygen tension and a decrease in peripheral perfusion, followed by a decrease in ECMO flow with progressive hemodynamic deterioration. To investigate this triad, chest tubes were placed bilaterally in 9 dogs to allow injection of air to produce tension pneumothorax. Six dogs were subsequently placed on standard venoarterial ECMO before the reinduction of tension pneumothorax. ⋯ Each of the 6 dogs on ECMO demonstrated the triad of increased arterial oxygen tension (92 +/- 7 to 325 +/- 20 mm Hg; p less than 0.05), decreased peripheral perfusion (as evidenced by a decrease in pulse pressure from 55 +/- 4 to 31 +/- 5 mm Hg; p less than 0.05), and decreased mixed venous oxygen saturation (71% +/- 3% to 22% +/- 2% saturation; p less than 0.05) followed by a lower ECMO flow with progressive hemodynamic deterioration (oxygen delivery decreased from 285 +/- 11 to 111 +/- 12 mL/min; p less than 0.05). Aspiration of the intrathoracic air allowed return to baseline ECMO flow and hemodynamic stability in all dogs. The triad of increased arterial oxygen tension and decreased peripheral perfusion (as evidenced by a lower arterial pulse pressure and lower mixed venous oxygen saturation) followed by decreased ECMO flow with progressive hemodynamic deterioration consistently appears when tension pneumothorax occurs on ECMO.