The Annals of thoracic surgery
-
Comparative Study
Comparison of bioimpedance and thermodilution methods for determining cardiac output: experimental and clinical studies.
The changes in electrical bioimpedance caused by the blood flow through a thoracic segment may be measured using a series of electrodes placed at opposing ends of this segment. Cardiac output (CO) is calculated by computer as the change in bioimpedance over time. This study was performed to determine the accuracy of bioimpedance CO (CObi) compared with standard thermodilution CO (COtd) in an animal model and in patients. ⋯ CObi became inaccurate with severe tachycardia (pulse, 180/min), low CO, or frequent arrhythmias. These results indicate that this technique provides a continuous noninvasive method of determining CO that is comparable with thermodilution techniques. The technique of CObi holds promise for widespread use when continuous and noninvasive monitoring of CO is necessary.
-
Aortic stenosis accounts for 5 to 6% of infants and children seen for surgical repair of congenital heart disease. The clinical presentation and reported results of operation for aortic stenosis are highly variable. This retrospective review was undertaken to assess our operative mortality and the degree of gradient reduction afforded by each of several surgical techniques used to treat aortic stenosis in children over a 30-year period. ⋯ Twenty-nine (13%) of the 223 long-term survivors have undergone a subsequent procedure for relief of residual or recurrent obstruction; 12 have had insertion of an aortic valve prosthesis, 12 have had insertion of an apicoaortic conduit, and 6 have required repeat aortic valvotomy. These data demonstrate the low operative mortality and excellent hemodynamic benefit of surgical relief of single-level aortic stenosis in children older than neonates. Conduits placed for complex obstructions or operative procedures in neonates have acceptable hemodynamic benefits, but operative mortality remains high.