Abstract
Left heart bypass is beneficial procedure for the operation of the thoracic aneurysm, but its hemodynamic control has not been studied. We conducted an experiment of the left heart bypass in dogs, using a newly designed compact centrifugal pump, instituted from the left atrium to the left femoral artery. After the start of bypass, total descending aorta was clamped and, there-after, cardiac output, left renal flow, systolic pressure of the left carotid artery and mean pressure of the right femoral artery were measured. The pressure of the right femoral artery was well controlled by the pump flow (r=0.91). The renal blood flow was well correlated with the pressure of the left femoral artery (r=0.86) and pump flow (r=0.89). Because of renal and spinal cord protection, the pump flow should be kept more than 30 ml/min/kg. However, cardiac output and the pressure of the left carotid artery were decreased when pump flow was increased. When that increased to 100 mmHg in the right femoral artery, the pressure of the left carotid artery well correlated with that before left heart bypass had been started (r=0.76). And phentolamine mesilate (alpha-blocker) was very effective when the pressure of the left carotid artery was over 140 mmHg and was not influenced by the pump flow.
Keywords left heart bypass, thoracic aortic aneurysm, centrifugal pump, renal blood flow, hemodynamic control
