RESUMO
Hemorrhagic shock was studied in 9 sheep living and born at 3658m above sea level. It was found that cardiac pump function and isovolumic systolic and diastolic function of biventricles were reduced. There were no significant changes of peripheral and pulmonary vascular resistance as compared with the control values. After reinfused shed blood, all above parameters immediately return to the control values, the results suggest that impaired systolic and diastolic function is due to the decreased preload. Two hours after reinfused shed blood, At Ci, Si, carotide blood flow fell obviously, later mean aortic arterial pressure and dp/dtmax of LV decreased while LV diastolic pressure and T constant increased, At last dp/dtmax of RV diminished and diastolic pressure of RV raised. These results indicate that the dysfunction of biventricles may be produced by the reduced myocardial contractility, and left ventricle impaired earlier than right ventricle. Two hours after reinfused shed blood, pulmonary arterial pressure and pulmonary vascular resistance were increased but aortic arterial pressure was reduced.