高原出血性休克血流动力学变化

Hemodynamic Changes of High Altitude Hemorrhagic Shock

9只海拔3658米的高原羊在2小时失血期,心泵和等容期收缩和舒张功能降低,回输血后恢复正常,提示此时心功能降低是前负荷降低所致。回输血后2小时,心指数、每搏指数首先减少,继之动脉压、左室dp/dtmax减少,舒张末压和T值延长,最后出现右室舒张末压升高和右室dp/dtmax下降,这表明双心室功能障碍是心肌收缩性下降所致,左室先于右室功能受损。回输血3小时开始出现肺血管阻力和肺动脉压升高。

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.