Objective    To find out the cause of lung injury due to hemorrhagic shock and resuscitation

and the mechanism of propofol protecting Rhesus macaques from lung injury.     Methods    Twelve healthy Rhesus macaques were randomly divided into two groups: propofol group and control group. The animal model was made by 2-hour hemorrhagic shock and 2-hour resuscitation. Rhesus macaques in propofol group were given propofol at a plasma concentration of 8 mg/L all through by the technique of target controlled infusion. Hemodynamic parameters

gas analysis and RBC

WBC

HB and PLT contents from collected arterial blood were respectively determined before bleeding

2 h after hemorrhagic shock and 2 h after resuscitation.     Results    Mean pulmonary arterial pressure and pulmonary vascular resistance index in propofol group 2 h after hemorrhagic shock and 2 h after resuscitation were significantly lower than those in control group (P0.05)

while the platelet count in propofol group was higher than that in control group (P0.01). WBC count in propofol group 2 h after resuscitation was significantly less than that in control group (P0.01).     Conclusion    Pulmonary hypertension and systemic inflammatory response may cause lung injury in Rhesus macaques during shock and resuscitation. Propofol can remarkably relieve the lung injury by ameliorating pulmonary circulation and alleviating systemic inflammatory response.