Observation On The Effect Of Propofol On Protecting Rhesus Macaques From Lung Injury During Hemorrhagic Shock And Resuscitation

Part I Effect of Propofol on Rhesus Macaques' Pathological change during Hemorrhagic Shock and ResuscitationObjective: This investigation was aimed at evaluating the protective efficacy of propofol from lung injury on Rhesus Macaques during hemorrhagic shock and resuscitation, and finding out the probable mechanisms and factors participating in the occurrence of acute lung injury through observing the change of pathological parameters as guidelines for clinical work. Methods: 16 healthy Rhesus macaques were randomly divided into : ? Rhesus macaques were killed directly after anesthetized with thiopental; (2)2 Rhesus macaques were killed just after 2 hours' shock as result of bleeding; ﹕hock/resuscitation group (control group CG:6 Rhesus macaques);?shock/resuscitation + propofol group(propofol group PG:6 Rhesus macaques). After all Rhesus macaques except the macaques killed directly were anesthetized with thiopental, trachea intubation and invasive monitoring of blood pressure was carried out through the femoral artery while hemodynamic parameters were monitored througha Swan-Ganz tube by the way of thermodilution. Main steps in the experimental) 2 Rhesus macaques were killed directly as normal result after anesthetized with thiopental; (2) 2 Rhesus macaques were killed just after 2 hours' shock (mean arterial pressure=40 + 5 mmHg) as result of bleeding (3) The CG Macaques were bled quickly through the right femoral artery till the mean arterial pressure was 40?mmHg at shock. 2 hours later, the total amount of blood and saline 2 fold volume of blood lost was reinfused quickly. Another 2 hours later they all were killed. (4)The process of PG was same to that of CG except that the PG Rhesus macaques were given propofol at a plasma concentration of 8mg/L all through by the technique of target controlled infusion. Determination carried out in the experiment incIuded:〩emodynamic parameters, gas analysis and RBC, WBC, HB and PLT contents from collected arterial blood separately before bleeding, 2 hours after hemorrhagic shock and 2 hours after resuscitation. 〢s soon as the Rhesus Macaques were killed, samples of lung tissue were taken to be observed under light microscope and electronic microscope for changes of lung tissue and determination of water-to-dry weight ratio. Results: (l)The lung constitution of 2 Macaques killed directly was normal, and the water-to-dry weight ratio (W/D) of the lung was 5.545 + 0.191; (2)Contrast to that of normal Macaques, the lung constitution of 2 shock macaques had not remarkable change. The W/D of the lung was 5.655 + 0.474; (3)The Mean pulmonary arterial pressure (MPA) and pulmonary vascular resistance index (PVRI) of the CG at 2 hours after hemorrhagic shockand 2 hours after resuscitation were significantly higher than those of the PG(p<0.05), while the platelet of the CG was less than that of the PG(p<0.05). White blood cell count of the CG 2 hours after resuscitation was significantly higher than that of the PG O<0.05), as well as the W/D of the lung. (2) The observation on lung tissue under light microscope showed that pulmonary edema of the CG was more serious than that of the PG. Observations on the lung tissue under electronic microscope confirmed that the lung injury of the CG was more serious than that of the PG. Conclusion: Propofol can remarkably relieve the lung injury occurring during hemorrhagic shock and resuscitation stage by ameliorating pulmonary circulation and has effect on the white blood cell.