Study On The Significance Of Endothelin And Lactate Dynamic Changes During Hypotensive Fluid Resuscitation From Uncontrolled Hemorrhagic Shock

Objectives To investigate the significance of Endothelin and Lactatedynamic changes during Hypotensive fluid resuscitation from UncontrolledHemorrhagic Shock.Methods Severe uncontrolled hemorrhagic shocks were induced in 12healthy New Zealand rabbits by the Krausz's method of massive splenicinjury with a transection of the middle branch of splenic artery, and another 6rabbits were used as the control with the same abdominal operation but no:splenic arterial transection. When the mean arterial pressure (MAP)declinedto 40 mmHg(1 mmHg=0.133 kPa) designated as "the start of shock",resuscitation was begun with the infusion of Ringer's solution. According tothe restoration of the mean arterial pressure during resuscitation, the 18animals were randomly assigned to three groups: 1) hypotensive fluidresuscitation (MAP=40 mmHg), 2) traditional fluid resuscitation (MAP=80mmHg), and 3) non-shock control. The splenic bleeding was stopped 45minutes after the start of shock (as the end of shock). After the shock wascontrolled, resuscitation was continued with the infusion of a mixture ofRinger's solution and whole blood (in the ratio of 2:1) to further restore theMAP to 100 mmHg hopefully for 2 hours (as the end of resuscitation). Thenthe animals were continuously monitored for another 6 hours (as the end of observation). During the experiments, the arterial blood endothelin and lactatelevels were measured at the moments of the start of shock, the end of shock,the end of resuscitation, and the end of observation, respectively.Results (1). Compared to the non-shock control group, the bloodendothelin and lactate concentrations significantly increased (p＜0.05) in thehemorrhagic shock animals during both hypotensive and traditional fluidresuscitation with the peak at the end of shock. (2). For the hypotensive fluidresuscitation animals, their endothelin and lactate levels at the end of shockand the end of resuscitation were substantially higher (p＜0.05) than the valuesat the start of shock, and the elevation of endothelin concentration remainedbut the lactate variable approximately returned to the start level at the end ofobservation (p＞0.05). Whereas, in the traditional resuscitation group,following increases of endothelin and lactate levels since the start of shock,these variables reached peak at the end of shock, and then declined during theobservation period. However, at the end of observation, both endothelin andlactate concentrations were still significantly greater than the start levels. (3).There were only slight differences of the endothelin and lactate levels at thestart of shock (p＞0.05) comparing the hypotensive fluid vs. traditionalresuscitation groups. But the hypotensive resuscitated animals showed muchlower concentrations (p＜0.05) of endothelin and lactate during the followingphases of the experiments. (4). There was positive correlationship between thelevels of endothelin and lactate (p＜0.01) during each phase of theexperiments.Conclusions According to the lower Endothelin and Lactate levelsdetected in the group Hypotensive fluid resuscitation, hypotensive fluidresuscitation could improve microcirculation, elevate blood perfusion, alleviate acidosis and show the prognostic values in the evaluation ofUncontrolled Hemorrhagic shock resuscitation.