| Part 1 Study on the Early Changes of Coagulation Function after Traumatic Liver and Spleen Hemorrhage in Hot and Humid ConditionsObjective: The regularity and characteristics of the early coagulation function in Bama miniature pig models of uncontrolled traumatic liver and spleen hemorrhage under the hot and humid environment were compared with those under the normal environment,so as to provide reference for the clinical treatment for patients with severe traumatic bleeding under hot and humid environment,and to provide stable and repeatable animal models of traumatic shock for subsequent relevant studies.Methods: Twelve Bama miniature pigs were randomly divided into two groups.In the normal environment group,the temperature and relative humidity were set at 22.0±1.0℃and 45±5% respectively.And the temperature and the relative humidity of the hot and humid environment group were set at 39.0±1.0℃ and 90±5%,respectively.The two groups of experimental animals were respectively placed in the artificial meteorological laboratory chamber with corresponding temperature and humidity.After 3 hours of exposure,the uncontrolled traumatic liver and spleen hemorrhage models were established as follows:Twelve Bama miniature pigs were anesthetized and entered into the abdominal cavity via laparotomy.About 5cm of the distal of the spleen was cut off,and the distal splenic arteriovenous was cut off at the corresponding location.After bloodletting to 30% of the total blood volume,the splenic arteriovenous was ligated.Creating continuous intraabdominal bleeding models through a 2cm deep and 10 cm in length incision on the left lateral lobe of the liver.Abdominal negative pressure drainage was placed and no fluid resuscitation was administered.Blood loss,heart rate and mean arterial pressure(MAP)were recorded before injury(baseline),immediately after injury,15 min,30min,45 min,60min,90 min,and 120 min after injury respectively.and arterial blood was collected at each time point for arterial blood gas analysis.Venous blood was collected for blood routine examination,conventional coagulation tests(CCT)and Thrombelastography(TEG)tests.Results: Compared with the normal environment group,the blood loss was increased(33.0±1.2m L/kg VS 35.4±1.1m L/kg)and the MAP decreased to a lower level(36.8±2.0mm Hg VS 32.3±2.9mm Hg)in hot and humid environment group.The lactate in the hot and humid environment group increased by about 5 times and that in the normal environment group increased by about 4 times at 120 min after injury,and the PH showed a decreasing trend after injury.The PH in the hot and humid environment group was significantly lower than that in the normal environment group at 45 min and 120 min after injury,and the hemoglobin concentration,platelet count and serum ionized calcium showed an overall decreasing trend after blood loss,with no significant difference between the two groups.PT,APTT and D-dimer in both groups showed a significant increasing trend after injury,while fibrinogen concentration showed a decreasing trend with time,indicating that the body was in a state of hypocoagulation.Contrary to the CCT test,we observed that R time and K time were shortened within 120 min after injury,angle α was increased,and maximum amplitude(MA)was significantly decreased in both groups,indicating that the body was in a hypercoagulable state but the clot strength was decreased.The PT and APTT in the hot and humid environment group were longer than those in the normal environment group;the D-dimer increased and MA decreased more significantly,indicating that the environmental factors of high temperature and humidity can worsen the coagulation function after trauma.Conclusions: The animal models of uncontrolled traumatic liver and spleen hemorrhage in our study were relatively reliable and repeatable.The changes of coagulation function after severe traumatic bleeding in the hot and humid environment are more complicated,with reduced clot intensity and increased bleeding risk.Patients require closer monitoring and timely adjustment of treatment under this condition.TEG can be used as a more accurate and sensitive means for monitoring and treatment of ATC.Part 2 Effects of Different Resuscitation Strategies on Bleeding and Coagulation Function after Traumatic Liver and Spleen Hemorrhage in Hot and Humid ConditionsObjective: Establish the Bama miniature pig models of uncontrolled traumatic liver and spleen hemorrhage,compare the effects of hypotensive resuscitation strategy and positive fluid resuscitation strategy on bleeding indicators and coagulation function in the hot and humid environment,and explore the applicability of hypotensive resuscitation strategy in the humid and hot environment.Methods: Twelve Bama miniature pigs were randomly divided into hypotensive resuscitation group and positive fluid resuscitation group.The experimental animals were placed in the artificial meteorological laboratory chamber in a hot and humid environment(the temperature was 39.0±1.0℃ and the relative humidity was 90±5%).After exposure for3 hours,the uncontrolled traumatic liver and spleen hemorrhage models were established.Twelve Bama miniature pigs were anesthetized and entered into the abdominal cavity via laparotomy.About 5cm of the distal of the spleen was cut off,and the distal splenic arteriovenous was cut off at the corresponding location.After bloodletting to 30% of the total blood volume,the splenic arteriovenous was ligated.Creating continuous intraabdominal bleeding models through a 2cm deep and 10 cm in length incision on the left lateral lobe of the liver.Abdominal negative pressure drainage was placed.Resuscitation with lactated Ringer’s at 30 min after injury.The target systolic blood pressure was maintained at 80 to 90 mm Hg in the hypotensive resuscitation group and at 110 to 120 mm Hg(or MAP > 80 mm Hg)in the positive fluid resuscitation group.Blood loss,heart rate and final fluid requirement were recorded before injury(baseline),immediately after injury(0min),30min(beginning of resuscitation),60 min,90min,120 min,150min and 180 min after injury,and arterial blood was collected at each time point for arterial blood gas analysis.Venous blood was collected for blood routine examination,conventional coagulation tests(CCT)and Thrombelastography(TEG)tests.Results: The blood loss increased,heart rate and lactate decreased after resuscitation in two groups,indicating improved circulation volume and tissue perfusion;PH further decreased after resuscitation,indicating that acidosis persisted and worsened;platelet count and hemoglobin concentration showed a downward trend because of the liquid dilution after resuscitation;and serum ionized calcium increased after resuscitation.At the end of the experiment,the requirement of lactated Ringer’s was 95.3±4.6m L/kg in the hypotensive resuscitation group and 154.0±5.9m L/kg in the positive fluid resuscitation group.Compared with the positive fluid resuscitation group,the experimental animals in the hypotensive resuscitation group had less bleeding(36.2±0.7m L/kg VS 39.7±1.0m L/kg).The lactate decreased significantly,but the PH was lower and the degree of acidosis was more severe in the hypotensive resuscitation group.The results of CCT showed that the fibrinogen concentration decreased with time,which was lower in the positive fluid resuscitation group than in the hypotensive resuscitation group.PT increased significantly with time in both groups,and which was higher in positive fluid resuscitation group.APTT and D-dimer increased after resuscitation,but no significant difference was found between two groups.In TEG detection,the K time and R time of the two groups were prolonged after resuscitation,and the Angle α increased slowly after resuscitation,and there was no significant difference between the two groups.MA decreased significantly before resuscitation and increased after resuscitation with time in hypotensive resuscitation group,while MA had no significant change in positive fluid resuscitation group after resuscitation,indicating that hypotensive resuscitation was conducive to the recovery of clot strength.Conclusions: This study preliminary confirmed that hypotensive resuscitation strategy was also applicable in the hot and humid environment.Compared with positive fluid resuscitation strategy,hypotensive resuscitation strategy can significantly reduce the amount of blood loss,promote lactate metabolism and improve the coagulation function in experimental animals with severe traumatic bleeding. |
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