Resuscitation Strategy Of Blast-related Hemorrhagic Shock

Objective:A stable and reliable animal model of blast-related hemorrhagic shock in SD rats was established.The SD rat blast injury combined with 30%total blood volume(TBV)hemorrhagic shock through different resuscitation time points,resuscitation methods,and types of resuscitation fluids to explore the resuscitation strategy of blast-related hemorrhagic shock.Methods:1.Observation on the characteristics of blast injury combined with 30%TBV hemorrhagic shock in SD rats.The healthy SD rats were selected.Femoral artery and vein catheterization.The rats were randomly divided into a 5.0MPa blast injury,30%blood loss,5.0MPa blast injury combined with 30%blood loss,a surgical control and a normal control group.BST-Ⅰwas used to blast with different driving pressures,and blood was drawn from the femoral artery in the four groups respectively.Observe the rats after injury.Killed them after 24 hours.2.Fluid resuscitation for blast-related hemorrhagic shock in SD rats.Based on the previous part of the experiment.The SD rat model of 5.0MPa blast injury combined with 30%blood loss was selected.Perform the fluid resuscitation experiments:(1)Blast-related hemorrhagic shock fluid treatment time-effect research groups:the healthy SD rats randomly divided into 0.5h,2h,4h routine saline treatment groups(3 groups).Fluid resuscitation was started with twice the blood loss of normal saline at 0.5h,2h,and 4h after injury.The resuscitation fluid was pumped intravenously with an infusion pump at a flow rate of 30ml/h.Followed by observation and recording.Killed the rats after 24 h.Each blast-related hemorrhagic shock group has a single shock resuscitation control group(3groups),the healthy SD rats,no blast injury,the rest of the treatment is the same.(2)Evaluate the effectiveness of routine and restricted fluid resuscitation research groups:the healthy SD rats were randomly divided into 0.5,2 and 4 h 2/3 the amount of saline treatment groups(6 groups).After injury,the fluid resuscitation was started with normal saline at 2/3 times and 1 time the blood loss at 0.5h,2h,and 4h.The resuscitation fluid was pumped intravenously with an infusion pump at a flow rate of 30ml/h.Followed by observation and recording.Killed the rats after 24 h.Each blast-related hemorrhagic shock group has a single shock resuscitation control group(6 groups),the healthy SD rats,no blast injury,the rest of the treatment is the same.(3)The relationship between liquid types and effect of blast-related hemorrhagic shock fluid resuscitation research groups:the healthy SD rats were randomly divided into 7.5%sodium chloride solution,sodium lactate Ringer’s injection,Voluven(hydroxyethyl starch 130/0.4 sodium chloride injection),autologous blood 0.5,2,4h treatment groups(12 groups).After injury,the fluid resuscitation was started at 0.5h,2h and 4h with 7.5%sodium chloride solution 4ml/kg,sodium lactate Ringer’s injection 2/3 times blood loss,Voluven 4ml/kg,and autologous blood Resuscitation fluid was pumped intravenously using an infusion pump at a flow rate of 30 ml/h.The rats were observed.Each group of blast-related hemorrhagic shock has a single shock resuscitation control group(12 groups),the healthy SD rats,no blast injury,the rest of the treatment is the same.Results:1.Establishment of the blast-related hemorrhagic shock animal model.The 8h and 24h survival rates of the blast injury combined with 30%blood loss group were 66.67%and 59.26%,respectively.The lung injury of blast-related hemorrhagic shock was more serious than that in the simple blast injury(P>0.05).The lactic acid in blast-related hemorrhagic shock was higher than that of other groups(P>0.05).It was found that the mortality of rats with MAP≥100mm Hg after injury was higher than that of MAP<100mm Hg after injury(P<0.05).The lung water content of rats in this group gradually decreased to normal levels over time,and MAP and heart rate were lower than normal levels,and gradually increased over time.2.Fluid resuscitation for blast-related hemorrhagic shock in SD rats.(1)Blast-related hemorrhagic shock fluid treatment time-effect research:Compared with the 5.0MPa blast injury combined with 30%blood loss group,the untreated group.The 8-hour survival rate of the blast-related hemorrhagic shock in the 0.5,2,and 4 hours routine saline treatment group was lower than that of the 5.0MPa blast injury combined with 30%blood loss group.There is no statistical difference(P>0.05).The survival rate of the routine saline treatment group was lower than that of the untreated group.Routine saline with twice the blood loss did not raise blood pressure to a normal level,which was slightly lower than the normal blood pressure level.(2)Evaluate the effectiveness of routine and restricted fluid resuscitation research:The cumulative survival rate in the first 8 hours of the blast-related hemorrhagic shock of2,4 hours normal saline treatment group was higher than that of theblast injury combined with 30%blood loss group.There was no statistical difference(P>0.05).After resuscitation,blood pressure returned to slightly lower than normal blood pressure level.The cumulative survival rate of the blast-related hemorrhagic shock 0.5h and 2h normal saline treatment groups in the first 8 hours was higher than the blast injury combined with 30%blood loss group.The survival rate of the 0.5h and 2h treatment group was better than that of the untreated group.There was no statistical difference(P>0.05).After resuscitation,blood pressure returned to slightly lower than normal blood pressure level.(3)The relationship between liquid types and effect of blast-related hemorrhagic shock fluid resuscitation research:The 8-hour cumulative survival rate of the blast-related hemorrhagic shock 0.5,2h 7.5%sodium chloride solution 4ml/kg treatment group was higher than the blast injury combined with 30%blood loss group,and the survival rate of the 0.5h treatment group was statistically different(χ~2=4.701,P=0.030).The 8-hour survival rate in the 4h treatment group was lower than 5.0MPa with blast injury and 30%blood loss.After resuscitation the blood pressure returned to slightly lower than normal blood pressure level.Lactic acid in blood gas:blast injury combined with hemorrhagic shock 2h treatment group<0.5h treatment group<no treatment group<4h treatment group.Within 8 hours after injury,the cumulative survival rate of the 0.5-hour lactated Ringer’s solution treatment group with blast-related hemorrhagic shock was higher than that of the blast injury combined with 30%blood loss group.But there was no statistical significance(P>0.05).After resuscitation the blood pressure returned to slightly lower than normal blood pressure level.Lactic acid in blood gas:blast injury combined with hemorrhagic shock 0.5h treatment group<4h treatment group<no treatment group<2h treatment group.The cumulative survival rate of the shock injury combined with hemorrhagic shock 0.5,2,4h Voluven 4ml/kg treatment group within 8 hours after injury were higher than the blast injury combined with 30%blood loss group.But there was no statistical significance(P>0.05).After resuscitation the blood pressure returned to slightly lower than normal blood pressure level.Lactic acid in blood gas:blast injury combined with hemorrhagic shock 0.5h treatment group<2h treatment group<no treatment group<4h treatment group.Within 8 hours after injury,the cumulative survival rate of the 0.5,2,and 4h autologous blood treatment groups of blast-related hemorrhagic shock were higher than that of the blast injury combined with 30%blood loss group,and the 0.5h and 2h groups had statistical significance(χ~2=10.03,P=0;χ~2=4.91,P=0.03).The blood pressure returned to normal blood pressure level after resuscitation.Lactic acid in blood gas:blast injury combined with hemorrhagic shock 2h treatment group<0.5h treatment group<4h treatment group<no treatment group.Conclusion:1.SD rats are injured by blast and hemorrhagic two factors.Compound injuries are more serious than those caused by a single factor,and the mortality rate is significantly increased.2.According to the data analysis of the established model,it was found that the mortality rate of rats with MAP≥100mm Hg after injury is higher than that of rats with MAP after injury<100mm Hg.It is suggested that there may be misjudgment in the measurement of blood pressure in the treatment for the blast-related hemorrhagic shock.The early blood pressure of the blast-related hemorrhagic shock may be normal or slightly lowered or raised.At this time,it does not mean that they have no shock,but the situation is more serious.It is critical and needs to deal with in time.The specific mechanism needs further study.3.In the treatment of blast-related hemorrhagic shock,(1)the different liquids have different treatment time windows:isotonic crystalloids,which have a therapeutic effect within2 hours;Hypertonic crystalloids have a therapeutic effect within 2 hours;Artificial colloidal fluid has a therapeutic effect within 4 hours;Blood and its products have a therapeutic effect within 4 hours.(2)The therapeutic effect of restricted resuscitation is better than that of routine resuscitation.(3)Different liquids have different therapeutic effects:autologous blood>Voluven>7.5%sodium chloride solution>normal saline.4.The fluid resuscitation strategy for blast-related hemorrhagic shock is that try to use fluid resuscitation within 4 hours after injury.If use crystal fluid only,try within 2 hours after injury.The amount of fluid replacement should not exceed the amount of blood loss.Priority is given to blood and its products,followed by artificial colloids,and then 7.5%sodium chloride solution.It is not recommended to use normal saline or lactated Ringer’s solution.A single crystal should not be used for resuscitation beyond 2 hours.