| Although great progress has been made in basic and clinical study of traumatic brain injury(TBI)in the recent decade,the mortality is still high,especially the poor outcome in severe TBI.Now most of the study is still focusing on the prevention and treatment of the secondary brain damage after severe TBI.The secondary intracranial hypertention(ICH) is very common after TBI.Long-time ICHexisting or the intracranial pressure(ICP) level reaching too high, it becomes a majpr factor which will deteriorate the patients' outcome. As the most common osmotic diuretics,mannitol is effective in decreasing the ICH. Intracranial hematoma in rabbits is used to simulate the acute ICH.We observed the effects of different dosage of mannitol on decreasing the ICH and the renal functions. We studied the effective and reasonal mannitol dosage. The reaseach consisys of two parts:Part I Effect of different dosages of mannitol on decreasing intracranial hypertension in animalsObjective:To study the effect and significance of different dosages of mannitol on decreasing intracranial pressure in a model of acute intracerebral hematoma in rabbits.Method:The animals were randomly signed to four groups,then intubated and mechanically ventilated.We established a model of intracerebral hematoma with injection autologus blood.The control group(n=8) receive saline while other three groups(n=8) receive 0.25g/Kg?weight,1.0g/Kg?weight,2.0g/Kg?weight of mannitol respectively.ICP,MAP and plasma osmolarity were continuously monitored before and during the protocol especially recorded at 3min,15min,30min,60min,120min and 180min after administration of different treatments.Results:The rabbit's model of acute intracerebral hematoma are successfully established and copied.All the three therapy groups can significantlydecrease the raised ICP( P<0.01 ) contrast with the control group. The three thrapy group have the similar changes. ICP is decreased immediately after using mannitol and the ICP at 3min, 15min, 30min and 60min after mannitol are significantly different from before mannitol. ( P<0.01 ) ICP at 15min after mannitol are the lowest and 120-180min after mannitol, ICP have progressly got higher and even higher than before mannitol. ( P<0.01 )The effects of decreasing ICP caused by low and moderate dosage of mannitol have no significant difference. 15min and 30min after high dosage given, ICP shows significant difference. The MAP seems to have a tendency of becoming lower at first and getting higher afterwards and there are no difference among thrapy groups. Contrast with before mannitol, the plasma osmolarity changes of low dosage after mannitol at 3min and 180min have no difference while at 15min, 30min, 60min and 120min, the difference are significant. ( P<0.01 ) To moderate dosage group, besides at 180min after mannitol showing difference ( P<0.05 ) ,the changes at other time points are significant. ( P<0.01 ) As the high dosage group, except no changes after mannitol at 180min, the other changes are significant. ( P<0.01 )All the therapy groups can increase the plasma osmolarity significantly( P<0.01 ) contrast with the control group. The effects of raising the plasma osmolarity after giving mannitol remain for 180min and the effect is most significant at 15min. Contrast with the low dosage group, the moderate dosage of mannitol shows difference after being given for 15min and the large dosage causes significant difference after 15min and has difference after 30min.Conclusions: The intracerebral hematoma model established by micro-pump injection is very stable and reliable and acute intracranial hypertension is then simulated.Mannitol is effective in decreasing raised ICP and the small dosage (such as 0.25g/Kg·weight) can reach the ideal purposes. To keep the effects and safety of mannitol thrapy, it is necessary to have ICP monitoring.Part II Effect of different dosages of mannitol on renal function in animals of intracranial hypertensionObjective:To study the effect of different do... |
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