To investigate the relationship between N-terminal Pro-B-type natriuretic peptide (NT-proBNP), Intracranial pressure and hyponatremia in severe Patients with isolated traumatic brain injury.

We measured serum NT-proBNP, ICP and serum sodium levels of 38 patients with isolated severe TBI on 2^ed, 12^th, 24^th, 48^th and 72^ed hour after injury, who were admitted in the Department of Emergency and Neurosurgery in our hospital from 2016 March to 2017 August. At the same time, 10 healthy who have a medical examination were served as control group. The samples was dividied into two groups as high ICP Group [ICP>200 mmH₂O (1 mmH₂O=0.0098 kPa), n=24] and normal ICP Group (ICP<200 mmH₂O, n=14) based on mean ICP=200 mmH₂O, except 6 patients died within observation time. All patients were treated under the guidance of the Brain Trauma Foundation, decompressive craniectomy was applied if necessary. The mean NT-ProBNP values of all the observe time point in high ICP Group, normal ICP Group, and Control Group were progressed with Mann-Whitney U test to distinguish if there was statistical difference between groups. The mean NT-ProBNP values of all the observe time point in high ICP Group were analyzed by Mann-Whitney U test to clarify the law of NT-ProBNP with time. The same were completed in normal ICP Group. The relashion ship between NT-ProBNP values and the corresponding ICP values in high ICP Group was analysised by Peaeson regression analysis, if there is correlation, seeking regression equation, so was in normal ICP Group.

(1) The level of NT-ProBNP in high ICP Group was significantly high than it in normal ICP Group, P<0.05; (2) In the high ICP Group, the level of NT-ProBNP shown two incresed peak respectively at 12^ed and 24^th hour, P<0.05, and kept to 48^th hour, then begun to decrease at 72^ed hour, P<0.05; (3) The relationship between NT-ProBNP and ICP is positive linear correlation, r=0.384, P<0.05,regression equation ICP=0.043NT-ProBNP+258.461; (4) Compered with Control group, NT-ProBNP in the normal ICP Group was only slightly increased, P<0.05; (5) Only one patient showed hyponatremia in normal ICP Group, and got improvement after symptomatic treatment, NT-ProBNP was not associated with hydrological disorder after severe craniocerebral injury.

Not all the rose of NT-ProBNP in severe TBI is significanct, however, the level of NT-ProBNP in high ICP Group is positive linear correlated with intracranial pressure and the level of ICP can be got indirected reflection through it. This study does not get the conclusion that NT-ProBNP can be difined as a blood marker to predicted hyponatremia and distinguish CSWS from SIADH.