Plasma Concentrations Of Atrial Natriuretic Peptide After Subarachnoid Hemorrhage And Its Relationship With Hyponatremia

Purpose: To investigate the role and clinical significance of plasma atrial natriuretic peptide (ANP) in hyponatremia following subarachnoid hemorrhage (SAH) , we observed the plasma concentrations of ANP after SAH and its relationship with hyponatremia following SAH dynamically . Method: The concentrations of plasma ANP and serum sodium were measured by radioimmunoassay in 26 patients at 0 to 3 days , 7 to 9 days and 14 to 16 days after SAH . We divided 26 patients into hyponatremic group (12 patients) and normonatremic group (14 patients) according to the serum sodium concentrations . At the same time , the plasma ANP concentrations were measured by radioimmunoassay in 15 health people as control. We compared the plasma ANP concentrations among hyponatremic group , normonatremic group , control group and analysed the relationship between the plasma ANP concentrations and serum sodium concentrations in hyponatremic group . Result:(1) The serum sodium concentrations of hyponatremic group at 0 to 3 days , 7 to 9 days and 14 to 16 days after SAH were 128. 8 ?6. 2mmol/L, 132. 1 ?3. 6mmol/L, 133. 4 ?3. 2mmol/L; the serum sodium concentrations of normonatremic group at 0 to 3 days , 7 to 9 days and 14 to 16 days after SAH were 139. 2?. 9ramol/L, 138. 9 ?1. 4mmol/L, 139. 3 + 1. 7mmol/L .(2) The plasma ANP concentrations of hyponatremic group at 0 to 3 days , 7 to 9 days and 14 to 16 days after SAH were much higher than those of control group (PO.01) ,the plasma ANP concentrations of hyponatremic group at 7 to 9 days and 14 to 16 days after SAH were higher than those of normonatremic group (7 to 9 days , PO.05 ; 14 to 16 days , P<0.01).(3) The plasma ANP concentrations of normonatremic group at 0 to 3 days and 7 to 9 days after SAH were much higher than those of control group (P<0.01) , while there was no significant differences of the plasma ANP concentrations between normonatremic group at 14 to 16 days after SAH and control group (P>0.05).(4) There were negative correlations between the plasma ANP concentrations and the serum sodium concentrations in hyponatremic group at 0 to 3 days , 7 to 9 days and 14 to 16 days after SAH (0 to 3 days , r=-0.808, P<0.01; 7to9days, r=-0.865, P<0.01; 14to 16 days, r=-0.792, P<0.01) .Conclusion:(1) The plasma ANP concentrations increase markedly at 0 to 3 days after SAH and decrease to normal levels in normonatremic group at two weeks after SAH , while the plasma ANP concentrations remain high in hyponatremic group .These results suggest that the plasma ANP may participate in the occurrence of hyponatremia following SAH , the etiology of hyponatremia following SAH may be attributed to cerebral salt wasting syndrome (CSWS).(2) There were negative correlations between the plasma ANP concentrations and the serum sodium concentrations in hyponatremic group . These results indicate that if a patient had high level of plasma ANP after SAH , we should pay attention to the occurrence and deterioration of hyponatremia.