Significant differences were found between the pre - and post-operative levels of serum sodium and hemoglobin in the TURP group ( [ 141.2 + / - 3.5 ] vs [ 136.9 + / - 4.7 ] mmol/L , P < 0.01 ; [ 137.6 + / - 8.8 ] vs [ 124.8 + / - 9.6 ] g/L , P < 0.01 ) , but not in the TUERP group .