The fate of hypertonic saline administered during hemodialysis

The possibility of postdialysis hypernatremia is one reason nephrology nurses do not administer hypertonic saline (HS) to treat hypotension or muscle cramps during the last hour of hemodialysis (HD). A single group time series quasi-experimental design was used to evaluate the effect of 50 mEq of HS given during the last hour of HD on interdialytic weight and serum sodium (PNa) and dialysate sodium (DNa) levels. Ten subjects experiencing hypotension or cramps during the last hour of HD, but not during the final 15 minutes, received 50 mEq of HS. One preinjection PNa and DNa sample was obtained, followed by the collection of 8 PNa and 42 DNa samples during the 5 minutes subsequent to the HS injection. Interdialytic weight was evaluated for differences. The results indicated that a statistically significant, but minor amount of sodium was removed in the dialysate (8.77% mEq/L + .96). In addition, the amount of sodium retained over a longer time scale was clinically insignificant, as evidenced by no significant change in the interdialytic weight following administration of 50 mEq of HS. PNa rose 12.7 + 1.3 mEq/L to a peak of 152.2 + 1.6 mEq/l in 54 + 2 seconds, returning to 3 + 0.3 mEq above baseline at 5 minutes. In conclusion, administration of HS up to the final 15 minutes of HD is safe therapy for hypotension and muscle cramps because it does not cause an increased interdialytic weight gain.