Serum osmolar and electrolyte changes associated with large infusions of hypertonic sodium lactate for intravascular volume expansion of patients undergoing aortic reconstruction.

To better define the serum osmolar and compositional changes associated with the infusion of a large volume of hypertonic saline solution (sodium of 250 milliequivalents per liter), we compared resuscitation using a hypertonic crystalloid (HSL) to Ringer's lactate (RL) in 52 patients undergoing aortic reconstruction. There were no differences between the groups in any of the preoperative measurements, the duration of operation, operative blood loss or transfusion requirement. The RL group required 9.5 liters of fluid intraoperatively as compared with 6.3 liters required by the HSL group (p less than 0.01). There was no significant difference between the groups in the amount of sodium infused to achieve resuscitation or in the sodium balance at the end of the study period. Hypernatremia (average maximum serum sodium: 157 milliequivalents per liter) and hyperosmolarity (average maximum serum osmolarity: 320 milliosmoles per liter) resolved in the HSL group within 48 hours. Correction of the hyperosmolar state was thought to be due to the judicious administration of free water and a decrease in renal free water clearance. The HSL group required significantly greater potassium administration during the early postoperative period due to increased kaluresis. HSL is safe and effective for use in the resuscitation of moderate blood volume deficit. Changes in serum sodium values and in osmolarity resolve rapidly. The serum potassium level should be monitored closely and replaced aggressively.