Impact of Intraoperative Fluid Management on Electrolyte and Acid-Base Variables During Posterior Spinal Fusion in Adolescents

INTRODUCTION: Various isotonic fluids may be used to maintain intravascular homeostasis during major surgical procedures. Variations in the electrolyte and buffer concentrations between these solutions may result in differential changes in electrolyte and acid-base status during fluid resuscitation. This study evaluates these changes during posterior spinal fusion in adolescents. METHODS: Patients were randomized to receive lactated Ringers (LR), normal saline (NS) or Normosol-R® (NR) during posterior spinal fusion (N=19, 20, and 20, respectively). The specific fluid was used for maintenance fluids as well as fluid replacement of deficits, third space losses, and blood loss. RESULTS: Patients who received NS had a greater base deficit (NS: −2.0 ± 2.2 vs NR −0.6 ± 1.8, p=0.031 or LR: −0.2 ± 1.7, p=0.007) and were more likely to have a ≥2 point change in the base deficit (60% with NS compared to 30% with NR and 47% with LR). Patients receiving NS also had a lower pH (NS: 7.37 ± 0.03 vs NR: 7.39 ± 0.04, p=0.013) and a greater change in pH (NS: −0.03 ± 0.04 vs NR: 0.01 ± 0.06). CONCLUSION: The use of NS for intraoperative resuscitation during posterior spinal fusion in adolescents resulted in a greater base deficit and a lower pH than the use of LR or NR. Although these changes had limited clinical significance in our patient population, future studies are indicated to further investigate the potential clinical impact of these changes.