Hyperchloremia and diuresis in children undergoing scoliosis surgery: A retrospective cohort study

Background: Hyperchloremia is frequent in adult surgical patients and is associated with renal dysfunction. Studies in surgical pediatric patients are lacking. Objectives: To identify both the incidence of postoperative hyperchloremia in children undergoing surgery for idiopathic and non-idiopathic scoliosis, and the association of postoperative hyperchloremia with intraoperative fluid management and postoperative diuresis. Methods: The records of 74 children and adolescents who underwent elective scoliosis surgery were retrospectively evaluated. The primary endpoint was the incidence of serum chloride level ≥ 110 mEq/L at the end of surgery and 12 hours postoperatively. Secondary endpoints were the type and volume of administered fluids, 12 hours postoperative diuresis, and the incidence of postoperative oliguria. Results: Hyperchloremia occurred in 55% of the patients at the end of surgery and in 52% 12 hours postoperatively. Hyperchloremic patients received larger intraoperative volume of 0.9% NaCl diluted cell-saver blood and 10% HAES than did normochloremic patients [median (interquartile range) 6.8 (2.5-11.0) ml/kg vs. 0 (0-7.3), P = 0.003 and 10.0 (0-12.8) vs. 4.4 (0-9.8), P = 0.02, respectively]. Additionally, when compared with normochloremic patients, diuresis during the first 12 hours postoperatively was lower in hyperchloremic patients. Postoperative oliguria (urine output < 0.5 ml/kg/hr for 12 hours) was diagnosed in 7 children (9%), of whom 6 were hyperchloremic at the end of surgery. Conclusions: Early postoperative hyperchloremia is common in children undergoing scoliosis repair surgery and may be attributed to the administration of 0.9% NaCl diluted cellsaver blood and 10% HAES. Postoperative hyperchloremia might be associated with postoperative oliguria.