Association Between the Rate of Intraoperative Crystalloid Infusion and Postoperative Outcomes in Older Patients Undergoing Spinal Surgery: A Retrospective Cohort Study

As old age affects postoperative outcomes, intraoperative management of geriatric patients should be well established. However, little evidence is available for optimization of fluid therapy during surgery in older patients. To identify the effects of intraoperative fluid management on postoperative complications and one-year morbidity among older patients undergoing spinal surgery. Retrospective cohort study. We included patients aged 70 years or older who underwent spine surgery at the Department of Spine and Neurosurgery of our institution from January 2020 to December 2021 and were followed for one year (up to December 2022). The outcome measures were postoperative in-hospital complications and one-year morbidity. The study sample was divided into three groups according to the rate of intraoperative crystalloid infusion: <4&#xa0;mL/kg/h (restrictive), 4 to 8&#xa0;mL/kg/h (moderate), and >8&#xa0;mL/kg/h (liberal). Logistic regression analysis was conducted to investigate the association between perioperative factors and outcome measures. We performed a sensitivity test with inverse probability of treatment weighting (IPTW) to adjust for selection bias. Among 1192 patients, 207 (17.4%) experienced postoperative in-hospital complications, and 359 (30.1%) developed morbidities within one year of surgery. Upon multivariable logistic regression with IPTW analysis, the rate of intraoperative crystalloid infusion remained a risk factor for postoperative in-hospital complications [liberal group: odds ratio (OR): 2.981, 95% CI: 1.621-5.481, P <0.01, vs. restrictive group] and one-year morbidity (moderate group-OR: 1.622, 95% CI: 1.049-2.510, P =0.030; liberal group-OR: 2.107, 95% CI: 1.336-3.323, P =0.001, vs. restrictive group). Liberal fluid therapy was associated with a higher risk of postoperative in-hospital complications and one-year morbidity compared with restrictive fluid therapy in patients aged 70 years or older who underwent spinal surgery. Further studies are necessary to verify our findings for the establishment of appropriate intraoperative fluid management for geriatric patients.