Administration of Selective α2‐Adrenergic Receptor Agonist Dexmedetomidine During Spine Surgery is Associated with Reduced Postoperative Increase in Plasma p‐Tau181

Abstract

AbstractBackgroundRecent studies have revealed that biomarkers of neuronal injury and Alzheimer's disease (AD) are increased in patients following major surgery. However, the contribution of specific anesthetic agents, such as inhalational or intravenous, remains unclear. In this study, we evaluated whether patients having a predominantly inhalational anesthetic (GAS) compared to patients having a predominantly intravenous anesthetic (IV) would have differences in plasma p‐tau181 levels from preoperative baseline to 3‐months postoperatively. We also examined whether there were differences in p‐tau181 in patients who were intraoperatively administered dexmedetomidine, a selective α2‐adrenergic receptor agonist with neuroprotective effects.MethodIn this prospective observational study of 70 patients (>= 65 years) having elective inpatient spine surgery under general anesthesia at a single academic center, we compared changes in plasma p‐tau181 levels from preoperative baseline to 3‐months postop in patients who received GAS (n=38) compared to IV (n=32). Plasma p‐tau181 levels were measured using the fully automated immunoassay analyzer (Lumipulse G1200, Fujirebio). T‐tests were used to compare 2 groups and 2‐way ANOVA with Tukey's multiple comparisons test was used for dexmedetomidine analyses.ResultOn average plasma p‐tau181 levels increased in the GAS group (n=38) and decreased in the IV group (n=32, mean ± SD; 0.64 ± 2.46 pg/mL vs. ‐1.06 ± 3.24 pg/mL; p=0.014) at 3‐months postop. This was despite the IV group having increased duration of surgery, blood loss, and hospital length of stay. A greater postop increase in plasma p‐tau181 was observed in patients not administered dexmedetomidine (p=0.002). Patients who were not administered dexmedetomidine had a greater increase in postop plasma p‐tau181 in both the GAS and IV groups (main effect of Dexmedetomidine, p=0.02).ConclusionChanges in plasma p‐tau181 levels from preoperative baseline to 3‐months postop were greater in older surgical patients who had GAS compared to IV maintenance of general anesthesia. Importantly, patients not receiving dexmedetomidine showed a greater increase in plasma p‐tau181 levels regardless of anesthesia type.