Relationship between preoperative plasma trimethylamine oxide concentrations and postoperative delirium in elderly patients / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between preoperative plasma trimethylamine oxide (TMAO) concentrations and postoperative delirium (POD) in elderly patients.Methods:One hundred and eighty patients, aged ≥65 yr, of American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, with body mass index of 17-30 kg/m 2, scheduled for elective hip replacement, were enrolled in this study. Venous blood samples were collected at 1 day before surgery, and the plasma TMAO concentrations were measured by high throughput liquid chromatography-tandem mass spectrometry. The patients were divided into 3 groups according to the concentrations of TMAO low-concentration TMAO group (group L, ≤1.2 μmol/L), moderate-concentration TMAO group (group M, 1.3-1.9 μmol/L), and high-concentration TMAO group (group H, ≥2.0 μmol/L). All patients received superior inguinal fascia iliaca compartment block combined with intravenous general anesthesia. POD was identified by the Confusion Assessment Method-Chinese Reversion scale at 1, 2, 3 and 7 days after operation. The patients were divided into POD group and non-POD group according to whether POD occurred. Binary logistic regression analysis was used to evaluate the relationship between different plasma TMAO concentrations and POD. The receiver operating characteristic curve was used to evaluate the efficacy of plasma TMAO concentrations in predicting the occurrence of POD. Results:There were 60 cases in L group, 67 cases in M group and 53 cases in H group, and the incidence of POD was 12%, 22% and 32% in L, M and H groups, respectively. The incidence of POD was significantly higher in group H than in group L ( P<0.05). The plasma TMAO concentration was significantly higher in POD group than in non-POD group ( P<0.05). Logistic regression analysis showed that the risk of POD was 3.91 times higher in group H than in group L ( P<0.05). The area under the receiver operating characteristic curve of preoperative plasma TMAO concentrations in predicting POD was 0.754 (95% confidence interval 0.671-0.838, P<0.05). When the Youden index was 0.426, the optimal cut-off value of plasma TMAO concentrations was 1.625 μmol/L, and the specificity and sensitivity were 0.795 and 0.631, respectively. Conclusions:Elevated preoperative plasma TMAO concentration is associated with an increased risk of POD in elderly patients, and it has a good predictive value for POD.