Correlation between heart rate variability and perioperative neurocognitive disorders in patients undergoing non-cardiac surgery: A retrospective cohort study.

OBJECTIVE: With the improvement of medical level, the number of elderly patients is increasing, and the postoperative outcome of the patients cannot be ignored. However, there have been no studies on the relationship between preoperative heart rate variability (HRV) and Perioperative Neurocognitive Disorders (PND). The purpose of this study was to explore the correlation between (HRV) and (PND), postoperative intensive care unit (ICU), and hospital stay in patients undergoing non-cardiac surgery. METHOD: This retrospective analysis included 687 inpatients who underwent 24-hour dynamic electrocardiogram examination in our six departments from January 2021 to January 2022. Patients were divided into two groups based on heart rate variability (HRV): high and low. Possible risk factors of perioperative outcomes were screened using univariate analysis, and risk factors were included in multivariate logistic regression to screen for independent risk factors. The subgroup analysis was carried out to evaluate the robustness of the results. The nomogram of PND multi-factor logistic prediction model was constructed. The receiver operating characteristic (ROC) curve was drawn, and the calibration curve was drawn by bootstrap resampling 1000 times for internal verification to evaluate the prediction ability of nomogram. RESULT: A total of 687 eligible patients were included. The incidence of low HRV was 36.7% and the incidence of PND was 7.6%. The incidence of PND in the low HRV group was higher than that in the high HRV group (11.8% vs 5.2%), the postoperative ICU transfer rate was higher (15.9% than 9.3%P = 0.009), and the hospital stay was longer [15 (11, 19) vs (13), 0.015]. The multivariable logistic regression analysis showed that after adjusting for other factors, decreased low HRV was identified as an independent risk factor for the occurrence of PND (Adjusted Odds Ratio = 2.095; 95% Confidence Interval: 1.160-3.784; P = 0.014) and postoperative ICU admission (Adjusted Odds Ratio = 1.925; 95% Confidence Interval: 1.128-3.286; P = 0.016). This study drew a nomogram column chart for a multivariate logistic regression model, incorporating age and HRV. The calibration curve shows that the predicted value of the model for the occurrence of cardio-cerebrovascular events is in good agreement with the actual observed value, with C-index of 0.696 (95% CI: 0.626 ~ 0.766). Subgroup analysis showed that low HRV was an independent risk factor for PND in patients with gastrointestinal surgery and ASA Ⅲ, aged ≥ 65 years. CONCLUSION: In patients undergoing non-cardiac surgery, the low HRV was an independent risk factor for PND and postoperative transfer to the ICU, and the hospitalization time of patients with low HRV was prolonged. Through establishing a risk prediction model for the occurrence of PND, high-risk patients can be identified during the perioperative period for early intervention.

Comparison of the femoral condylar ellipse line and the surgical epicondylar axis: 3D measurement by MRI scans in healthy Chinese people.

OBJECTIVE: The sagittal shapes of the femoral condyles were thought to consist of circles. However, the line connecting the centers of circles was not consistent with the surgical epicondylar axis (SEA) which was commonly used in surgery. Recently, ellipses have been proposed as an alternative method to represent the sagittal femoral condylar shape. Does the condylar ellipse line (CEL) coincide with the SEA in 3D MRI reconstruction analysis? METHODS: From May to August 2021, a total of 80 healthy subjects were scanned by MRI on the right knee in this retrospective study. The ellipses on the most distal slices of the medial and lateral condyles were determined. A line connecting the centers of the medial and lateral ellipses was the CEL. A line connecting the deepest point of the medial sulcus and the most prominent point of the lateral epicondyle was the SEA. Angular measurement of the SEA and the CEL relative to the posterior condylar line (PCL) and the distal condylar line (DCL) was performed on an axial and coronal view of the 3D model, respectively. Measurements were compared between males and females by using the independent-samples t-test. Pearson correlation was used to analyze the relationship between SEA-PCL and CEL-PCL, SEA-DCL, and CEL-DCL. RESULTS: On the axial view, the mean SEA-CEL was 0.35° ± 0.96°. SEA-PCL (2.91° ± 1.40°) had a high correlation with CEL-PCL (3.27° ± 1.11°) (r = 0.731, p < 0.001). On the coronal view, the mean coronal SEA-CEL was 1.35° ± 1.13°. SEA-DCL (1.35° ± 1.13°) had a low correlation with CEL-DCL (0.18° ± 0.84°) (r = 0.319, p = 0.007). On the sagittal view, the outlet points of the CEL on the medial and lateral epicondyles were anatomically located in the anteroinferior direction to the SEA. CONCLUSIONS: CEL traversed the medial and lateral epicondyles, which has a mean deviation of 0.35° with SEA on axial view and a mean deviation of 0.18° with DCL on coronal view. This study suggested that the ellipse approach is an improved scheme for representing the femoral condylar shape.

Relationship between Heart Rate Variability and Postoperative Cognitive Dysfunction in Elderly Patients.

Objectives: Postoperative cognitive dysfunction (POCD) is objectively measurable after anesthesia and surgery. Lower heart rate variability (HRV) is associated with poorer cognitive performance, but the relationship between HRV and POCD remains unclear. Methods: Elderly patients who underwent total hip replacement under general anesthesia from the Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University were enrolled. Neuropsychological tests, standard deviation of the interbeat interval (SDNN, a parameter of HRV), and plasma concentrations of glial cell line-derived neurotrophic factors (GDNF) were performed one day before (T-1) and 7 days after (T7) surgery. Results: POCD occurred in 35% of patients on 7 days after surgery. Lower SDNN(T7) (OR=.91) and longer surgery time (OR=1.33) were associated with POCD. Compared with patients without POCD, there was higher variation SDNN (Δ SDNN) and plasma GDNF (ΔGDNF) in those with POCD from T-1 to T7 period. ΔGDNF is positively correlated with ΔSDNN (r = .61, p<.001). Conclusions: Lower SDNN (T7) was associated with POCD and might be used as a warning indicator for the risk of POCD.

Dimensional Changes of Lumbar Intervertebral Foramen in Direct Anterior Approach-Specific Hyperextension Supine Position.

OBJECTIVE: To investigate the changes in the lumbar intervertebral foramen (LIVF) dimensions from neutral supine to direct anterior approach (DAA)-specific hyperextension supine position through a standardized three-dimensional (3D) reconstruction computerized tomography (CT) method. METHODS: A total of 35 healthy volunteers (18 men and 17 women) were included in this retrospective study. The mean age of enrolled subjects was 28.9 ± 5.0 years. In September 2018, all the individuals underwent a 3D CT scan of the lumbar spine in neutral and 30° hyperextension supine positions, which mimicked the patient's position in DAA total hip arthroplasty (THA). The dimensions of the LIVF, including foraminal area, height, and width, were measured on 3D reconstructed CT models at all lumbar foraminal levels. Foraminal area was defined as the area bounded by the adjacent superior and inferior vertebral pedicles, the posterosuperior boundary of the inferior vertebral body, the surface of the intervertebral disc posteriorly, the posteroinferior boundary of the superior vertebral body, and the surface of the ligamentum flavum anteriorly. Foraminal height was defined as the longest distance between the border of the superior and the inferior pedicle. Foraminal width was defined as the shortest distance between the posteroinferior edge of the superior vertebrae and the opposing boundary. Subgroup analysis and multiple linear regression were used to evaluate the relationship between percentage changes of the LIVF dimensions and side, sex, and age. RESULTS: The LIVF dimensions varied significantly between the two positions at all levels (P < 0.05). From neutral to hyperextension supine position, the foraminal area reduced by 20.1% at lumbar 1-2 (L1-2 ), 22.6% at L2-3 , 19.9% at L3-4 , 18.1% at L4-5 , and 12.0% at lumbar 5-sacral 1 (L5 -S1 ) level, respectively; the foraminal height reduced by 9.5% at L1-2 , 10.5% at L2-3 , 9.5% at L3-4 , 9.6% at L4-5 , and 6.1% at L5 -S1 level, respectively; the foraminal width reduced by 12.8% at L1-2 , 14.5% at L2-3 , 13.0% at L3-4 , 10.4% at L4-5 , and 8.4% at L5 -S1 level, respectively. The changes in LIVF dimensions were biggest at L2-3 level and smallest at L5 -S1 level. Subgroup analysis showed that there were no significant differences in the percentage changes of LIVF dimensions between the sexes and sides (P > 0.05). Multiple linear analysis showed that the percentage changes of LIVF dimensions were not related to side, sex, and age (P > 0.05). CONCLUSION: The dimensions of the LIVF showed significant decrease at all levels in the DAA-specific hyperextension supine position compared with the neutral supine position, and the percentage changes of LIVF dimensions were not influenced by side, sex, and age.

Three-point Method to Guide the Tibial Resection and Component Placing in Total Knee Arthroplasty.

OBJECTIVE: To introduce a three-point method combining the midpoint of the posterior cruciate ligament (PCL), the midsulcus of the tibial spines, and the midpoint of the anterior cruciate ligament (ACL) to determine appropriate tibial resection and component placing during TKA and to compare this method with Insall's 1/3 method. METHODS: A consecutive series of 128 knees that underwent TKA from January 2015 to August 2018 were analyzed. In one group (64 knees), the medial 1/3 of tibial tubercle (the Insall's traditional method) was used for tibial component alignment. In the other group (64 knees), the three-point line connecting the midpoint of the PCL, the midpoint of the tibial spines, and the midpoint of the ACL was used for tibial component alignment. Both groups used the anterior tibial tendon as the distal reference for tibial resection. The coronal alignment error of the tibial component was determined by the angle between the line parallel to the tibial component platform and the tibial mechanical axis measured on postoperative radiograph. The axial rotation error of the femoral or tibial component was the intersection angle between the transepicondylar axis (TEA) and a line tangent to the posterior edge of the femoral or tibial component measured on CT. The coronal and axial alignment errors were compared between the two groups. RESULTS: The average coronal alignment error of the tibial component in the three-point method group was 0.2° ± 1.4° versus - 0.9° ± 1.8°in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in the three-point method group reduced by 37.3% compared to Insall's traditional method group. The average axial rotation error of the femoral component was 0.2° ± 1.2° in the three-point method group versus - 1.1° ± 1.7° in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in three-point method group decreased by 43.9% compared to Insall's traditional method group. The average axial rotation error of the tibial component was 0.4° ± 1.4° versus - 1.4° ± 1.8° in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in the three-point method group reduced by 35.5% compared to the Insall's traditional method group. The rates of rotation outliers were significantly lower in the three-point method group (P < 0.05). CONCLUSION: The line connecting the midpoint of the PCL, the midsulcus of the tibial spines, and the midpoint of the ACL could be used as the reference for the tibial resection and component placing. This method appears to be more accurate than Insall's 1/3 method. The results of this study provide a candidate method for component orientation with little error.

Serum glial cell line-derived neurotrophic factor levels and postoperative cognitive dysfunction after surgery for rheumatic heart disease.

OBJECTIVE: Postoperative cognitive dysfunction is an important complication of cardiac surgery with poor outcomes. Serum glial cell line-derived neurotrophic factor levels are decreased in patients with Alzheimer's disease, but the association between glial cell line-derived neurotrophic factor levels and postoperative cognitive dysfunction is poorly understood. The present study aimed to investigate the prognostic value of postoperative serum glial cell line-derived neurotrophic factor levels to predict postoperative cognitive dysfunction in patients with rheumatic heart disease undergoing heart valve replacement. METHODS: This was a prospective observational study of 80 patients undergoing elective heart valve replacement surgery from June 2015 to June 2016 at the Affiliated Hospital of Southeast Medical University. Cognitive functions were assessed 1 day before and 7 days after surgery. Serum glial cell line-derived neurotrophic factor levels were measured by an enzyme-linked immunosorbent assay before (T1) and 1 (T2), 2 (T3), and 7 (T4) days after surgery. Perioperative parameters were evaluated to assess the relationship between glial cell line-derived neurotrophic factors and postoperative cognitive dysfunction. RESULTS: Postoperative cognitive dysfunction was identified in 38 patients (47.5%) 7 days after surgery. Average glial cell line-derived neurotrophic factor levels at 2 and 7 days after surgery in the postoperative cognitive dysfunction group were lower than in the nonpostoperative cognitive dysfunction group at the same time points (P < .001). ΔGlial cell line-derived neurotrophic factor (T1-T3) and Δglial cell line-derived neurotrophic factor (T1-T4) were identified as good predictors of postoperative cognitive dysfunction with threshold for postoperative cognitive dysfunction detection of 49.10 and 60.90, respectively. CONCLUSIONS: The perioperative glial cell line-derived neurotrophic factor levels in patients with postoperative cognitive dysfunction were lower than in patients without postoperative cognitive dysfunction. Glial cell line-derived neurotrophic factor could be an effective predictor for the occurrence of postoperative cognitive dysfunction. The results reveal a potentially important role of decreased glial cell line-derived neurotrophic factor levels in postoperative cognitive dysfunction, with possible treatment targets.