The Clustering of Chicago - a Long Term Perspective

The purpose of this research lies in two aspects. The first is to carry out an in-depth comparison of the clustering results obtained from different methods, so as to find the “optimal” clustering method. The second is to conduct cluster analysis of Chicago utilizing the census tracts data from three years 1950, 1980 and 2010, aiming to understand the spatio-temporal transitions of Chicago neighborhoods across the years. This study is both a theoretical investigation and a methodological investigation. The results indicates K-means clustering using principal components proved to be the optimal method in terms of the measures we chose, and the longitudinal change in spatial patterns of Chicago resembled the description of Chicago School theorists, while some brand-new trajectories were also detected

Fixed Point and Asymptotic Analysis of Cellular Neural Networks

We firstly employ the fixed point theory to study the stability of cellular neural networks without delays and with time-varying delays. Some novel and concise sufficient conditions are given to ensure the existence and uniqueness of solution and the asymptotic stability of trivial equilibrium at the same time. Moreover, these conditions are easily checked and do not require the differentiability of delays

Analysis of Postoperative Complications and Risk Factors of Patients with Lung Cancer through Clavien-Dindo Classification

Background and objective Postoperative complications (PCs) are contributing factors to patient mortality following lung resection. In this retrospective study, the Clavien-Dindo classification was used to analyze the current incidence of PCs and identify the risk factors of different grades of PCs. Methods A total of 966 lung cancer patients who underwent lobectomy in our department between June 2013 and December 2014 were retrospectively enrolled. Patients were divided into two groups depending on the occurrence of PCs. The PCs were classified into four grades through the Clavien-Dindo classification, and the related risk factors of different grades were evaluated. Results Approximately 15.0% (145/966) of patients had PC (total incidence: 39.3%, 380/966). Among the 380 cases with PCs, the proportions of Clavien-Dindo grade I, grade II, grade III and grade IV or above complications were 6.8%, 75.3%, 15.0% and 2.9%, respectively. Binary Logistic regressions showed that preoperative forced expiratory volume in one second (FEV1), diffusion capacity for carbon monoxide of the lung (single breath)(DLco SB), and preoperative combined chronic obstructive pulmonary disease were the significant independent factors for PCs. FEV1 in preoperative pulmonary function was the significant risk factor for complications at Clavien-Dindo grade I, grade II, grade III, and above. Conclusion Clavien-Dindo grade II complications are the most common complications within 30 days after lung cancer lobectomy. FEV1 is closely related to the occurrence of PCs and may potentially be one of the practical variables to assess the risk of occurrence of PCs

The Feasibility and Safety of No Placement of Urinary Catheter Following Lung Cancer Surgery: A Retrospective Cohort Study With 2,495 Cases

Objectives The study was aimed to investigate the safety and feasibility of avoiding urinary catheterization after surgery in patients undergoing lung cancer resection. Methods Between 1 January 2014 and 31 December 2017, the patients with primary lung cancer who received lobectomy or segmental resection via video-assisted thoracic surgery (VATS) in our department were screened. Based on whether a urinary catheter was inserted after surgery, patients were divided into urinary catheter (UC) group or non-UC group, and rates of postoperative urinary retention (POUR), urinary catheter re-insertion and urinary tract infection (UTI) were compared. Results There was no difference in International prostate symptom score (p = .268) between the groups, but a higher Sedation-Agitation Scale (SAS) score was found in UC group [4.0 (3.0 4.0) vs. 4.0 (2.0, 4.0); p  4; 17.3%, 317/1,835 vs. 12.9%, 86/660, p = .008). In contrast, a higher rate of POUR was observed in non-UC group (11.2%, 74/660 vs. 7.4%, 136/1,835, p = .003), whereas the rate of UTI was significantly lower in this group (5.8%, 38/660 vs. 8.3%, 153/1,835, p = .033). Multivariable analysis revealed the non-placement of UC as the independent factor for POUR (OR: 1.542, 95%CI: 1.135-2.095, p = .006) and UTI (OR: 0.664, 95%CI: 0.459–0.962, p = .031). Conclusion This retrospective study with large sample of 2,495 patients provided evidence to the hypothesis that avoiding urinary catheterization contributed to decrease in the incidence of UTI and was safe and feasible in patients undergoing lung cancer surgery

Impact and Effect of Preoperative Short-term Pulmonary Rehabilitation Training on Lung Cancer Patients with Mild to Moderate Chronic Obstructive Pulmonary Disease: A Randomized Trial

Background and objective Pulmonary rehabilitation (PR) is proposed as an effective strategy to decrease surgical morbidity. However, appropriate rehabilitation plan, initiation time, and optimal duration of PR remain unclear. Lung cancer patients with chronic obstructive pulmonary disease (COPD) are considered high-risk population for postoperative pulmonary complications (PPCs) because of poor lung fitness and cardiopulmonary endurance. This study aims to assess the impact of a one-week, systematic and highly-intensive rehabilitation on surgical lung cancer patients with mild to moderate COPD. Methods A randomized controlled trial with 48 subjects was conducted (24 patients each for the intervention and groups). The intervention group received seven days of systematic, integrated and highly-intensive PR before surgical treatment, including: pharmacotherapy with atomizing terbutaline, pulmicort and infusion of ambroxol; and physical rehabilitation with respiratory training and endurance training. The control group underwent standard preoperative care. Results For the intervention group, the postoperative length of stay was shorter [(6.17±2.91) d vs (8.08±2.21) d; P=0.013]; likewise for the duration of antibiotics use [(3.61±2.53) d vs (5.36±3.12) d; P=0.032]. No significant difference was found between the groups in total in-hospital cost [(46,455.6±5,080.9) ¥ vs (45,536.0±4,195.8) ¥, P=0.498], medicine cost [(7,760.3±2,366.0) vs (6,993.0±2,022.5), P=0.223], and material cost [(21,155.5±10,512.1) ¥ vs (21,488.8±3,470.6) ¥, P=0.883]. In the intervention group, peak expiratory flow [(268.40±123.94) L/min vs (343.71±123.92) L/min; P<0.001], 6-min walk distance (6-MWD) [(595.42±106.74) m vs (620.90±99.27) m; P=0.004], and energy consumption [(59.93±10.61) kcal vs (61.03±10.47) kcal; P=0.004] were statistically different after the seven-day exercise, compared with those on the first day. Finally, for the intervention group the incidence of PPCs (8.3%, 2/24 vs 20.8%, 5/24, 20.8%; P=0.416) were lower. Conclusion The systematic and highly-intensive pulmonary rehabilitation combining abdominal respiration training, respiratory exercise with incentive spirometry, and aerobic exercise could improve the cardiorespiratory endurance of lung cancer patients with mild to moderate COPD. The proposed program may be a practicable preoperative strategy

Can Perioperative Oscillating Positive Expiratory Pressure Practice Enhance Recovery in Lung Cancer Patients Undergoing Thorascopic Lobectomy?

Background and objective Oscillatory positive expiratory pressure (OPEP) training is a kind of breathing exercise with Acapella. The clinical value of OPEP has been widely discussed in chronic obstructive pulmonary disease, bronchiectasis as well as pulmonary cyst. However, few studies have explored the application of OPEP in surgery lung cancer patients underwent lobectomy. Thus, the aim of this study is to explore the impact of the application of OPEP device (acapella) in lung cancer patients undergoing video-assisted thorascopic surgery (VATS). Methods Sixty-nine patients receiving VATS lobectomy in Department of Thoracic Surgery, West China Hospital, Sichuan University from September 15, 2017 to January 15, 2018 were randomly divided into the acapella group (AG) or the control group (CG). The patients in the AG received oscillating positive expiratory pressure training and the CG underwent standard perioperative treatment. The differences of morbidity, pulmonary function, quality of life were compared between the two groups. Results Thirty-five patients were assigned to the AG and thirty-four patients were assigned to the CG. The incidences of postoperative pulmonary complications (PPCs) and atelectasis (2.9%, 0.0%) in the AG were significantly lower than that in the CG (20.6%, 14.7%)(P=0.03, P=0.03). The duration of total hospital stay and postoperative hospital stay in the AG (10.86±5.64, 5.09±4.55) d were significantly shorter than that in the CG (10.86±5.64, 5.09±4.55) d (P=0.01, P=0.01). The drug cost in the AG (4,413.60±1,772.35) ¥ were significantly lower than that in the CG (6,490.35±3,367.66) ¥ (P=0.01). The patients in the AG had better forced expiratory volume in the first second and peak expiratory flow [(1.50±0.32) L,(252.06±75.27) L/min] compared with the CG [(1.34±0.19) L, (216.94±49.72) L/min] (P=0.03, P=0.03) at discharge. Conclusion The application of OPEP device during the perioperative period was valuable in decreasing PPCs and enhancing recovery for lung cancer patients receiving VATS lobectomy

Preoperatiove Airway Bacterial Colonization: the Missing Link between Non-small Cell Lung Cancer Following Lobectomy and Postoperative Pneumonia?

Background and objective Surgical procedure is the main method of treating lung cancer. Meanwhile, postoperative pneumonia (POP) is the major cause of perioperative mortality in lung cancer surgery. The preoperative pathogenic airway bacterial colonization is an independent risk factor causing postoperative pulmonary complications (PPC). This cross-sectional study aimed to explore the relationship between preoperative pathogenic airway bacterial colonization and POP in lung cancer and to identify the high-risk factors of preoperative pathogenic airway bacterial colonization. Methods A total of 125 patients with non-small cell lung cancer (NSCLC) underwent thoracic surgery in six hospitals of Chengdu between May 2015 and January 2016. Preoperative pathogenic airway bacterial colonization was detected in all patients via fiber bronchoscopy. Patients’ PPC, high-risk factors, clinical characteristics, and the serum surfactant protein D (SP-D) level were also analyzed. Results The incidence of preoperative pathogenic airway bacterial colonization among NSCLC patients was 15.2% (19/125). Up to 22 strains were identified in the colonization positive group, with Gram-negative bacteria being dominant (86.36%, 19/22). High-risk factors of pathogenic airway bacterial colonization were age (≥75 yr) and smoking index (≥400 cigarettes/year). PPC incidence was significantly higher in the colonization-positive group (42.11%, 8/19) than that in the colonization-negative group (16.04%, 17/106)(P=0.021). POP incidence was significantly higher in the colonization-positive group (26.32%, 5/19) than that in the colonization-negative group (6.60%, 7/106)(P=0.019). The serum SP-D level of patients in the colonization-positive group was remarkably higher than that in the colonization-negative group [(31.25±6.09) vs (28.17±5.23)](P=0.023). The incidence of preoperative pathogenic airway bacterial colonization among NSCLC patients with POP was 41.67% (5/12). This value was 3.4 times higher than that among the patients without POP (OR=3.363, 95%CI: 1.467-7.711). Conclusion An intimate correlation was observed between POP and pathogenic airway bacterial colonization in lung cancer. The high-risk factors of pathogenic airway bacterial colonization were age and smoking index

Estimated intraoperative blood loss correlates with postoperative cardiopulmonary complications and length of stay in patients undergoing video-assisted thoracoscopic lung cancer lobectomy: a retrospective cohort study

Abstract Background The purpose of our study was to estimate the influence of estimated intraoperative blood loss (EIBL) on postoperative cardiopulmonary complications (PCCs) in patients undergoing video-assisted thoracoscopic surgery (VATS) lobectomy for non-small-cell lung cancer (NSCLC). Methods We conducted a single-center retrospective analysis on the clinical data of consecutive patients in our institution between April 2015 and February 2016. Demographic differences between PCC group and non-PCC group were initially assessed. Receiver operating characteristic (ROC) analysis was performed to determine the threshold value of EIBL for the prediction of PCCs. Demographic differences in the PCC rates and length of stay between two groups of patients divided by this cutoff were further evaluated. A multivariable logistic-regression model involving the clinicopathological parameters with P-value< 0.05 was finally established to identify independent risk factors for PCCs. Results A total of 429 patients with operable NSCLC were included and 80 of them developed PCCs (rate = 18.6%). The mean EIBL in PCC group was significantly higher than that in non-PCC group (133.3 ± 191.3 vs. 79.1 ± 107.1 mL; P < 0.001). The ROC analysis showed an EIBL of 100 mL as the threshold value at which the joint sensitivity (50.0%) and specificity (73.4%) was maximal. The PCC rate in patients with EIBL≥100 mL was significantly higher than that in patients with EIBL< 100 mL (30.1 vs. 13.5%; P < 0.001). Both the length of stay and chest tube duration were significantly prolonged in the patients with EIBL≥100 mL. Finally, EIBL≥100 mL was identified to be predictive of PCCs by multivariable logistic-regression analysis (odds ratio = 3.01; 95% confidence interval = 1.47–6.16; P = 0.003). Conclusions EIBL serves as a significant categorical predictor for cardiopulmonary complications following VATS lobectomy for NSCLC. Thoracic surgeons should minimize the EIBL and strive for the ‘bloodless’ goal to optimize surgical outcomes

Classification and Risk-factor Analysis of Postoperative Cardio-pulmonary Complications after Lobectomy in Patients with Stage I Non-small Cell Lung Cancer

Background and objective There are incresing lung cancer patients detected and diagnosed at the intermediate stage when the pre-malignant or early lesions are amenable to resection and cure, owing to the progress of medical technology, the renewal of detection methods, the popularity of medical screening and the improvement of social health consciousness. The aim of this study is to investigate the risk factors of the occurrence of postoperative cardio-pulmonary complications in stage I non-small cell lung cancer (NSCLC) patients, based on routine laboratory tests, basic characteristics, and intraoperative variables in hospital. Methods The 421 patients after lobectomy in patients with stage I NSCLC at the West China Hospital of Sichuan University from January 2012 to December 2013 were included into the study and stratified into complication group and non-complication group, according to whether to occur postoperative cardio-pulmonary complications after lobectomy in 30 days. Results Of them, 64 (15.2%) patients were finally identified and selected into the complication group, compared with 357 (84.8%) in non-complication group: pneumonia (8.8%, 37/421) was the primary complication, and other main complications included atelectasis (5.9%, 25/421), pleural effusion (≥middle) (5.0%, 21/421), persistent air leak (3.6%, 15/421); The operation time (P=0.007), amount of blood loss (P=0.034), preoperative chronic obstructive pulmonary disease (COPD) (P=0.027), white blood cell (WBC) count (P<0.001), neutrophil-lymphocyte ratio (NLR) (P<0.001) were significantly different between the two groups. According to the binary logistics regression analysis, preoperative COPD (OR=0.031, 95%CI: 0.012-0.078, P<0.001) and WBC count (OR=1.451, 95%CI: 1.212-1.736, P<0.001) were independent risk factors for postoperative cardio-pulmonary complications. Conclusion Among an array of clinical variables in hospital, operation time, preoperative white blood cell count, preoperative COPD, may be the independent risk factors of the occurrence of postoperative cardio-pulmonary complications