Background Exposure to volatile organic compounds (VOCs) has been observed in both living and working environments. Volatile organic compounds metabolites (VOCMs) in urine can be used to assess the exposure to VOCs and potentially cause adverse effects on human body. Objective To quantitatively evaluate urinary VOCMs and their associations with renal function damage, and further trace the characteristics of potential environmental exposure to provide scientific evidence for effective prevention measures. Methods The study included a total of 6028 samples from four cross-sectional studies in the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2018, with exposure and health outcomes matched. Generalized linear models were employed to assess the associations of urinary VOCMs (urinary creatinine adjusted) with urinary protein levels and estimated glomerular filtration rate (eGFR), with coviriables including gender, age, body mass index, education, smoking, alcohol consumption, exercise frequency, diabetes, and hypertension. Weighted quantile sum (WQS) approach was utilized to analyze the effects of mixed exposure and to rank the contribution of individual VOCMs. The associations between VOCMs and associated living environments and occupational exposure characteristics were further investigated. Results Among the enrolled study participants (n=6028), a total of 11 urinary VOCMs were measured, with 10 metabolites having a positive rate of over 80% (84.59%-99.99%). There were 604 individuals (10.0%) having urinary protein abnormalities and 2831 individuals (47.0%) with eGFR reduced. Through a single and a multiple generalized linear model, 5 VOCMs exhibited statistically significant associations with urinary protein abnormalities and/or reduced eGFR levels (P<0.05): N-acetyl-S-(N-methylaminocarbonyl)-L-cysteine (AMC), N-acetyl-S-(2-carboxyethyl)-L-cysteine (CEM), N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHB), 2-hydroxy-2-phenylacetic acid (MAD), and N-acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (MB3). The WQS index indicated a significantly positive association between VOCMs and urinary protein abnormalities, and DHB contributed the most. The analysis on the potential sources of VOCs exposure showed that those who worked as a private entrepreneur or an employee (vs. government employees), rent houses (vs. owned real estate), had less number of rooms in the residence, fueled cars at self-service gas stations, and inhaled paint fumes in the past 48 h associated with higher VOCMs (P < 0.05) and DHB contributed the most. Conclusion Multiple VOCMs in urine are associated with significantly kidney function injuries. The mixture exposure to VOCMs is significantly associated with higher risks of urinary protein abnormalities. Occupational category, housing ownership, ways to fuel a car, and inhalation of paint odors are closely related with VOCMs levels.

Objective To study the practicability of measurement of abdominal wall tension (AWT) for noninvasive monitoring of intra-abdominal pressure in ICU patients.Methods Patients with indwelling urethral catheter admitted to ICU from April 2011 to March 2013 were enrolled for a prospective study.Exclusion criteria were patients with muscular relaxants,abdominal operation in three months,acute peritonitis,abdominal mass,acute injury of urinary bladder,acute cystitis,neurogenic bladder,intrapelvis hematoma,and pelvic fracture.The AWT (N/mm) and urinary bladder pressure (UBP) (mm Hg) of all patients were measured.Statistical analysis was performed by SPSS 13.0 statistical software.The correlation of AWT and UBP were analyzed using linear regression analysis.The effects of respiration and body position on AWT were analyzed using the Paired-samples t test,and the effects of gender and body mass index (BMI) on basic level of AWT (IAP ＜ 12 mm Hg) were analyzed using the One-way ANOVA.Results A total of 51 patients were recruited in study.A significantly linear correlation between AWT and UBP were observed (R =0.986,P ＜ 0.01),the regression equation was Y =1.369 + 9.57X (P ＜ 0.01).Under the supine-flat positioning,the intra-abdominal pressures at the end of inspiration and the end of expiration were (1.65 ± 0.52) N/mm and (1.45 ± 0.54) N/mm,respectively,and under body straight up 30° supine positioning,the intra-abdominal pressures at the end of inspiration and the end of expiration were (1.25 ± 0.30) N/mm and (1.07 ± 0.35) N/mm,respectively.There were significant differences in intra-abdominal pressure between different respiratory phases and body positions (P ＜ 0.01).Basic levels of AWT in male and female were (1.09 ± 0.29) N/mm and (1.01 ± 0.34) N/mm.The basic levels of AWT in patients with BMI ＜ 18.5,18.5 ≤ BMI ≤25 and BMI ＞ 25 were (0.91 ± 0.30) N/mm,(1.02 ±0.35) N/mm and (1.16 ±0.28) N/mm respectively,but gender and BMI had no significant effects on basic level of AWT (P =0.457 and 0.313,respectively).Conclusions There was a significantly linear correlation between AWT and UBP,and respiratory phase and body position had significant effects on AWT,but gender and BMI had no significant impacts on basic level of AWT.AWT could be served as a simple,easy,and accurate method to monitor the IAP in critical ill patients.