Time-weighted Average Research Articles

An analytical model for heat transfer characteristics of a deep-buried U-bend pipe and its heat transfer performance under different deflecting angles

This study develops an analytical model for calculating heat transfer characteristics of deep-buried U-bend pipes. The model considers actual thermophysical parameters and a non-uniform ground temperature distribution around the buried pipes. To discuss the analytical model's applicability in both short- and long-term heat transfer operations, the study combines a 72-h field experiment and a 2904-h numerical simulation, verifying the analytical model. The field experiment was conducted on a project comprising deep-buried U-bend pipes at a 2781 m depth in Xi'an and served as a basis for establishing the numerical model. The experimental values and analytical solutions of buried pipes' heat transfer intensity within 72 h are compared, revealing a 10.47 kW time-weighted average of the absolute differences in 8–72 h period. The buried pipes' heat transfer intensity of both the analytical and the numerical solutions was tracked over 2904 h, yielding a 10.58 kW time-weighted average of absolute differences between the analytical and the numerical solutions over a period of 8–2904 h. The established analytical model enables the discussion of the heat transfer performance of U-bend buried pipes at different deflecting angles and promotes providing the design suggestions for deflecting angles in practical engineering.

Abstract 9720: A New Window on a Cerebral Penumbra at Risk for a Secondary Ischemic Brain Injury in Post-Cardiac Arrest Patients

Aim: This study aimed to investigate new target having potential neuroprotective effect against a secondary ischemic brain injury in post out-of-hospital cardiac arrest (OHCA) patients. Methods: This study analyzed physiological variables among OHCA patients with good or poor neurological outcomes despite having normal diffusion-weighted image findings before targeted temperature management (TTM). The factors affecting cerebral perfusion after OHCA, such as the time-weighted average (TWA) of arterial carbon dioxide (PaCO 2 ), oxygen (PaO 2 ), and mean arterial pressure (MAP); and the intracranial pressure (ICP) and quotient albumin ratio (Qalb), measured at 0 and 24 h from the return of spontaneous circulation (ROSC), were analyzed retrospectively using prospectively collected data. The primary outcome was the association between the factors and poor neurological outcome. Results: Fifty-one patients were included in this study. Among them, 11 had poor neurological outcomes. The pre-hospital factors such as anoxic time, initial rhythm; and TWA of physiological factors (PaCO 2 , PaO 2 , and MAP), were not significantly different between groups (p > 0.05). The inter-group comparisons of Qalb at 0 and 24 h were not significant (p > 0.05), whereas Qalb (median [interquartile range]) significantly increased from 0 to 24 h in the poor outcome group (0.007 [0.003 - 0.011] to 0.013 [0.005 - 0.029]; p = 0.04). Simultaneously, the ICP of the poor outcome group significantly increased over time (12.0 mmHg [8.1 - 13.0] to 16.0 mmHg [9.3 - 22.4]; p = 0.03), and higher than those of good outcome group at 24 h (11.0 mmHg [6.5 - 16.0] vs. 16.0 [9.3 - 22.4]; p < 0.01). Conclusion: Blood-brain barrier disruption and increasing ICP were apparent in OHCA patients who progressed into poor outcome despite no significant difference of brain injury before TTM compared with those of good outcome. These factors may be the key window on strategy to prevent the secondary ischemic brain injury after OHCA.

Occupational Exposure to Formaldehyde and Cancer Risk Assessment in an Anatomy Laboratory.

Dissecting a human cadaver is an irreplaceable practice in general training of medical students. Cadavers in anatomy laboratories are usually preserved in formalin, an embalming fluid whose basic component is formaldehyde (FA). The aim of this study is to assess the cancer risk of employees and students that are exposed to FA based on the results of three monitoring campaigns, as well as to suggest permanent solutions to the problem of FA exposure based on the results obtained. Three sampling campaigns of formaldehyde concentration in indoor environments were conducted at five different locations at the Anatomy Department of the Faculty of Medicine with the purpose of assessing permanent employees’ and medical faculty first year students’ exposure to FA. Indoor air was continuously sampled during 8 h of laboratory work and analyzed in accordance with the NIOSH Method 3500. Exceeding of the 8 h time-weighted average (8 h TWA) values recommended by Occupational Safety and Health Administration (OSHA) of 0.75 ppm was recorded in 37% of the samples during the three-month monitoring campaign. Cancer risk assessment levels for permanent employees were in the range from 6.43 × 10−3 to 8.77 × 10−4, while the cancer risk assessment levels for students ranged from 8.94 × 10−7 to 1.83 × 10−6. The results of the research show that cancer risk assessment for employees is several thousand times higher than the limit recommended by the EPA (10−6) and point to the importance of reducing exposure to formaldehyde through the reconstruction of the existing ventilation system, continual monitoring, the use of formaldehyde-free products, and plastination of anatomical specimens.

Investigation of occupational hazard of 750 kV extra high voltage substations

Objective: To understand the current status of major occupational hazards in 750 kV extra high voltage (EHV) substations. Methods: In July 2019, through investigating and detecting the sulfur hexafluoride, power frequency electric field and noise occupational hazards of 750 kV EHV substations in substation 1, substation 2, substation 3, substation 4, substation 5, substation 6 and substation 7, the exposure intensity of the sulfur hexafluoride, power frequency electric field and noise intensity that the operators are exposed to during the inspection process were analyzed. Results: The qualified rate of 358 sulfur hexafluoride test results was 100.0% of the seven 750 kV EHV substations. The qualified rate of 8 h time-weighted average of the power frequency electric field of those 750 kV EHV substations contacted by operators was 100.0%. Among the 847 power frequency electric field detection points, the exceeding standard rate of power frequency electric field was 64.3%, and the differences in the power frequency electric field detection exceeding standard rates of different substations and inspection areas were statistically significant (χ2=87.52, 50.86, P<0.01) . The highest exceeding standard rate of power frequency electric field was the circuit breaker inspection area (94.4%, 34/36) . The noise intensity test results of the seven EHV substations were 41.1-79.7 dB (A) , and the qualified rate was 100.0%. Conclusion: The sulfur hexafluoride, power frequency electric field and noise that the operators contacted in 750 kV EHV substations meet the requirements of occupational exposure limits. The inspection areas of main transformers, capacitors, reactors, bus bars and switches have high power frequency electric field radiation, should be select equipment iand give priority to robot inspection, and reasonably adjust the inspection time to reduce the intensity level of substation operators' exposure to power frequency electric field.

Airborne Fumigants and Residual Chemicals in Shipping Containers Arriving in New Zealand.

BackgroundAirborne fumigants and other hazardous chemicals inside unopened shipping containers may pose a risk to workers handling containers.MethodsGrab air samples from 490 sealed containers arriving in New Zealand were analysed for fumigants and other hazardous chemicals. We also collected grab air samples of 46 containers immediately upon opening and measured the total concentration of volatile organic compounds in real-time during ventilation. Additive Mixture Values (AMV) were calculated using the New Zealand Workplace Exposure standard (WES) and ACGIH Threshold Limit Values (TLV) of the 8-h, time-weighted average (TWA) exposure limit. Regression analyses assessed associations with container characteristics.ResultsFumigants were detectable in 11.4% of sealed containers, with ethylene oxide detected most frequently (4.7%), followed by methyl bromide (3.5%). Other chemicals, mainly formaldehyde, were detected more frequently (84.7%). Fumigants and other chemicals exceeded the WES/TLV in 6.7%/7.8%, and 7.8%/20.0% of all containers, respectively. Correspondingly, they more frequently exceeded ‘1’ for the AMV-TLV compared to the AMV-WES (25.7% versus 7.8%). In samples taken upon opening of doors, fumigants were detected in both fumigated and non-fumigated containers, but detection frequencies and exceedances of the WES, TLV, and AMVs were generally higher in fumigated containers. Detection frequencies for other chemicals were similar in fumigated and non-fumigated containers, and only formaldehyde exceeded both the WES and TLV in both container groups. Volatile compounds in container air reduced rapidly during ventilation. Some cargo types (tyres; personal hygiene, beauty and medical products; stone and ceramics; metal and glass; and pet food) and countries of origin (China) were associated with elevated airborne chemical and fumigant concentrations.ConclusionAirborne chemicals in sealed containers frequently exceed exposure limits, both in fumigated and non-fumigated containers, and may contribute to short-term peak exposures of workers unloading or inspecting containers.

Progression of carotid intima-media thickness in patients treated with lipoprotein apheresis: real-world evidence over 12 years

Abstract Background The extent of intervention effects on carotid intima-media thickness (CIMT) can predict the degree of atherosclerotic cardiovascular disease (ASCVD) risk reduction. There is limited evidence of long-term effects of lipoprotein apheresis on the CIMT progression. Purpose We hypothesized that regular lipoprotein apheresis over the course of 10 years may slow down progression of CIMT in patients with severe hypercholesterolemia. Methods This case series describes ten Caucasian patients (mean age 60±9 years, 70% female, 80% statin intolerant) with familial hypercholesterolemia and/or hyperlipoproteinemia(a) treated with lipoprotein apheresis at a single academic center between 2005 and 2020. The mean and maximum diastolic CIMT of the distal 1 cm of the far wall of the right and left common carotid arteries was measured by the same, trained sonographer utilizing an automated border-detection algorithm. Results The median pre-treatment low-density lipoprotein cholesterol (LDL-C) level was 214 mg/dL (95% confidence interval, 145 to 248), lipoprotein(a), 26 mg/dL (15 to 109; 40% with lipoprotein(a) &amp;gt;60 mg/dL). Using the imputed trajectories, period-specific on-treatment time-weighted averages for LDL-C and lipoprotein(a) were 141 mg/dL (IQR, 89 to 152) and 24 mg/dL (IQR, 12 to 119), respectively. The baseline mean CIMT was 850±170μm and maximum CIMT was 1040±220μm across the age range of 46 to 70 years. Over a median duration of 12 years, regular treatment with lipoprotein apheresis resulted in an average reduction in the mean CIMT of −40μm (IQR, −50 to 20) and maximum CIMT −30μm (IQR, −60 to −10). Among tested lipid and lipoprotein fractions in this sample, the follow-up mean CIMT values strongly correlated only with the baseline lipoprotein(a) levels. Median CIMT progression rates were as follows: mean common carotid, −4μm/y (IQR, −9 to 1), mean common carotid, −12μm/3y (IQR, −26 to 4), maximal common carotid, −3μm/y (IQR, −8 to −1). This translated into 70% (7/10) of cases demonstrating composite mean CIMT below their expected chronologic age, gender and race-stratified vascular age. There was a strong direct correlation between the mean CIMT value at the end of the treatment period and the age of treatment initiation. In this cohort of primary and secondary prevention of patients with severe hypercholesterolemia, the overall rate of ASCVD was 37.5 per 1000 person-years while on lipoprotein apheresis. Conclusions Our observation performed in the clinical setting, demonstrated a real-world effectiveness of lipoprotein apheresis. This analysis supports implementation of aggressive lipid-modifying strategies across all ages. Surveillance with CIMT allows for continued monitoring of atherosclerosis progression and increases compliance with the lipid-modifying therapies in the high-risk patients with poor statin tolerance in the clinical setting. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): KUMC

Too Loud: Noise Exposure in Everyday Life is Causing Hearing Loss

Too Loud: Noise Exposure in Everyday Life is Causing Hearing Loss

Depressive Symptoms Imputed Across the Life Course Are Associated with Cognitive Impairment and Cognitive Decline.

Depressive symptoms may increase risk for dementia, but findings are controversial because late-life depression may be a prodromal dementia symptom. Life course data on depression and dementia risk may clarify this association; however, data is limited. To impute adult depressive symptoms trajectories across adult life stages and estimate the association with cognitive impairment and decline. Using a pooled study of 4 prospective cohorts (ages 20-89), we imputed adult life course depressive symptoms trajectories based on Center for Epidemiologic Studies Depression Scale-10 (CESD-10) and calculated time-weighted averages for early adulthood (ages 20-49), mid-life (ages 50-69), and late-life (ages 70-89) for 6,122 older participants. Adjusted pooled logistic and mixed-effects models estimated associations of imputed depressive symptoms with two cognitive outcomes: cognitive impairment defined by established criteria and a composite cognitive score. In separate models, elevated depressive symptoms in each life stage were associated with cognitive outcomes: early adulthood OR for cognitive impairment = 1.59 (95%CI: 1.35,1.87); mid-life OR = 1.94 (95%CI:1.16, 3.26); and late-life OR = 1.77 (95%CI:1.42, 2.21). When adjusted for depressive symptoms in the other life-stages, elevated depressive symptoms in early adulthood (OR = 1.73; 95%CI: 1.42,2.11) and late-life (OR = 1.43; 95%CI: 1.08,1.89) remained associated with cognitive impairment and were also associated with faster rates of cognitive decline (p < 0.05). Imputing depressive symptom trajectories from pooled cohorts may help expand data across the life course. Our findings suggest early adulthood depressive symptoms may be a risk factor for cognitive impairment independent of mid- or late-life depressive symptoms.

Comparative Evaluation of the Polar Organic Chemical Integrative Sampler in Two Types of Validation Systems Simulating Peak Concentration Events.

Polar organic chemical integrative sampler (POCIS) devices have been suggested for measuring time-weighted averages (TWAs) of contaminant concentrations resulting from chemical leak accidents in aquatic environments. However, the response of the POCIS device in the emergency condition in natural water remains unclear. The response of the POCIS device to contaminant fluctuation was investigated using a chamber test with tap water and a channel test with natural water. The fluctuation in the chamber and the channel simulated the condition of river water under a chemical leak scenario (maximum concentration: 1-10 μg L-1 , half-life: 1 day). The target chemicals were neonicotinoid pesticides (dinotefuran, clothianidin, thiamethoxam, imidacloprid, acetamiprid, and thiacloprid) and bisphenol A. The ratio of the POCIS measured value to the TWA values of grab samplings (POCIS/TWA) for the channel test (temperature: 15 °C, flow velocity: 15 cm s-1 ) ranged from 61% (clothianidin) to 133% (thiacloprid). The results indicated that the POCIS device could be effectively used as a monitoring device in an aquatic environment under the chemical leak scenario over a time period of more than14 days. In addition, the POCIS/TWA ratios obtained from the chamber test and the channel test were in the range of 50-150%. Thus, the chamber test could be used to evaluate the POCIS device at a low cost. Environ Toxicol Chem 2021;40:3010-3018. © 2021 SETAC.

Association Between Cumulative Low-Density Lipoprotein Cholesterol Exposure During Young Adulthood and Middle Age and Risk of Cardiovascular Events

Low-density lipoprotein cholesterol (LDL-C) is a major risk factor for cardiovascular disease (CVD). Most observational studies on the association between LDL-C and CVD have focused on LDL-C level at a single time point (usually in middle or older age), and few studies have characterized long-term exposures to LDL-C and their role in CVD risk. To evaluate the associations of cumulative exposure to LDL-C, time-weighted average (TWA) LDL-C, and the LDL-C slope change during young adulthood and middle age with incident CVD later in life. This cohort study analyzed pooled data from 4 prospective cohort studies in the US (Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Framingham Heart Study Offspring Cohort, and Multi-Ethnic Study of Atherosclerosis). Participants were included if they had 2 or more LDL-C measures that were at least 2 years apart between ages 18 and 60 years, with at least 1 of the LDL-C measures occurring during middle age at 40 to 60 years. Data from 1971 to 2017 were collected and analyzed from September 25, 2020, to January 10, 2021. Cumulative exposure to LDL-C, TWA LDL-C, and LDL-C slope from age 18 to 60 years. Incident coronary heart disease (CHD), ischemic stroke, and heart failure (HF). A total of 18 288 participants were included in this study. These participants had a mean (SD) age of 56.4 (3.7) years and consisted of 10 309 women (56.4%). During a median follow-up of 16 years, 1165 CHD, 599 ischemic stroke, and 1145 HF events occurred. In multivariable Cox proportional hazards regression models that adjusted for the most recent LDL-C level measured during middle age and for other CVD risk factors, the hazard ratios for CHD were as follows: 1.57 (95% CI, 1.10-2.23; P for trend = .01) for cumulative LDL-C level, 1.69 (95% CI, 1.23-2.31; P for trend <.001) for TWA LDL-C level, and 0.88 (95% CI, 0.69-1.12; P for trend = .28) for LDL-C slope. No association was found between any of the LDL-C variables and ischemic stroke or HF. This cohort study showed that cumulative LDL-C and TWA LDL-C during young adulthood and middle age were associated with the risk of incident CHD, independent of midlife LDL-C level. These findings suggest that past levels of LDL-C may inform strategies for primary prevention of CHD and that maintaining optimal LDL-C levels at an earlier age may reduce the lifetime risk of developing atherosclerotic CVD.

Integrated passive sampling and fugacity model to characterize fate and removal of organophosphate flame retardants in an anaerobic-anoxic-oxic municipal wastewater treatment system

It is crucial to deeply understand the fate and removal mechanism of various organophosphate flame retardants (PFRs) in specified wastewater treatment processes. However, concentration fluctuation and matrix effect in wastewater challenge quantification of PFR flux for both field observation and model validation. We present measured seasonal distribution profiles of time-weighted average (TWA) concentrations by in situ hydrophobic and polar passive samplers and modeled mass transport and transformation by means of fugacity for 11 PFRs with varied structures in an anaerobic-anoxic-oxic (A-A-O) municipal wastewater treatment system, and provided a systematic approach to characterize fate and removal mechanism of PFRs in major compartments via various treatment processes. We find evidence that PFRs have a unique structural-dependent fate and removal in the A-A-O system. Hydrophilic chlorinated-PFRs present persistent in all major compartments and dominate in effluents with significant variations; alkyl-PFRs are majorly reduced by biodegradation; whereas hydrophobic aryl-PFRs have the highest removal percentage, contributed by both sorption on solids and biotransformation. Sensitive analysis shows the most influential operation parameters on removal efficiency varied among the PFRs with different properties. We also conclude passive sampling can be effectively applied to estimate TWA wastewater concentrations and to validate fugacity model prediction.

A Low-Power Wearable E-Nose System Based on a Capacitive Micromachined Ultrasonic Transducer (CMUT) Array for Indoor VOC Monitoring

Volatile organic compounds (VOCs) are pervasive in the environment and their real-time continuous monitoring can facilitate better understanding of their effects on human health by combining environmental factors with physiological conditions. The scope of wearable sensors for detection of VOCs is evident as the accuracy of the sensor prediction depends on its proximity to the VOC source along with the sensitivity and selectivity of the sensor itself. In this paper, we present a low-power wearable e-nose system based on a capacitive micromachined ultrasonic transducer (CMUT) array. CMUTs offer inherent benefits of excellent mass resolution, easy array fabrication, and integration with electronics, which make them an appropriate choice as a transducer element for gravimetric e-nose systems. A 5-channel CMUT sensor array was chemically functionalized and used for the detection of four volatiles, ethanol, toluene, p-xylene, and styrene. All the channels of the sensor array achieved a resolution below 10 ppm within 0.2–3% of OSHA-PEL time-weighted average (TWA) for each volatile. For each test cycle, the maximum frequency shift, the rate of adsorption, and the rate of desorption were extracted as features. Linear discriminant analysis (LDA) was applied to visualize the discrimination performance of the sensor array. The system performance was characterized using an automated testing system. The presented sensor system can be used for identification of volatiles with suitable pattern-recognition techniques.

Using Real-Time Area VOC Measurements to Estimate Total Hydrocarbons Exposures to Workers Involved in the Deepwater Horizon Oil Spill.

The objective was to present a method that used real-time volatile organic compounds (VOCs) area measurements transformed to daily total hydrocarbons (THC) time-weighted averages (TWAs) to supplement THC personal full-shift measurements collected using passive charcoal badges. A second objective was to develop exposure statistics using these data for workers on vessels piloting remotely operated vehicle (ROV) vessels and other marine vessels (MVs) not at the job title level, but at the vessel level. From hourly vessel averages derived from ~26 million real-time VOC measurements, we estimated full-shift VOC TWAs. Then, we determined the relationship between these TWAs and corresponding full-shift THC personal measurements taken on the same vessel-day. We used this relationship to convert the full-shift VOC measurements to full-shift 'THC' TWA estimates when no personal THC measurements existed on a vessel-day. We then calculated arithmetic means (AMs) and other statistics of THC exposures for each vessel. The VOC-derived estimates substantially supplemented the THC personal measurements, with the number of vessel-days for which we have exposure estimates increasing by ~60%. The estimates of the AMs are some of the highest observed in the GuLF STUDY. As expected, the AMs decreased over time, consistent with our findings on other vessels. Despite the inherent limitations of using real-time area measurements, we were able to develop additional daily observations of personal THC exposures for workers on the ROV vessels and other MVs over time. The estimates likely resulted in more representative estimates of the AMs in the GuLF STUDY. The method used here can be applied in other occupational settings and industries for personal exposure estimation where large amounts of area measurements and more limited numbers of personal measurements are available.

Hemodynamic monitoring with Hypotension Prediction Index versus arterial waveform analysis alone and incidence of perioperative hypotension

Intraoperative hypotension is associated with increased morbidity and mortality. The Hypotension Prediction Index (HPI) is an advancement of the arterial waveform analysis to predict intraoperative hypotension minutes before episodes occur enabling preventive treatments. We tested the hypothesis that the HPI combined with a personalized treatment protocol reduces intraoperative hypotension when compared to arterial waveform analysis alone. We conducted a retrospective analysis of 100 adult consecutive patients undergoing moderate- or high-risk noncardiac surgery with invasive arterial pressure monitoring using either index guidance (HPI) or arterial waveform analysis (FloTrac) depending on availability (FloTrac, n=50; HPI, n=50). A personalized treatment protocol was applied in both groups. The primary endpoint was the incidence and duration of hypotensive events defined as MAP <65mmHg evaluated by time-weighted average of hypotension. In the FloTrac group, 42 patients (84%) experienced a hypotension while in the HPI group 26 patients (52%) were hypotensive (p=0.001). The median (IQR) time-weighted average of hypotension in the FloTrac group was 0.27 (0.42) mmHg versus 0.10 (0.19) mmHg in the HPI group (p=0.001). Finally, the median duration of each hypotensive event (IQR) was 2.75 (2.40) min in the FloTrac group compared to 1.00 (2.06) min in the HPI group (p=0.002). The application of the HPI combined with a personalized treatment protocol can reduce incidence and duration of hypotension when compared to arterial waveform analysis alone. This study therefore provides further evidence of the transition from prediction to actual prevention of hypotension using HPI.

Acute Pain Burden and Opioid Dose Requirements after Cesarean Delivery in Parturients with Preexisting Chronic Back Pain and Migraine.

Introduction Preexisting chronic pain has been reported to be a consistent risk factor for severe acute postoperative pain. However, each specific chronic pain condition has unique pathophysiology, and it is possible that the effect of each condition on postoperative pain is different. Methods This is a retrospective cohort study of pregnant women with preexisting chronic pain conditions (i.e., migraine, chronic back pain, and the combination of migraine + chronic back pain), who underwent cesarean delivery. The effects of the three chronic pain conditions on time-weighted average (TWA) pain score (primary outcome) and opioid dose requirements in morphine milligram equivalents (MME) during postoperative 48 hours were compared. Results The TWA pain score was similar in preexisting migraine and chronic back pain. Chronic back pain was associated with significantly greater opioid dose requirements than migraine (12.92 MME, 95% CI: 0.41 to 25.43, P=0.041). Preoperative opioid use (P < 0.001) was associated with a greater TWA pain score. Preoperative opioid use (P < 0.001), smoking (P=0.004), and lower postoperative ibuprofen dose (P=0.002) were associated with greater opioid dose requirements. Conclusions Findings suggest women with chronic back pain and migraine do not report different postpartum pain intensities; however, women with preexisting chronic back pain required 13 MME greater opioid dose than those with migraine during 48 hours after cesarean delivery.

The “cost” of noise at work: an occupational injustice among low wage workers and communities

BACKGROUND AND AIM: Noise exposure is ubiquitous in the US and has been associated with various health outcomes. Chronic occupational noise exposure of an 8-hour time weighted average (TWA) ≥85 A-weighted decibels (dBA) leads to permanent noise-induced hearing loss, which has major social impacts and may cost $100 billion annually in lost wages alone. It is estimated that tens of millions of workers are exposed to hazardous levels of occupational noise. Understanding potential occupational and environmental injustices in the distribution of occupational noise across communities and worker income groups is important to examine whether those exposed to hazardous levels of occupational noise are also disproportionately burdened populations. METHODS: Publicly available noise measurements from the US noise job exposure matrix (JEM) and wage estimates from the Bureau of Labor Statistics (BLS) Occupational Employment Statistics (OES) were utilized in mixed-effects logistic regression to analyze (1) national-level job-title noise exposure and the odds of earning $39,810 (median national salary), and (2) metropolitan/nonmetropolitan- (M/NM) level population-weighted occupational noise estimates and the odds of a M/NM area earning $36,020 (median M/NM-level salary). RESULTS:A one-dBA increase in the average noise exposure experienced at work is significantly associated with 1.19 (95% CI: 1.03, 1.38) times higher odds of earning $39,810, and 1.21 (95% CI: 1.03, 1.42) higher odds when controlling for total employment count. A one-dBA increase in a M/NM area’s population-weighted occupational noise estimate is significantly associated with 2.46 (95% CI: 1.50, 4.03) higher odds of a M/NM area earning $36,020, and 1.75 (95% CI: 1.06, 2.89) times higher odds when controlling for rural/urban area. CONCLUSIONS:Higher occupational noise exposure is unequally distributed among lower wage-earning jobs and communities. KEYWORDS: Noise, occupational exposures, socio-economic factors, environmental disparities

Serum estimate of benzene, naphthalene and pyrene as measure of occupational exposure to vehicular air pollution

BACKGROUND AND AIM: Exacerbation in respiration tract infections (RTI) and asthma is associated with exposure to vehicular emission in urban environment. Urban occupational exposure to dust and particulate matter has been shown to increase infections inside airway of human epithelial cells and evidence about rising asthma among occupations working on roadsides were reported. METHODS: Hence, we studied 89 workers directly exposed to vehicular emission such as fuel-station attendants, construction workers, traffic police wardens and bus-drivers with an aim to assess RTI and asthma prevalence resulting from inhalation of air containing dust and vehicular pollutants. Unexposed office workers (n=44) were recruited as control cohort. Exposure was characterized as daily work hours and years associated with current profession. RESULTS:Serum benzene, naphthalene and pyrene median concentrations were 4.5, 12.6, and 2.04 μg/L in exposed group and 0.54, 0.77, and 0.14 μg/L in unexposed cohort, respectively. Compared to self-reported dermal contact, the estimated concentrations were higher in fuel-station attendants related to spills of gasoline (p0.05). After adjusting long work hours, 39% of exposures estimates exceeded the benzene threshold limit value for an 8-h time-weighted average of 1.6 mg/m3. Smokers appeared highly vulnerable to naphthalene (r=0.49, p0.01) and pyrene (r=0.38, p0.05) body burden among traffic police wardens and bus-drivers. Results of regression analysis showed asthma highly prevalent in construction workers (R2=0.53) followed by bus-drivers (R2=0.41). Compared to unexposed control group, RTI was found in 67% of the fuel-station attendants. CONCLUSIONS:We conclude that except construction workers, inhalation and frequent skin exposure to naphthalene and pyrene is unavoidable in all occupational groups. Reducing working hours and job rotation coupled with use of protective equipment are suggested as intervention measures to reduce exposure for vehicular air pollution. KEYWORDS: Air pollution; pyrene, benzene, road-side workers; biomonitoring

Evaluation of indoor PM2.5 concentrations in a Native American Community: a pilot study.

Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease. Indoor PM2.5 concentration was evaluated in 26 homes on the Navajo Nation using real-time PM2.5 monitors. Household risk factors and daily activities were evaluated with three metrics of indoor PM2.5: time-weighted average (TWA), 90th percentile of concentration, and daily minutes exceeding 100 μg/m3. A questionnaire and recall sheet were used to record baseline household characteristics and daily activities. The median TWA, 90th percentile, and daily minutes exceeding 100 μg/m3 were 7.9 μg/m3, 14.0 μg/m3, and 17 min, respectively. TWAs tended to be higher in autumn and in houses that used fuel the previous day. Other characteristics associated with elevated PM exposure in all metrics included overcrowded houses, nonmobile houses, and houses with current smokers, pets, and longer cooking time. Some residents of the Navajo Nation have higher risk of exposure to indoor air pollution by Environmental Protection Agency (EPA) standards. Efforts to identify the causes and associations with adverse health effects are needed to ensure that exposure to risks and possible health impacts are mitigated.

Effect of Hypotension Prediction Index-guided intraoperative haemodynamic care on depth and duration of postoperative hypotension: a sub-study of the Hypotension Prediction trial

BackgroundIntraoperative and postoperative hypotension are associated with morbidity and mortality. The Hypotension Prediction (HYPE) trial showed that the Hypotension Prediction Index (HPI) reduced the depth and duration of intraoperative hypotension (IOH), without excess use of intravenous fluid, vasopressor, and/or inotropic therapies. We hypothesised that intraoperative HPI-guided haemodynamic care would reduce the severity of postoperative hypotension in the PACU. MethodsThis was a sub-study of the HYPE study, in which 60 adults undergoing elective noncardiac surgery were allocated randomly to intraoperative HPI-guided or standard haemodynamic care. Blood pressure was measured using a radial intra-arterial catheter, which was connected to a FloTracIQ sensor. Hypotension was defined as MAP <65 mm Hg, and a hypotensive event was defined as MAP <65 mm Hg for at least 1 min. The primary outcome was the time-weighted average (TWA) of postoperative hypotension. Secondary outcomes were absolute incidence, area under threshold for hypotension, and percentage of time spent with MAP <65 mm Hg. ResultsOverall, 54/60 (90%) subjects (age 64 (8) yr; 44% female) completed the protocol, owing to failure of the FloTracIQ device in 6/60 (10%) patients. Intraoperative HPI-guided care was used in 28 subjects; 26 subjects were randomised to the control group. Postoperative hypotension occurred in 37/54 (68%) subjects. HPI-guided care did not reduce the median duration (TWA) of postoperative hypotension (adjusted median difference, vs standard of care: 0.118; 95% confidence interval [CI], 0–0.332; P=0.112). HPI-guidance reduced the percentage of time with MAP <65 mm Hg by 4.9% (adjusted median difference: –4.9; 95% CI, –11.7 to –0.01; P=0.046). ConclusionsIntraoperative HPI-guided haemodynamic care did not reduce the TWA of postoperative hypotension.

Hydrogen Sulphide (H2S) Exposure Hazard Assessment: An Algorithm for Generating Exposure Index Based on Direct Instrument Readings.

ObjectivesIncreased use of small affordable alarm sensors with logging or network capabilities has improved the ability to monitor exposure. The large datasets generated from these monitors calls for development of a computer algorithm to assess these data.MethodsWe examined 88 time series of hydrogen sulphide (H2S) from wastewater works previously used for developing the exposure index. The time series covered 331 h, where 16 h had readings different from zero.ResultsThe developed algorithm reproduced the manual assessed index almost perfectly (linear regression β = 1.02, R2 = 0.97, P < 0.001). Time-weighted average (TWA) values of the 88 time series showed a mean value of 0.04 ppm (range 0.0–0.9). The mean index value was 18 (range 0–337), with a good linear fit (β = 0.002, R2 = 0.93, and P < 0.001). The index gave us a better resolution and basis for risk assessment than the TWA, and managed to combine evaluation of TWA and exceedance of ceiling value in one number.ConclusionsAs long as peaks above ceiling value occur, we find alarm tools with an H2S sensor to be an essential personal protective equipment against H2S. The proposed method has been verified, and it removes some common human errors in graph evaluation. Use of the index is a possible way of quantifying risk level in exposure to H2S in one single number and provides better understanding of the risk of exposure, as it eases the analysis and evaluation of large numbers of time series.