Field investigation of the heat stress in outdoor of healthcare workers wearing personal protective equipment in South China.

Since the advent of coronavirus disease 2019 (COVID-19), healthcare workers (HCWs) wearing personal protective equipment (PPE) has become a common phenomenon. COVID-19 outbreaks overlap with heat waves, and healthcare workers must unfortunately wear PPE during hot weather and experience excessive heat stress. Healthcare workers are at risk of developing heat-related health problems during hot periods in South China. The investigation of thermal response to heat stress among HCWs when they do not wear PPE and when they finish work wearing PPE, and the impact of PPE use on HCWs' physical health were conducted. The field survey were conducted in Guangzhou, including 11 districts. In this survey, HCWs were invited to answer a questionnaire about their heat perception in the thermal environment around them. Most HCWs experienced discomfort in their back, head, face, etc., and nearly 80% of HCWs experienced "profuse sweating." Up to 96.81% of HCWs felt "hot" or "very hot." The air temperature had a significant impact on thermal comfort. Healthcare workers' whole thermal sensation and local thermal sensation were increased significantly by wearing PPE and their thermal sensation vote (TSV) tended towards "very hot." The adaptive ability of the healthcare workers would decreased while wearing PPE. In addition, the accept range of the air temperature (T a) were determined in this investigation. Graphical Abstract.

Knowledge regarding heat stress and practice of personal protective equipment use among healthcare workers during the COVID 19 pandemic

Introduction: The need for healthcare workers (HCWs) to wear personal protective equipment (PPE) during the coronavirus disease 2019 (COVID-19) pandemic heightens their risk of thermal stress. Objective(s): To determine knowledge regarding heat stress and practice of PPE among HCWs during the COVID-19 pandemic. Material(s) and Method(s): A cross-sectional observational study was done among 115 HCWs using a self-designed questionnaire to identify their thoughts on heat stress caused by PPE wear during the COVID-19 pandemic. The ambient temperature, relative humidity (RH), and dew point in their respective locations were recorded using data loggers (EL-USB-2-LCD+, Lascar Electronics, Salisbury, UK). R version 3.6.2 was used to examine the frequency and descriptive statistics from the survey findings. Pearson's chi-square was used to determine associations. A p value of <0.05 was considered statistically significant. Result(s): The average wet bulb globe temperature (WBG) reported was 30.0oC (IQR 29.1-31.8oC) according to the heat exposure data. The majority of the 115 HCWs were involved in medical consulting (39%), followed by nursing (29%). The researchers discovered that 50% of the workers (n=57) were wearing 5-6 PPEs and had a fourteen-fold increased risk of developing an undesirable thermal health symptom (95 % CI: 0.77 to 280.24;p=0.0737). In addition, 36% of the participants (n=42) worked between 8 and 10 hours every shift with little or no rest. It was also important to note that 76% (n=88) of them worked in non-air-conditioned environments, and 33% (n=38) of them had excessive workloads, which could add to the employees' heat burden. More than half of them agreed that wearing PPE is extremely inconvenient, and they avoided taking breaks to maintain infection control. The impression of thermal stress was reported by 96% of the participants (n=111), and it was found to be substantially linked with the job they were engaged [OR 0.0654 (95% CI: 0.003- 1.246) P=0.001]. More than half of the participants strongly agreed that appropriate rest and hydration before work could help them lower their thermal stress. Conclusion(s): HCWs are cognizant of the effects of heat stress but might not adopt best practices due to various constraints. Ice slurry ingestion could be a practical and effective method for promoting thermal comfort. Adverse effects of heat stress on productivity and judgment of HCWs warrant further investigation.

Czochralski (CZ) process modification with cooling tube in the response to market Global silicon shortage

Recently, the silicon wafer producers, affected by Covid-19 and USA-China competition, looks for new production processes to increase the production. On the other hand, the common parts of CZ puller such as heater, crucible and thermal shield are optimized over time and now the common CZ process is reached to limitation for further improvement. Here, we propose a modified CZ method by adding a cooling tube into the growth zone. The new proposed Cz method is applied to the 8″ crystal growth process. A fully 3D transition model including energy equation, Navier–Stokes equation, surface-to-surface radiation heat transfer, moving mesh and thermal stress equations is implemented. The simulation is performed for both original and new CZ method. It was proved that the new CZ method increases the pulling speed up to 25 %. To ensure about the crystal quality, the thermal stress is compared between original and new proposed CZ method. Although it was found that the thermal stress increases about twice but still the maximum von Mises stress never exceeds the critical value 25 MPa. Additionally, the power consumption is also found to enhance maximum 2 kW under new conditions. To evaluate the model the interface and heater power for the original CZ puller is compared with industrial CZ process and it shows acceptable accuracy. © 2023 Elsevier B.V.

Human thermal physiological response of wearing personal protective equipment: An educational building semi-open space experimental investigation.

With the outbreak and spread of the COVID-19 epidemic, HCWs are frequently required to wear personal protective equipment (PPE) for nucleic acid sample collection in semi-open transition spaces. Wearing PPE causes significant psychological and physical stress in HCWs. In this study, operative temperature (Top) and wet-bulb globe temperature (WBGT) were used to assess thermal conditions through field experiments, while multiple physiological parameters were measured in the subjects. The results indicated that the subjects showed statistically significant differences in thermal perception and physiological parameters with and without PPE. Using observed increases in heart rate (HR), auditory canal temperature (Tac), mean skin temperature (MST), and end-tidal CO2 pressure, subjects were shown to have an increased metabolic rate and heat storage while wearing PPE. Additionally, a decrease in oxygen concentration was also observed, and this decrease may be linked to fatigue and cognitive impairment. Moreover, HR, MST, and Tac showed a significant linear relationship, which increased with temperature and operative temperature, and the HR response was stronger with PPE than without PPE. The neutral, preferred, and acceptable temperatures were significantly lower with PPE than without PPE, and the deviations for neutral Top/WBGT were 9.5/7.1 °C and preferred Top/WBGT was 2.2/4.0 °C, respectively. Moreover, the upper limits of acceptable WBGT, 29.4 °C with PPE and 20.4 °C without PPE, differed significantly between the two phases. Furthermore, the recorded physiological parameter responses and thermal perception responses of the subjects while wearing PPE indicated that they were at risk of thermal stress. Overall, these results suggest that people who wear PPE should focus on their health and thermal stress. This study provides a reference for the development of strategies to counteract heat stress and improve thermal comfort.

The Presence of Opportunistic Premise Plumbing Pathogens in Residential Buildings: A Literature Review

Opportunistic premise plumbing pathogens (OPPP) are microorganisms that are native to the plumbing environment and that present an emerging infectious disease problem. They share characteristics, such as disinfectant resistance, thermal tolerance, and biofilm formation. The colonisation of domestic water systems presents an elevated health risk for immune-compromised individuals who receive healthcare at home. The literature that has identified the previously described OPPPs (Aeromonas spp., Acinetobacter spp., Helicobacter spp., Legionella spp., Methylobacterium spp., Mycobacteria spp., Pseudomonas spp., and Stenotrophomonas spp.) in residential drinking water systems were systematically reviewed. By applying the Preferred reporting items for systematic reviews and meta-analyses guidelines, 214 studies were identified from the Scopus and Web of Science databases, which included 30 clinical case investigations. Tap components and showerheads were the most frequently identified sources of OPPPs. Sixty-four of these studies detected additional clinically relevant pathogens that are not classified as OPPPs in these reservoirs. There was considerable variation in the detection methods, which included traditional culturing and molecular approaches. These identified studies demonstrate that the current drinking water treatment methods are ineffective against many waterborne pathogens. It is critical that, as at-home healthcare services continue to be promoted, we understand the emergent risks that are posed by OPPPs in residential drinking water. Future research is needed in order to provide consistent data on the prevalence of OPPPs in residential water, and on the incidence of waterborne homecare-associated infections. This will enable the identification of the contributing risk factors, and the development of effective controls.

Urban heat island and thermal comfort of Esfahan City (Iran) during COVID-19 lockdown

The Urban Heat Island (UHI), driven in part by urban green space transformation, and resulting in bioclimatic stress, is one of the major environmental problems facing cities today. A brief reprise in UHI severity is hypothesised to have occurred for many cities during COVID-19 lockdown, as a result of the marked reduction in individual and industrial activities. This study explores the UHI the city of Esfahan, one of the major metropolises of Iran, comparing the urban temperature for the period 20 March to 20 April 2020, the first lockdown period in Iran, with a long term mean for this month calculated from 2000-2019. During the lockdown period, the UHI effect covered a much smaller land area than in all prior years investigated. The land surface area which experienced heat stress reduced significantly during the lockdown period, and the total energy heating requirement (heat degree days) increased by 23,945.2 degree day calories compared to the long term average. These results demonstrate the significant changes in UHI and related variables during lockdown. While lockdown regulations are not sustainable in the long run, the improvements recorded demonstrate the potential to mitigate anthropogenic heating.

Dual challenges of heat wave and protective facemask-induced thermal stress in Hong Kong.

During the COVID-19 pandemic, wearing protective facemasks (PFMs) can effectively reduce infection risk, but the use of PFMs can amplify heat-related health risks. We studied the amplified PFM-induced human thermal stress via both field measurements and model simulations over a typical subtropical mountainous city, Hong Kong. First, a hot and humid PFM microenvironment has been observed with high temperature (34-35 °C) and high humidity (80-95%), resulting in an aggravated facial thermal stress with a maximal PFM-covered facial heat flux of 500 W/m2 under high-intensity activities. Second, to predict the overall PFM-inclusive human thermal stress, we developed a new facial thermal load model, S PFM and a new human-environment adaptive thermal stress (HEATS) model by coupling S PFM with an enhanced thermal comfort model to resolve modified human-environment interactions with the intervention of PFM under realistic climatic and topographical conditions. The model was then applied to predict spatiotemporal variations of PFM-inclusive physiological subjective temperature (PST) and corresponding heat stress levels during a typical heat wave event. It was found wearing PFM can significantly aggravate human thermal stress over Hong Kong with a spatially averaged PST increment of 5.0 °C and an additional spatial area of 158.4% exposed to the severest heat risks. Besides, PFM-inclusive PST was found to increase nonlinearly with terrain slopes at a rate of 1.3-3.9 °C/10°(slope), owing to elevated metabolic heat production. Furthermore, urban residents were found to have higher PFM-aggravated heat risks than rural residents, especially at night due to synergistic urban heat and moisture island effects.

Analysis of Physiological Response during Cardiopulmonary Resuscitation with Personal Protective Equipment: A Randomized Crossover Study.

The use of personal protective equipment (PPE) is required for the self-protection of healthcare workers during cardiopulmonary resuscitation (CPR) in patients at risk of aerosol transmission of infectious agents. The aim of this study was to analyze the impact of personal protective equipment on physiological parameters during CPR. A randomized, quasi-experimental, crossover design was used. The study was carried out in a training and simulation emergency box and the total sample consisted of 20 healthcare professionals. Two CPR tests were compared with the recommended sequence of 30 chest compressions and 2 ventilations. The duration of each test was 20 min. One of the CPR tests was carried out without using any PPE (CPR_control), i.e., performed with the usual clothing of each rescuer. The other test was carried out using a CPR test with PPE (i.e., CPR_PPE). The main variables of interest were: CPR quality, compressions, ventilations, maximum heart rate, body fluid loss, body temperature, perceived exertion index, comfort, thermal sensation and sweating. The quality of the CPR was similar in both tests. The maximum heart rate was higher in the active intervals (compressions + bag-valve-mask) of the test with PPE. CPR_PPE meant an increase in the perceived effort, temperature at the start of the thermal sensation test, thermal comfort and sweating, as opposed to CPR performed with usual clothing. Performing prolonged resuscitation with PPE did not influence CPR quality, but caused significant physiological demands. Rescuers were more fatigued, sweated more and their thermal comfort was worse. These results suggest that physical preparation should be taken into account when using PPE and protocols for physiological recovery after use should also be established.

Effects of Face Mask Use on Objective and Subjective Measures of Thermoregulation During Exercise in the Heat.

BACKGROUND: While increased face mask use has helped reduce COVID-19 transmission, there have been concerns about its influence on thermoregulation during exercise in the heat, but consistent, evidence-based recommendations are lacking. HYPOTHESIS: No physiological differences would exist during low-to-moderate exercise intensity in the heat between trials with and without face masks, but perceptual sensations could vary. STUDY DESIGN: Crossover study. LEVEL OF EVIDENCE: Level 2. METHODS: Twelve physically active participants (8 male, 4 female; age = 24 ± 3 years) completed 4 face mask trials and 1 control trial (no mask) in the heat (32.3°C ± 0.04°C; 54.4% ± 0.7% relative humidity [RH]). The protocol was 60 minutes of walking and jogging between 35% and 60% of relative VO2max. Rectal temperature (Trec), heart rate (HR), temperature and humidity inside and outside of the face mask (Tmicro_in, Tmicro_out, RHmicro_in, RHmicro_out) and perceptual variables (rating of perceived exertion (RPE), thermal sensation, thirst sensation, fatigue level, and overall breathing discomfort) were monitored throughout all trials. RESULTS: Mean Trec and HR increased at 30- and 60-minute time points compared with 0-minute time points, but no difference existed between face mask trials and control trials (P > 0.05). Mean Tmicro_in, RHmicro_in, and humidity difference inside and outside of the face mask (ΔRHmicro) were significantly different between face mask trials (P < 0.05). There was no significant difference in perceptual variables between face mask trials and control trials (P > 0.05), except overall breathing discomfort (P < 0.01). Higher RHmicro_in, RPE, and thermal sensation significantly predicted higher overall breathing discomfort (r2 = 0.418; P < 0.01). CONCLUSION: Face mask use during 60 minutes of low-to-moderate exercise intensity in the heat did not significantly affect Trec or HR. Although face mask use may affect overall breathing discomfort due to the changes in the face mask microenvironment, face mask use itself did not cause an increase in whole body thermal stress. CLINICAL RELEVANCE: Face mask use is feasible and safe during exercise in the heat, at low-to-moderate exercise intensities, for physically active, healthy individuals.

Personal protective equipment in the COVID-19 pandemic and the use of cooling-wear as alleviator of thermal stress : A pilot study in plastic surgery staff members.

BACKGROUND: High temperatures at workplaces lead to health-related risks and premature exhaustion. The coronavirus disease 2019 (COVID-19) pandemic requires many health professionals to perform under unfavorable conditions. Personal protective equipment (PPE) causes thermal stress and negatively affects performance. PATIENTS, MATERIALS AND METHODS: This pilot project investigated the effects of PPE and additional cooling wear on physiological parameters and concentration of six healthy staff members of the Plastic Surgery Department of the Medical University of Graz, Austria during simulated patient care. In this study two 1­hour cycles with patient care-related tasks with PPE and PPE + cooling-wear, respectively, were conducted. A third cycle with scrubs exclusively served as baseline/negative control. The assessment occurred immediately pre-cycles and post-cycles. RESULTS: Pre-cycle assessments showed no significant differences between the cycles. After PPE cycle, increased physical stress levels and decrements in concentration capacity were observed. Physiological parameters were significantly less affected in the cooling cycle, while concentration capacity slightly increased. CONCLUSION: COVID-19 PPE causes considerable thermal stress, ultimately affecting human performance. As opportunity to withstand thermal stress, and improve patients' and professionals' safety, cooling-wear can be considered relevant. Medical personnel performing in exceptional situations may particularly benefit from further development and investigation of cooling strategies.

Specifying and Mitigating Thermal Stress Effects on Cognition During Personal Protective Equipment Use.

OBJECTIVE: To report present understanding concerning selected task and environmental factors influencing the changing performance capacity associated with use of personal protective equipment (PPE). BACKGROUND: Much knowledge is available concerning change in complex cognitive capacities under the effects of thermal stress. Our science can inform critical care facilities as to remediation strategies such as work-rest schedules to minimize performance error in highly cognitively demanding circumstances such as intensive care units. METHOD: The present exposition draws from the state-of-the-art understanding concerning thermal stress effects on cognition and workload in complex and demanding tasks. RESULTS: The summation and synthesis of HF/E findings provides important insights into combinatorial effects of forms of stress, typically dealt with only as discrete sources in traditional standards and regulations. The identified interaction between ascending thermal stress and cognitive task demand provides an instance of the plurality of ways HF/E can specify performance limitations in safety-critical circumstances, as witnessed in the current pandemic. CONCLUSION: Accumulated HF/E insights provide systematic ways in which to address and ameliorate the combined forces of physical and cognitive stress on medical personnel constrained to use varying forms of PPE. These principles extend beyond this specific domain to all who are required to work in differential and isolated microclimates. APPLICATION: To minimize the possibility of critical and life-threatening error in intensive care facilities which necessitate PPE use, we need principled work-rest ratio and heat stress mitigation guidance. To promote health, we need to champion healthy work practices in our health workers. HF/E insights can help achieve this important goal.