Impact of Personal Protective Equipment on Cardiopulmonary Resuscitation and Rescuer Safety.

Background: High-quality cardiopulmonary resuscitation (CPR) is a key element in the rescue of cardiac arrest patients but is difficult to achieve in circumstances involving aerosol transmission, such as the COVID-19 pandemic. Methods: This prospective randomized crossover trial included 30 experienced health care providers to evaluate the impact of personal protective equipment (PPE) on CPR quality and rescuer safety. Participants were asked to perform continuous CPR for 5 minutes on a manikin with three types of PPE: level D-PPE, level C-PPE, and PAPR. The primary outcome was effective chest compression per minute. Secondary outcomes were the fit factor by PortaCount, vital signs and fatigue scores before and after CPR, and perceptions related to wearing PPE. Repeated-measures ANOVA was used, and a two-tailed test value of 0.05 was considered statistically significant. Results: The rates of effective chest compressions for 5 minutes with level D-PPE, level C-PPE, and PAPRs were 82.0 ± 0.2%, 78.4 ± 0.2%, and 78.0 ± 0.2%, respectively (p = 0.584). The fit-factor test values of level C-PPE and PAPRs were 182.9 ± 39.9 vs. 198.9 ± 9.2 (p < 0.001). The differences in vital signs before and after CPR were not significantly different among the groups. In addition, the fatigue and total perception scores of wearing PPE were significantly higher for level C-PPE than PAPRs: 3.8 ± 1.6 vs. 3.0 ± 1.6 (p < 0.001) and 27.9 ± 5.4 vs. 26.0 ± 5.3 (p < 0.001), respectively. Conclusion: PAPRs are recommended when performing CPR in situations where aerosol transmission is suspected. When PAPRs are in short supply, individual fit-tested N95 masks are an alternative. This trial is registered with NCT04802109.

Estimation of respiratory heat flows in prediction of heat strain among Taiwanese steel workers.

International Organization for Standardization 7933 standard provides evaluation of required sweat rate (RSR) and predicted heat strain (PHS). This study examined and validated the approximations in these models estimating respiratory heat flows (RHFs) via convection (C res) and evaporation (E res) for application to Taiwanese foundry workers. The influence of change in RHF approximation to the validity of heat strain prediction in these models was also evaluated. The metabolic energy consumption and physiological quantities of these workers performing at different workloads under elevated wet-bulb globe temperature (30.3 ± 2.5 °C) were measured on-site and used in the calculation of RHFs and indices of heat strain. As the results show, the RSR model overestimated the C res for Taiwanese workers by approximately 3 % and underestimated the E res by 8 %. The C res approximation in the PHS model closely predicted the convective RHF, while the E res approximation over-predicted by 11 %. Linear regressions provided better fit in C res approximation (R 2 = 0.96) than in E res approximation (R 2 ≤ 0.85) in both models. The predicted C res deviated increasingly from the observed value when the WBGT reached 35 °C. The deviations of RHFs observed for the workers from those predicted using the RSR or PHS models did not significantly alter the heat loss via the skin, as the RHFs were in general of a level less than 5 % of the metabolic heat consumption. Validation of these approximations considering thermo-physiological responses of local workers is necessary for application in scenarios of significant heat exposure.

Prioritizing factors associated with thermal stresses imposed on workers in steel and iron casting industries using the Monte Carlo simulation and sensitivity analysis.

OBJECTIVES: The aims of this study were to develop approaches for monitoring and prioritizing factors associated with thermal stresses imposed on workers in iron and steel casting industries, and to eventually purpose effective control strategies. METHODS: The whole study was completed in the furnace areas of two steel casting and two iron casting plants, where the air temperature (Ta), radiant temperature (Tr), air velocity (Va) and partial water vapor pressure (Pa) were measured continuously during two consecutive work cycles. Simultaneously, the metabolic rates (M) of all workers in the furnace area were also measured. RESULTS: Using the WBGT as an index for screening purposes, our results suggest that all furnace area workers in both types of casting plants might experience severe heat stress. The predicted heat strain (PHS) model proposed by ISO 7933 was further adopted for detailed analysis from the physiological aspect. Through use of the Monte Carlo simulation and sensitivity analysis, both M and Tr were found to be the two most important factors associated with workers' thermal hazard. Therefore, two effective control strategies were suggested, including reducing workloads of workers and reducing radiant heat transmitting from furnaces to workplace environments. CONCLUSIONS: The approach developed in the present study would be beneficial to many other industries for initiating strategies to avert the thermal hazard imposed on workers.

Combined effects of noise, vibration, and low temperature on the physiological parameters of labor employees.

Noise, vibration, and low temperature render specific occupational hazards to labor employees. The purpose of this research was to investigate the combined effects of these three physical hazards on employees' physiological parameters. The Taguchi experimental method was used to simulate different exposure conditions caused by noise, vibration, and low temperature, and their effects on the physiological parameters of the test takers were measured. The data were then analyzed using statistical methods to evaluate the combined effects of these three factors on human health. Results showed that the factor that influenced the finger skin temperature, manual dexterity, and mean artery pressure (MAP) most was air temperature, and exposure time was the second most influential factor. Noise was found to be the major factor responsible for hearing loss; in this case, hand-arm vibration and temperature had no effect at all. During the study, the temperature was confined in the 5-25°C range (which was not sufficient to study the effects at extremely high- and low-temperature working conditions) because the combined effects of even two factors were very complicated. For example, the combined effects of hand-arm vibration and low temperature might lead to occupational hazards such as vibration-induced white finger syndrome in working labors. Further studies concerning the occupational damage caused by the combined effects of hazardous factors need to be conducted in the future.

Developing a semi-quantitative occupational risk prediction model for chemical exposures and its application to a national chemical exposure databank.

In this study, a semi-quantitative occupational chemical exposure risk prediction model, based on the calculation of exposure hazard indexes, was proposed, corrected, and applied to a national chemical exposure databank. The model comprises one factor used to describe toxicity (i.e., the toxicity index), and two factors used to reflect the exposure potential (i.e., the exposure index and protection deficiency index) of workers exposed to chemicals. An expert system was used to correct the above proposed model. By applying the corrected model to data obtained from a national occupational chemical hazard survey program, chemical exposure risks of various manufacturing industries were determined and a national control strategy for the abatement of occupational chemical exposures was proposed. The results of the present study would provide useful information for governmental agencies to allocate their limited resources effectively for reducing chemical exposures of workers.

Effect of low frequency noise on the echocardiographic parameter E/A ratio.

The hearing condition of the Taiwanese aerospace maintenance workers affected by the low frequency noise had not been reported. The purpose of this research is to clarify the maintenance workers' health effect when exposed to low frequency and/or general noises and to understand the relationship between the variations of the worker's echocardiographic E/A ratio and the low frequency noise. The low frequency noise monitoring and echocardiographic E/A ratio results obtained for 213 aerospace maintenance workers indicated that the workers' hearing loss was more serious at high frequency 4k and 6k when exposed to the low frequency noise and could be more than 40 dB. The abnormality of echocardiographic E/A ratio was also higher than that of control group.

Exposure assessment of aluminum arc welding radiation.

The purpose of this study is to evaluate the non-ionizing radiation (NIR) exposure, especially optical radiation levels, and potential health hazard from aluminum arc welding processes based on the American Conference of Governmental Industrial Hygienists (ACGIH) method. The irradiance from the optical radiation emissions can be calculated with various biological effective parameters [i.e., S(lambda), B(lambda), R(lambda)] for NIR hazard assessments. The aluminum arc welding processing scatters bright light with NIR emission including ultraviolet radiation (UVR), visible, and infrared spectra. The UVR effective irradiance (Eeff) has a mean value of 1,100 microW cm at 100 cm distance from the arc spot. The maximum allowance time (tmax) is 2.79 s according to the ACGIH guideline. Blue-light hazard effective irradiance (EBlue) has a mean value of 1840 microW cm (300-700 nm) at 100 cm with a tmax of 5.45 s exposure allowance. Retinal thermal hazard effective calculation shows mean values of 320 mW cm(-2) sr(-1) and 25.4 mW (cm-2) (380-875 nm) for LRetina (spectral radiance) and ERetina (spectral irradiance), respectively. From this study, the NIR measurement from welding optical radiation emissions has been established to evaluate separate types of hazards to the eye and skin simultaneously. The NIR exposure assessment can be applied to other optical emissions from industrial sources. The data from welding assessment strongly suggest employees involved in aluminum welding processing must be fitted with appropriate personal protection devices such as masks and gloves to prevent serious injuries of the skin and eyes upon intense optical exposure.

Evaluation of auditory fatigue in combined noise, heat and workload exposure.

This study was performed in a climatic chamber to evaluate the combined effects of noise intensity, heat stress, workload, and exposure duration on both noise-induced temporary threshold shift (TTS) and the recovery time by adopting Taguch's method. Fourteen subjects without previous significant noise exposure and smoking history were recruited to participate in this study. All hearing threshold levels at eight different frequencies (250 to 8,000 Hz) of better ear were measured in an audiometric booth by using the ascending method in 2 dB steps before each exposure condition. The test was also carried out after exposure to evaluate TTS at various times. The TTS recovery time was assessed using an audiometric test on all subjects at post-exposure times of 2, 20, 40, 60, 80 and 120 min, respectively. It was found that TTS depended mainly on the exposed noise dose and was enhanced by workload and heat stress. The TTS recovery time is dependent upon the magnitude of the initial hearing loss. In conclusion, TTS driven by noise exposure is enhanced by heat and workload. Further studies are required to evaluate the effects of workload with extreme temperature in a workplace environment.

Evaluating the efficacy of a thermal exposure chamber designed for assessing workers' thermal hazard.

This study was conducted on a thermal exposure chamber designed for assessing workers' thermal hazard. In order to assess the efficacy of the studied chamber, three environmental conditions were selected to simulate high, middle and low thermal impact situations, with air temperatures (Ta) of 43.12, 36.23 and 25.77 masculine C, globe temperatures (Tg) of 44.41, 41.07 and 29.24 masculine C, relative humidity (RH) of 77, 59 and 39%, and air flow velocities (Va) of 1.70, 0.91 and 0.25 m/s, respectively. For the three specified thermal impact conditions, results show that the coefficients of variation (CVs) for Ta, Tg, RH and Va measured in the chamber studied were consistently less than 10%, except for Va under the low thermal impact condition (=50%). For each specified thermal impact condition, we generated 1,000 environmental combinations by using the Monte Carlo simulation approach according to the variations obtained from the four environmental factors. We directly adopted the ISO 7933 approach to estimate the allowable exposure time (AET) for each simulated environmental condition. This study yielded a range in the 95% confidence interval (95% CI) of the estimated AETs for the three specified thermal impact conditions which were consistently less than 5 min. We further conducted the sensitivity analysis to examine the effect of the four environmental factors on estimating AETs. We found Va was the least important factor in estimating AETs for any specified thermal impact condition. In conclusion, although Va was found with great variation for the chamber specified in the low thermal impact condition, the exposure chamber studied can still be regarded as a feasible one for assessing workers' thermal hazard.