Hygienic Assessment of Risks of Thermal Balance Disruption in Medical Laboratory Workers Using Personal Protective Equipment for Biohazards

Introduction: Specifics of activities of medical personnel in different types of laboratories can potentially create working conditions that violate occupational safety and health regulations. Objective: The study aimed to assess health risks of thermal balance disruption in PCR laboratory staff wearing personal protective equipment for biohazards in the context of the COVID-19 pandemic. Materials and methods: The study was conducted in winter 2020–2021 in PCR laboratories of the Volgograd Region. It included measurements of laboratory microclimate parameters, such as relative humidity, air temperature and velocity, used to estimate the heat load index. An observation cohort of 31 female medical laboratory workers aged 32.48 ± 1.45 years with a three to nine months experience of work in the PCR laboratory was formed to monitor the thermal state at the start and end of the work shift by measuring skin temperature at five points, sublingual temperature, and heat sensation. The results of measurements were used to estimate the mean skin temperature and heart rate while the dynamics of work ability was assessed by the results of contact tremorometry. Results: We established a significant increase in all measured values. The mean skin temperature at the end of the shift reached 33.85 ± 0.24 °C, thus exceeding the upper limit of the permissible value. The heart rate and heat sensation parameters approached the upper values of the maximum permissible thermal state of a person. Contact tremorometry results indicated a decrease in the performance by the end of the work shift. The findings gave evidence of tension of thermoregulatory reactions and the risk of thermal balance disruption posed by the use of a specific type of personal protective equipment in the PCR laboratory. Conclusion: The research results provide strong support for the conclusion that the use of PPE for biohazards poses a risk of thermal balance disruption in medical laboratory personnel. The severity of stress of thermoregulatory reactions depends on technical and design characteristics of the PPE used. The necessity of a physiological and hygienic substantiation of acceptable duration of work of medical workers wearing various types of PPE for biohazards in PCR laboratories justifies the importance of further studies.

The Possible Interaction of Harderian Material and Saliva for Thermoregulation in the Mongolian Gerbil, Meriones Unguiculatus

Self-grooming in Meriones unguiculatus is associated with saliva spread and the release and spread of Harderian material from the external nares. Saliva spread results in evaporative cooling and Harderian spread insulates the pelage. Two experiments tested the predictions that (1) saliva production and Harderian material decrease systematically following a self-groom, (2) high ambient temperature (34°C) increases saliva production but decreases Harderian release, and (3) low ambient temperature (7°C) decreases saliva production but increases Harderian release. The predictions were generally confirmed, suggesting that short-term and long-term thermoregulatory reactions are differentially affected by ambient temperatures. Thus, an animal will tend to emphasize saliva production when evaporative cooling is needed and will exaggerate Harderian release when insulation of the pelage is required.

Physical fitness and thermoregulatory reactions in a cold environment in men

The relationship between the physical fitness level (maximal O2 consumption, VO2max) and thermoregulatory reactions was studied in 17 adult males submitted to an acute cold exposure. Standard cold tests were performed in nude subjects, lying for 2 h in a climatic chamber at three ambient air temperatures (10, 5, and 1 degrees C). The level of physical fitness conditioned the intensity of thermoregulatory reactions to cold. For all subjects, there was a direct relationship between physical fitness and 1) metabolic heat production, 2) level of mean skin temperature (Tsk), 3) level of skin conductance, and 4) level of Tsk at the onset of shivering. The predominance of thermogenic or insulative reactions depended on the intensity of the cold stress: insulative reactions were preferential at 10 degrees C, or even at 5 degrees C, whereas colder ambient temperature (1 degree C) triggered metabolic heat production abilities, which were closely related to the subject's physical fitness level. Fit subjects have more efficient thermoregulatory abilities against cold stress than unfit subjects, certainly because of an improved sensitivity of the thermoregulatory system.