Objective:To investigate the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with maintenance hemodialysis (MHD) in Jiangsu province during SARS-CoV-2 pandemic in China from December 7, 2022 to January 27, 2023, and to analyze the influencing factors of all-cause death.Methods:It was a multi-center cross-sectional investigation. Structured questionnaire was used to collect patient information by medical staff of each hemodialysis center (room) as investigators. Part of the demography data and laboratory examination data came from the Jiangsu Province Hemodialysis Data Information System. MHD patients from hemodialysis centers (rooms) at all levels of medical institutions and independent hemodialysis institutions in Jiangsu province during the outbreak of SARS-CoV-2 infection were included, and the clinical characteristics and all-cause mortality of confirmed and suspected cases of SARS-CoV-2 infection were analyzed.Results:Questionnaire surveys and data analysis on 57 278 patients in 407 hemodialysis centers (rooms) were completed, accounting for 90.41% of the total number of MHD patients (63 357 cases) in Jiangsu province during the same period. There were 24 038 cases (41.97%) of SARS-CoV-2 infection and 14 805 cases (25.85%) of suspected infection, which were widely distributed in all dialysis centers in Jiangsu province. After clinical classification of 38 843 confirmed and suspected SARS-CoV-2 infection cases, 3 662 cases were severe and critical cases, accounting for 9.43% of the infected and suspected cases. Among the patients who had completed the questionnaires, there were 1 812 all-cause deaths, with an all-cause mortality rate of 3.16%. Multivariate logistic regression analysis showed that elderly (taking ≤50 years as a reference, 51-59 years: OR=1.583, 95% CI 1.279-1.933, P=0.001; 60-69 years: OR=3.972, 95% CI 3.271-4.858, P<0.001; 70-79 years: OR=7.236, 95% CI 5.917-8.698, P<0.001; ≥80 years: OR=11.738, 95% CI 9.459-14.663, P<0.001), male ( OR=1.371, 95% CI 1.229-1.529, P<0.001), and co-infection with hepatitis B virus (HBV) (positive serum HBV surface antigen, OR=0.629, 95% CI 0.484-0.817, P<0.001) were independent influencing factors for all cause mortality. Receiver-operating characteristic curve analysis showed that the area under the curve for male, age and current HBV infection prediction of all-cause death was 0.529 ( P<0.001), 0.724 ( P<0.001) and 0.514 ( P=0.042), respectively, and the cut-off value for age prediction of all-cause death was 65.5 years old. Compared with patients without HBV infection, MHD patients with HBV infection significantly reduced the proportion of severe and critically ill patients, all-cause hospitalizations and all cause deaths when infected with SARS-CoV-2 (4.99% vs. 6.41%, χ2=6.136, P=0.013; 8.90% vs. 11.44%, χ2=11.662, P<0.001; 2.01% vs. 3.37%, χ2=10.713, P=0.001, respectively). Conclusion:The MHD patients in Jiangsu province are susceptible to SARS-CoV-2. Elderly age and male gender are independent risk factors for death in MHD patients during the epidemic, while the HBV infection may be a protective factor for death of MHD patients infected with SARS-CoV-2.

Objective:To monitor and analyze the divers’ body load during hyperbaric exposure in deep heliox saturation diving at sea, so as to provide reference for safeguarding the safety and health of divers.Methods:The heart rate and rating of perceived exertion (RPE) of the divers were taken to monitor their body loads and the results were analyzed.Results:The heart rates of the four divers were stable. At 6: 30 (63 m) on the third day of decompression, diver 1 had a very low heart rate of 43 beats/min and diver 3 had a heart rate of 53 beats/min. There was no statistically significant difference in the mean heart rates of divers during saturation exposure and each time point of decompression with those before entering the cabin. The overall RPE results of divers ranged from 6 to 16 points, and the overall trend of development was consistent with the pressure change; the highest load was shown in the stage from 100 m stable pressure to the end of excursion diving, while the loads in other stages were relatively small. The mean value of RPE before entering the cabin was slightly higher than that in the pressurized stage, and it reached the peak in the excursion diving stage and then remained stable in the decompression stage. The RPE results of divers in the second diving bell at the end of excursion diving stage were significantly higher than those before entering the cabin ( t=-4.700, P=0.018). Conclusion:It is of important value to guarantee the operation safety by monitoring the divers’ body loads under high pressure. The combination of monitoring heart rate and RPE results can accurately reflect the body load and is conducive to the safety of diving operation.

Objective:To investigate the sleep and stress state of support personnel during deep saturation diving training so as to provide reference for psychological support for such personnel on diving mission.Methods:The Pittsburgh sleep quality index (PSQI) and Stanford acute stress response questionnaire (SASRQ) were used to evaluate 61 sailors from a warship in their annual task of supporting deep saturation diving training.Results:The total score of PSQI was 12.82±3.55, with 57 people higher than 7 points, accounting for 93.44%. There were significant differences in PSQI scores among different age groups, and that of the group aged 20-29 was the highest ( F=3.573, P=0.035). The scores of daytime functional and PSQI of support personnel at different posts were significantly different, and the scores in the posts directly supporting divers are significantly lower than those in the other two kinds of posts ( F=4.945, P=0.010; F=3.806, P=0.029). The average stress level of the crew was 36.87±14.84, among them, 5 sailors were under severe stress, and 16 sailors had more than 3 positive items. Among all the investigated crew members, there was a positive correlation between the stress test score and sleep quality except for the item of "using sleeping aids" . Conclusion:Attention should be paid to the psychological state of support personnel during the whole process of saturation deep diving in order to keep the training safe and smooth.

Objective:To monitor and analyze the divers’ body load during hyperbaric exposure in deep heliox saturation diving at sea, so as to provide reference for safeguarding the safety and health of divers.Methods:The heart rate and rating of perceived exertion (RPE) of the divers were taken to monitor their body loads and the results were analyzed.Results:The heart rates of the four divers were stable. At 6: 30 (63 m) on the third day of decompression, diver 1 had a very low heart rate of 43 beats/min and diver 3 had a heart rate of 53 beats/min. There was no statistically significant difference in the mean heart rates of divers during saturation exposure and each time point of decompression with those before entering the cabin. The overall RPE results of divers ranged from 6 to 16 points, and the overall trend of development was consistent with the pressure change; the highest load was shown in the stage from 100 m stable pressure to the end of excursion diving, while the loads in other stages were relatively small. The mean value of RPE before entering the cabin was slightly higher than that in the pressurized stage, and it reached the peak in the excursion diving stage and then remained stable in the decompression stage. The RPE results of divers in the second diving bell at the end of excursion diving stage were significantly higher than those before entering the cabin ( t=-4.700, P=0.018). Conclusion:It is of important value to guarantee the operation safety by monitoring the divers’ body loads under high pressure. The combination of monitoring heart rate and RPE results can accurately reflect the body load and is conducive to the safety of diving operation.

Objective:To investigate the sleep and stress state of support personnel during deep saturation diving training so as to provide reference for psychological support for such personnel on diving mission.Methods:The Pittsburgh sleep quality index (PSQI) and Stanford acute stress response questionnaire (SASRQ) were used to evaluate 61 sailors from a warship in their annual task of supporting deep saturation diving training.Results:The total score of PSQI was 12.82±3.55, with 57 people higher than 7 points, accounting for 93.44%. There were significant differences in PSQI scores among different age groups, and that of the group aged 20-29 was the highest ( F=3.573, P=0.035). The scores of daytime functional and PSQI of support personnel at different posts were significantly different, and the scores in the posts directly supporting divers are significantly lower than those in the other two kinds of posts ( F=4.945, P=0.010; F=3.806, P=0.029). The average stress level of the crew was 36.87±14.84, among them, 5 sailors were under severe stress, and 16 sailors had more than 3 positive items. Among all the investigated crew members, there was a positive correlation between the stress test score and sleep quality except for the item of "using sleeping aids" . Conclusion:Attention should be paid to the psychological state of support personnel during the whole process of saturation deep diving in order to keep the training safe and smooth.