ABSTRACT
Background An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection occurred in a medical ward involving patients and hospital staff from May to June 2020. Aim The aim of this study is to determine risk factors related to the outbreak of SARS-CoV-2 in six healthcare workers (HCWs) in a medical ward with initially unrecognized coronavirus disease 2019 (COVID-19) positive patients. Methods A retrospective cross-sectional study was conducted using a comprehensive questionnaire and personal interviews to determine the risk factors for COVID-19 infection in HCWs. Findings A total of 6/34 HCWs were diagnosed with COVID-19 in a medical ward. There were no differences between COVID-19 negative HCWs and COVID-19 positive HCWs in terms of mean duration of hours worked in the unit during the cluster event (180.2 vs 177.5 hours) (p>0.05), mean total time spent in contact with COVID-19 positive patients (12.8 vs 10.5 hours) (p>0.05), mean total time spent on aerosol-generating procedures (1.9 vs 0.9 hours) (p>0.05), and mean total time spent on non-aerosol generating procedures (10.9 vs 9.6 hours ) (p>0.05). There was no difference in exposure to COVID-19 positive family members among the HCWs (33% vs 3.7%, p=0.08). In contrast, exposure to COVID-19 positive contacts in the community was significantly greater in infected vs non-infected HCWs (16.7% vs 0%, p=0.03). Conclusion There was no significant difference in risk factors for contracting SARs-CoV2 among HCWs due to hospital exposures. COVID-19 positive HCWs were more likely to be exposed to positive individuals in their households and community, indicating that the source of SARS-CoV-2 infection came from outside the hospital.
ABSTRACT
NEW FINDINGS: What is the central question of the study? We have previously shown that sinusoidal galvanic vestibular stimulation induces greater modulation of skin sympathetic nerve activity, but not muscle sympathetic nerve activity, in participants who report nausea during simulated motion, but the effects on skin blood flow and blood pressure are unknown. What is the main finding and its importance? During vestibular stimulation, nausea was associated with a greater increase in skin blood flow and a progressive reduction in skin sympathetic nerve activity, but no changes in muscle sympathetic nerve activity. This emphasizes the differential changes in sympathetic outflow to different tissues during nausea. ABSTRACT: We tested the hypothesis that galvanic vestibular stimulation, which produces illusions of side-to-side swaying, causes a greater reduction in skin blood flow in participants who report stimulation-induced nausea. A retrospective analysis was performed on data obtained in 30 participants. Bipolar sinusoidal galvanic vestibular stimulation (sGVS) was applied across the mastoid processes (±2 mA, 0.08 Hz) for 21 min. ECG, continuous blood pressure, respiration and skin blood flow were recorded. Muscle sympathetic nerve activity was recorded in 17 participants and skin sympathetic nerve activity in 12. Ten participants reported motion sickness, whereas 20 did not. Both groups showed an initial reduction in skin (finger) blood flow during sGVS, followed by a sustained increase and a subsequent return towards baseline levels throughout the stimulation; the increase was greater in those who experienced nausea. The increase fits with the progressive reduction in skin sympathetic nerve activity observed in the nauseous group. Mean blood pressure was significantly lower in those who experienced nausea and showed a much larger increase at the onset of sGVS, compared with those who did not. Moreover, the respiratory rate was higher at the outset for the subjects who experienced nausea, decreasing progressively during sGVS, whereas respiratory rate remained constant in those who did not experience nausea. Heart rate was more labile in the subjects who experienced nausea, showing a sustained increase towards the end of stimulation. We have shown that several autonomic parameters change during the nausea induced by vestibular stimulation, but a sustained decrease in skin blood flow is not a hallmark of incipient motion sickness.
