Affordable measures to monitor and alarm nosocomial SARS-CoV-2 infection due to poor ventilation.
Indoor Air
; 31(6): 1833-1842, 2021 11.
Article
in English
| MEDLINE | ID: covidwho-1285031
ABSTRACT
Since the coronavirus disease 2019 (COVID-19) outbreak, the nosocomial infection rate worldwide has been reported high. It is urgent to figure out an affordable way to monitor and alarm nosocomial infection. Carbon dioxide (CO2 ) concentration can reflect the ventilation performance and crowdedness, so CO2 sensors were placed in Beijing Tsinghua Changgung Hospital's fever clinic and emergency department where the nosocomial infection risk was high. Patients' medical records were extracted to figure out their timelines and whereabouts. Based on these, site-specific CO2 concentration thresholds were calculated by the dilution equation and sites' risk ratios were determined to evaluate ventilation performance. CO2 concentration successfully revealed that the expiratory tracer was poorly diluted in the mechanically ventilated inner spaces, compared to naturally ventilated outer spaces, among all of the monitoring sites that COVID-19 patients visited. Sufficient ventilation, personal protection, and disinfection measures led to no nosocomial infection in this hospital. The actual outdoor airflow rate per person (Qc ) during the COVID-19 patients' presence was estimated for reference using equilibrium analysis. During the stay of single COVID-19 patient wearing a mask, the minimum Qc value was 15-18 L/(s·person). When the patient was given throat swab sampling, the minimum Qc value was 21 L/(s·person). The Qc value reached 36-42 L/(s·person) thanks to window-inducted natural ventilation, when two COVID-19 patients wearing masks shared the same space with other patients or healthcare workers. The CO2 concentration monitoring system proved to be effective in assessing nosocomial infection risk by reflecting real-time dilution of patients' exhalation.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Cross Infection
/
Air Pollution, Indoor
/
COVID-19
Type of study:
Experimental Studies
/
Prognostic study
/
Randomized controlled trials
Limits:
Humans
Language:
English
Journal:
Indoor Air
Journal subject:
Environmental Health
Year:
2021
Document Type:
Article
Affiliation country:
Ina.12899
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