Monitors to improve indoor air carbon dioxide concentrations in the hospital: A randomized crossover trial.
Sci Total Environ
; 806(Pt 3): 151349, 2022 Feb 01.
Article
in English
| MEDLINE | ID: covidwho-1487964
ABSTRACT
BACKGROUND:
Ventilation has emerged as an important strategy to reduce indoor aerosol transmission of coronavirus disease 2019. Indoor air carbon dioxide (CO2) concentrations are a surrogate measure of respiratory pathogen transmission risk.OBJECTIVES:
To determine whether CO2 monitors are necessary and effective to improve ventilation in hospitals.METHODS:
A randomized, placebo (sham)-controlled, crossover, open label trial. Between February and May 2021, we placed CO2 monitors in twelve double-bed patient rooms across two geriatric wards. Staff were instructed to open windows, increase the air exchange rate and reduce room crowding to maintain indoor air CO2 concentrations ≤800 parts per million (ppm).RESULTS:
CO2 levels increased during morning care and especially in rooms housing couples (rooming-in). The median (interquartile range, IQR) time/day with CO2 concentration > 800 ppm (primary outcome) was 110 min (IQR 47-207) at baseline, 82 min (IQR 12-226.5) during sham periods, 78 min (IQR 20-154) during intervention periods and 140 min (IQR 19.5-612.5) post-intervention. The intervention period only differed significantly from the post-intervention period (P = 0.02), mainly due to an imbalance in rooming-in. Significant but small differences were observed in secondary outcomes of time/day with CO2 concentrations > 1000 ppm and daily peak CO2 concentrations during the intervention vs. baseline and vs. the post-intervention period, but not vs. sham. Staff reported cold discomfort for patients as the main barrier towards increasing ventilation.DISCUSSION:
Indoor air CO2 concentrations in hospital rooms commonly peaked above recommended levels, especially during morning care and rooming-in. There are many possible barriers towards implementing CO2 monitors to improve ventilation in a real-world hospital setting. A paradigm shift in hospital infection control towards adequate ventilation is warranted. TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT04770597.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Air Pollution, Indoor
/
COVID-19
Type of study:
Experimental Studies
/
Prognostic study
/
Randomized controlled trials
Limits:
Aged
/
Humans
Language:
English
Journal:
Sci Total Environ
Year:
2022
Document Type:
Article
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