Ambient air pollution in gastrointestinal endoscopy unit; rationale and design of a prospective study

Indoor CO2 monitoring in a surgical intensive care unit under visitation restrictions during the COVID-19 pandemic

Background

Indoor CO₂ concentration is an important metric of indoor air quality (IAQ). The dynamic temporal pattern of CO₂ levels in intensive care units (ICUs), where healthcare providers experience high cognitive load and occupant numbers are frequently changing, has not been comprehensively characterized.

Objective

We attempted to describe the dynamic change in CO₂ levels in the ICU using an Internet of Things-based (IoT-based) monitoring system. Specifically, given that the COVID-19 pandemic makes hospital visitation restrictions necessary worldwide, this study aimed to appraise the impact of visitation restrictions on CO₂ levels in the ICU.

Methods

Since February 2020, an IoT-based intelligent indoor environment monitoring system has been implemented in a 24-bed university hospital ICU, which is symmetrically divided into areas A and B. One sensor was placed at the workstation of each area for continuous monitoring. The data of CO₂ and other pollutants (e.g., PM2.5) measured under standard and restricted visitation policies during the COVID-19 pandemic were retrieved for analysis. Additionally, the CO₂ levels were compared between workdays and non-working days and between areas A and B.

Results

The median CO₂ level (interquartile range [IQR]) was 616 (524-682) ppm, and only 979 (0.34%) data points obtained in area A during standard visitation were ≥ 1,000 ppm. The CO₂ concentrations were significantly lower during restricted visitation (median [IQR]: 576 [556-596] ppm) than during standard visitation (628 [602-663] ppm; p < 0.001). The PM2.5 concentrations were significantly lower during restricted visitation (median [IQR]: 1 [0-1] μg/m³) than during standard visitation (2 [1-3] μg/m³; p < 0.001). The daily CO₂ and PM2.5 levels were relatively low at night and elevated as the occupant number increased during clinical handover and visitation. The CO₂ concentrations were significantly higher in area A (median [IQR]: 681 [653-712] ppm) than in area B (524 [504-547] ppm; p < 0.001). The CO₂ concentrations were significantly lower on non-working days (median [IQR]: 606 [587-671] ppm) than on workdays (583 [573-600] ppm; p < 0.001).

Conclusion

Our study suggests that visitation restrictions during the COVID-19 pandemic may affect CO₂ levels in the ICU. Implantation of the IoT-based IAQ sensing network system may facilitate the monitoring of indoor CO₂ levels.

Indoor Air Quality in Healthcare Units—A Systematic Literature Review Focusing Recent Research

The adequate assessment and management of indoor air quality in healthcare facilities is of utmost importance for patient safety and occupational health purposes. This study aims to identify the recent trends of research on the topic through a systematic literature review following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology. A total of 171 articles published in the period 2015–2020 were selected and analyzed. Results show that there is a worldwide growing research interest in this subject, dispersed in a wide variety of scientific journals. A textometric analysis using the IRaMuTeQ software revealed four clusters of topics in the sampled articles: physicochemical pollutants, design and management of infrastructures, environmental control measures, and microbiological contamination. The studies focus mainly on hospital facilities, but there is also research interest in primary care centers and dental clinics. The majority of the analyzed articles (85%) report experimental data, with the most frequently measured parameters being related to environmental quality (temperature and relative humidity), microbiological load, CO2 and particulate matter. Non-compliance with the WHO guidelines for indoor air quality is frequently reported. This study provides an overview of the recent literature on this topic, identifying promising lines of research to improve indoor air quality in healthcare facilities.

Ambient air pollution in gastrointestinal endoscopy unit

BACKGROUND

The gastrointestinal endoscopy unit is frequently exposed to gastrointestinal gas expelled from patients and electrocoagulated tissue through carbonation. This can be potentially harmful to the health of not only the healthcare personnel but also patients who undergo endoscopy. This study aimed to measure the air quality in the endoscopy unit.

METHODS

We measured indoor air quality indices (CO₂, total volatile organic compounds (VOCs), PM_2.5, NO₂, CO, and ozone) using portable passive air quality monitoring sensors in the procedural area, recovery area, and cleansing-of-equipment area, at 1-min intervals for 1 week, and the type and number of endoscopic procedures were recorded.

RESULTS

CO₂, PM_2.5, NO₂, and ozone levels were the highest in the cleansing area, followed by the procedural and recovery areas, and VOC level was highest in the procedural area. The proportion of poor-quality level of CO₂ and VOCs was highest in the procedural area and that of NO₂ was highest in the cleansing area. The proportion of tolerable to poor-quality (exceeding acceptable level) level of CO₂ and total VOCs in the procedural area was 26% and 19.2% in all measurement times, respectively. The proportion of tolerable to poor-quality level of NO₂ in the cleansing area of the endoscopy unit was 32.1% in all measurement times. Multivariate analyses revealed that tolerable to poor-quality (exceeding acceptable level) level of VOCs was associated with the number of endoscopic procedures (odds ratio, 1.79; 95% confidence interval, 1.42-2.27) and PM_2.5 level (1.27, 1.12-1.44). Moreover, tolerable to poor-quality level of CO₂ was associated with the number of colonoscopy (5.35, 1.19-24.02), especially with electrocoagulation procedures (24.31, 1.31-452.44) in the procedural area.

CONCLUSIONS

Healthcare personnel and patients who undergo endoscopy are frequently exposed to ambient air pollution. Health-related protective strategies for ambient air pollution in the endoscopy unit are warranted. CLINICALTRIALS.

GOV REGISTRATION NUMBER

NCT03724565.