Particle and bioaerosol characteristics in a paediatric intensive care unit

Congrong He; Ian M Mackay; Kay Ramsay; Zhen Liang; Timothy Kidd; Luke D Knibbs; Graham Johnson; Donna McNeale; Rebecca Stockwell; Mark G Coulthard; Debbie A Long; Tara J Williams; Caroline Duchaine; Natalie Smith; Claire Wainwright; Lidia Morawska

doi:10.1016/j.envint.2017.06.020

Particle and bioaerosol characteristics in a paediatric intensive care unit

Environ Int. 2017 Oct:107:89-99. doi: 10.1016/j.envint.2017.06.020. Epub 2017 Jul 7.

Authors

Affiliations

¹ International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia; Central Analytical Research Facility, Institute for Future Environment, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
² Public and Environmental Health - Virology, Health Support Queensland, Department of Health, Queensland Government, Coopers Plains 4108, Australia; Queensland Paediatric Infectious Diseases (QPID) Laboratory, Centre for Children's Health Research, The University of Queensland, 62 Graham St, South Brisbane, Queensland 4101, Australia; Faculty of Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
³ Academic Discipline of Paediatrics and Child Health, School of Clinical Medicine, The University of Queensland, 501 Stanley St, South Brisbane, Queensland 4101, Australia; QIMR Berghofer Medical Research Institute, Herston, Queensland 4006, Australia.
⁴ International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia; College of Environmental Science & Engineering, Donghua University, Shanghai 201620, China.
⁵ Queensland Paediatric Infectious Diseases (QPID) Laboratory, Centre for Children's Health Research, The University of Queensland, 62 Graham St, South Brisbane, Queensland 4101, Australia.
⁶ School of Public Health, The University of Queensland, Herston, Queensland 4006, Australia.
⁷ International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
⁸ Academic Discipline of Paediatrics and Child Health, School of Clinical Medicine, The University of Queensland, 501 Stanley St, South Brisbane, Queensland 4101, Australia; Paediatric Intensive Care Unit, Lady Cilento Children's Hospital, Brisbane, Queensland 4101, Australia.
⁹ Paediatric Intensive Care Unit, Lady Cilento Children's Hospital, Brisbane, Queensland 4101, Australia.
¹⁰ Département de Biochimie, de Microbiologie et de Bioinformatique, Université Laval, Québec, Canada.
¹¹ Centre for Children's Health Research, 62 Graham St, South Brisbane, Queensland 4101, Australia.
¹² Academic Discipline of Paediatrics and Child Health, School of Clinical Medicine, The University of Queensland, 501 Stanley St, South Brisbane, Queensland 4101, Australia; Department of Respiratory and Sleep Medicine, Lady Cilento Children's Hospital, 501 Stanley St, South Brisbane 4101, Australia.
¹³ International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: l.morawska@qut.edu.au.

Abstract

The paediatric intensive care unit (PICU) provides care to critically ill neonates, infants and children. These patients are vulnerable and susceptible to the environment surrounding them, yet there is little information available on indoor air quality and factors affecting it within a PICU. To address this gap in knowledge we conducted continuous indoor and outdoor airborne particle concentration measurements over a two-week period at the Royal Children's Hospital PICU in Brisbane, Australia, and we also collected 82 bioaerosol samples to test for the presence of bacterial and viral pathogens. Our results showed that both 24-hour average indoor particle mass (PM₁₀) (0.6-2.2μgm^-3, median: 0.9μgm^-3) and submicrometer particle number (PN) (0.1-2.8×10³pcm^-3, median: 0.67×10³pcm^-3) concentrations were significantly lower (p<0.01) than the outdoor concentrations (6.7-10.2μgm^-3, median: 8.0μgm^-3 for PM₁₀ and 12.1-22.2×10³pcm^-3, median: 16.4×10³pcm^-3 for PN). In general, we found that indoor particle concentrations in the PICU were mainly affected by indoor particle sources, with outdoor particles providing a negligible background. We identified strong indoor particle sources in the PICU, which occasionally increased indoor PN and PM₁₀ concentrations from 0.1×10³ to 100×10³pcm^-3, and from 2μgm^-3 to 70μgm^-3, respectively. The most substantial indoor particle sources were nebulization therapy, tracheal suction and cleaning activities. The average PM₁₀ and PN emission rates of nebulization therapy ranged from 1.29 to 7.41mgmin^-1 and from 1.20 to 3.96pmin^-1×10¹¹, respectively. Based on multipoint measurement data, it was found that particles generated at each location could be quickly transported to other locations, even when originating from isolated single-bed rooms. The most commonly isolated bacterial genera from both primary and broth cultures were skin commensals while viruses were rarely identified. Based on the findings from the study, we developed a set of practical recommendations for PICU design, as well as for medical and cleaning staff to mitigate aerosol generation and transmission to minimize infection risk to PICU patients.

Keywords: Airborne bacteria; Airborne particle number and mass; Hospital airborne infection; Indoor air; PICU air quality.

MeSH terms

Aerosols / analysis*
Air Pollutants / analysis*
Air Pollution, Indoor / analysis*
Australia
Bacteria / isolation & purification
Environmental Monitoring / methods
Intensive Care Units, Pediatric*
Particle Size
Viruses / isolation & purification

Substances

Aerosols
Air Pollutants