Hostname: page-component-8448b6f56d-tj2md Total loading time: 0 Render date: 2024-04-23T06:28:15.767Z Has data issue: false hasContentIssue false
  • English
  • Français

Bubbling Humidifiers Produce Microaerosols Which Can Carry Bacteria

Published online by Cambridge University Press:  02 January 2015

Frank S. Rhame ,
Andrew Streifel ,
Carter McComb  and
Mike Boyle
Frank S. Rhame*
Affiliation:
Infection Control Program and Cardio-Respiratory Services, University of Minnesota Hospitals and Clinics, the Infectious Diseases Section, Department of Medicine, Department of Laboratory Medicine and Pathology, Epidemiology Division, School of Public Health, and Department of Anesthesiology, University of Minnesota School of Medicine, and the Department of Environmental Health and Safety, University of Minnesota
Andrew Streifel
Affiliation:
Infection Control Program and Cardio-Respiratory Services, University of Minnesota Hospitals and Clinics, the Infectious Diseases Section, Department of Medicine, Department of Laboratory Medicine and Pathology, Epidemiology Division, School of Public Health, and Department of Anesthesiology, University of Minnesota School of Medicine, and the Department of Environmental Health and Safety, University of Minnesota
Carter McComb
Affiliation:
Infection Control Program and Cardio-Respiratory Services, University of Minnesota Hospitals and Clinics, the Infectious Diseases Section, Department of Medicine, Department of Laboratory Medicine and Pathology, Epidemiology Division, School of Public Health, and Department of Anesthesiology, University of Minnesota School of Medicine, and the Department of Environmental Health and Safety, University of Minnesota
Mike Boyle
Affiliation:
Infection Control Program and Cardio-Respiratory Services, University of Minnesota Hospitals and Clinics, the Infectious Diseases Section, Department of Medicine, Department of Laboratory Medicine and Pathology, Epidemiology Division, School of Public Health, and Department of Anesthesiology, University of Minnesota School of Medicine, and the Department of Environmental Health and Safety, University of Minnesota
*
Box 421, Mayo Memorial Building, University of Minnesota Hospitals and Clinics, Minneapolis, MN 55455
Get access Rights & Permissions [Opens in a new window]

Abstract

It is widely held that bubbling humidifiers do not produce microaerosols, although prior studies have resulted in conflicting evidence. We have studied this phenomenon in a clean room using an airborne particle counter and samplers for airborne bacteria. At gas flow rates between 10 and 80 L/min, a Cascade 1 humidifier produced between 460 and 999 water droplets/L humidified gas. Total water volume aerosolized was approximately 10-8 ml/L humidified gas. Seventy-three percent of the particles had diameters between 1 and 5 microns. With the reservoir containing 6.4 × 106P. aeruginosa/ml, it produced between 2 and 9 P. aeruginosa/Lhumidified gas. Most of the bacteria were in particles of a size likely to be deposited in the lung. This bacterial carryover was between 20 and 150 times the amount predicted by multiplication of the water volume aerosolized times the concentration of bacteria in the humidifier reservoir. An Air Life humidifier produced fewer particles which were also of a size likely to be deposited in the lung and, when the reservoir contained P. aeruginosa, it aerosolized bacteria. Wick-type humidifiers did not produce detectable aerosol or bacterial carry-over. Although the clinical significance of these findings has not been established, they provide a rationale for the CDC recommendations for procedures designed to keep bubbling humidifier reservoir water uncontaminated.

Type
Original Articles
Information
Infection Control & Hospital Epidemiology , Volume 7 , Issue 8 , August 1986 , pp. 403 - 407
Copyright
Copyright © The Society for Healthcare Epidemiology of America 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Reinarz, JA, Pierce, AK, Mays, BB, et al: The potential role of inhalation therapy equipment in nosocomial pulmonary infection. J Clin invest 1965; 44:831–839.Google Scholar
2.Sanders, CV Jr, Luby, JP, Johanson, WG Jr, et al: Serratia marcescens infections from inhalation therapy medication: Nosocomial outbreak. Ann Intern Med 1970; 73:15–21.CrossRefGoogle ScholarPubMed
3.Schulze, T, Edmondson, EB, Pierce, AK, et al: Studies of a new humidifying device as a potential source of bacteria aerosols. Am Rev Respir Dis 1967; 96:517–519.Google Scholar
4.Craven, DE, Connolly, MG Jr, Lichtenberg, DA, et al: Contamination of mechanical ventilators with tubing changes every 24 or 48 hours. N Engl J Med 1982; 306:1505–1509.CrossRefGoogle ScholarPubMed
5.Simmons, BP, Wong, ES: Guidelines for prevention of nosocomial pneumonia. Infect Control 1982; 3:1–9.CrossRefGoogle Scholar
6.Anderson, AA: New sampler for the collection, sizing, and enumeration of viable airborne particles. J Bacteriol 1958; 76:471–484.Google Scholar
7.Tomaides, M, Whitby, KT: Generation of aerosols by bursting of single bubbles, in Liu, BYH (ed): Fine Particles: Aerosol Generation, Measurement, Sampling, and Analysis. New York, Academic Press, 1976, pp 235–252.Google Scholar
8.Ahlgren, EW, Chapel, JF, Dorn, GL: Pseudomonas aeruginosa infection potential of oxygen humidifier devices. Respiratory Care 1977; 22:383–385.Google Scholar
9.Vesley, D, Anderson, J, Halben, MM, Wyman, L: Bacterial output from three respiratory therapy humidifying devices. Respiratory Care 1979; 24:228–234.Google ScholarPubMed
10.Palleroni, NJ: Pseudomonas, in Krieg, NG, Holt, JG (eds): Bergey's Manual of Systematic Bacteriology. Vol. 1. Baltimore, Williams and Wilkins, 1984, p 165.Google Scholar
11.Favero, MS, Peterson, NJ, Carson, LA, et al: Gram-negative water bacteria in hemodialysis systems. Health Laboratory Science 1976; 12:321–334.Google Scholar
12.Gaudin, AM, Mular, AL, O'Connor, RF: Separation of microorganisms by flotation. I. Development and evaluation of assay procedures. Applied Microbiology 1960; 8:84–90.CrossRefGoogle ScholarPubMed
13.Gaudin, AM, Mular, AL, O'Connor, RF: Separation of microorganisms by flotation. II. Flotation of spores of Bacillus subtilis var. niger. Applied Microbiology 1960; 8:91–97.Google Scholar
14.Blanchard, DC, Syzdek, LD: Water-to-air transfer and enrichment of bacteria in drops from bursting bubbles. Appl Environ Microbiol 1982; 43:1001–1005.Google Scholar
15.Trapana, Y, MacIntyre, DS Jr, Holzman, BH, et al: Surveillance study of pediatric patients receiving respiratory therapy, using the Bain circuit system. Am J Infect Control 1982; 10:128–132.Google Scholar
16.Harris, TM, Raman, TK, Richards, WJ, et al: An evaluation of bacterial contamination of ventilator humidifying systems. Chest 1973; 63:922–925.CrossRefGoogle ScholarPubMed
17.Malecka-Griggs, B, Reinhardt, DJ: Direct dilution sampling, quantitation, and microbial assessment of open-system ventilation circuits in intensive care units. J Clin Microbiol 1983; 17:870–877.CrossRefGoogle ScholarPubMed
18.Deane, RS, Shinozaki, T, Morgan, JG, et al: A method of maintaining sterility of heated humidifiers in mechanical ventilator breathing circuits. Crit Care Med 1978; 6:60–63.CrossRefGoogle ScholarPubMed
19.Craven, DE, Goularte, TA, Make, BJ: Contaminated condensate in mechanical ventilation circuits. A risk factor for nosocomial pneumonia? Am Rev Respir Dis 1984; 129:625–628.Google Scholar