Can isolated negative-pressure devices reduce transmission of respiratory infection in critical care units: A laboratory-based controlled experimental observational study.

BACKGROUND

Healthcare workers in critical care settings are at increased risk of acquiring respiratory infections, particularly during aerosol-generating procedures (AGPs). Portable negative-pressure isolation devices have been proposed to fix airborne infection in isolation rooms.

OBJECTIVE

To evaluate whether an isolated negative-pressure device reduces bacterial and fungal aerosol dispersion under controlled laboratory conditions.

METHODS

This laboratory-based controlled experimental observational study assessed aerosol containment across three techniques: (1) no cover, (2) plastic sheet canopy barrier, and (3) a portable negative-pressure isolation system. Standardized 5 mL suspensions of Staphylococcus epidermidis and Aspergillus flavus were nebulized on three separate days for each technique. Nutrient agar plates were placed and colony-forming units (CFU) were manually counted. The primary outcome was the mean CFU per technique per day. One-way ANOVA with post-hoc Welch's t-tests (Bonferroni-corrected) was used for statistical comparison.

RESULTS

A total of 36 bacterial and fungal plates were analysed. For bacterial aerosols, mean CFU was highest with no cover (535.6 ± 5.38), lower with plastic sheet canopy barrier (429.5 ± 5.41), and lowest with the negative-pressure system (217.5 ± 17.5). Differences were statistically significant (ANOVA p = 9.8 × 10-8; η2 = 0.995). Fungal CFU demonstrated a similar pattern with significantly lower CFU for Technique 3 compared with both other techniques (p < .001).

CONCLUSION

The negative-pressure isolation device significantly reduced airborne dispersion of bacterial and fungal aerosols compared with plastic sheet canopy barrier methods. These findings support the use of portable negative-pressure systems to enhance aerosol containment during AGPs. Further clinical validation is recommended.