Noninvasive Positive-Pressure Ventilation : An Experimental Model to Assess Air and Particle Dispersion
|Journal / Publication||Chest|
|Publication status||Published - Sep 2006|
|Link to Scopus||https://www.scopus.com/record/display.uri?eid=2-s2.0-33748857154&origin=recordpage|
Methods: Airflow was marked with intrapulmonary smoke for visualization. Therapy with inspiratory positive airway pressure (IPAP) was started at 10 cm H2O and gradually increased to 18 cm H2O, whereas expiratory positive airway pressure was maintained at 4 cm H2O. A leakage jet plume was revealed by a laser light sheet and images captured by video. Smoke concentration in the plume was estimated from the light scattered by smoke particles.
Findings: A jet plume of air leaked through the mask exhaust holes to a radial distance of 0.25 m from the mask during the application of IPAP at 10 cm H2O with some leakage from the nasal bridge. The leakage plume exposure probability was highest about 60 to 80 mm lateral to the median sagittal plane of the HPS. Without nasal bridge leakage, the jet plume from the exhaust holes increased to a 0.40-m radius from the mask, whereas exposure probability was highest about 0.28 m above the patient. When IPAP was increased to 18 can H2O, the vertical plume extended to 0.45 m above the patient with some horizontal spreading along the ward ceiling.
Conclusion: Substantial exposure to exhaled air occurs within a 0.5-m radius of patients receiving NPPV. Medical wards should be designed with an architectural aerodynamics approach and knowledge of air/particle dispersion from common mechanical ventilatory techniques.
- Air and particle dispersion, Influenza, Noninvasive positive-pressure ventilation
Noninvasive Positive-Pressure Ventilation : An Experimental Model to Assess Air and Particle Dispersion. / Hui, David S.; Hall, Stephen D.; Chan, Matthew T.V.; Chow, Benny K.; Tsou, Jin Y.; Joynt, Gavin M.; Sullivan, Colin E.; Sung, Joseph J.Y.In: Chest, Vol. 130, No. 3, 09.2006, p. 730-740.