Article Text

Download PDFPDF
Effect of portable negative pressure units on expelled aerosols in the operating room environment
  1. Marko Popovic1,
  2. Jonathan Beathe1,2,
  3. Ejiro Gbaje1,
  4. Marla Sharp1 and
  5. Stavros G Memtsoudis1,2,3
  1. 1 Department of Anesthesiology, Critical Care & Pain Management, Hospital for Special Surgery, New York, New York, USA
  2. 2 Department of Anesthesiology, Weill Cornell Medicine, New York, New York, USA
  3. 3 Department of Health Policy and Research, Weill Cornell Medical College, New York, NY, USA
  1. Correspondence to Dr Stavros G Memtsoudis, Hospital for Special Surgery Department of Anesthesiology Critical Care & Pain Management, New York, NY 10021, USA; memtsoudiss{at}


Introduction Spontaneously breathing patients undergoing procedures under regional anesthesia can expose operating room personnel to infectious agents. The use of localized negative pressure within proximity of a patient’s airway is expected to reduce the amount of bioaerosols dispersed particularly for anesthesia staff who are frequently near the patient’s airway.

Methods In the experiment, aerosols were produced using a polydisperse aerosol generator with nebulized saline. A portable negative pressure unit was set up at set distances of 10 cm and 30 cm with the aim of reducing aerosol particle counts detected by a laser-based particle counter.

Results Without the portable negative pressure unit, the median concentration of 0.5 µm aerosols detected was 3128 (1533, 22832) particles/ft3/min. With the portable negative pressure unit 10 cm and 30 cm from the site of aerosol emittance, the median concentration compared with background concentration was −0.5 (−8, 8) particles/ft3/min and 398 (89, 1749) particles/ft3/min, respectively.

Conclusions For particle concentrations of 0.5 µm, 0.7 µm, and 1.0 µm a significant amount of aerosol reduction was observed (p<0.001). Further experiments are warranted to assess the safety of staff when encountering a potentially infectious patient in the operating room.

  • COVID-19

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Twitter @sgmemtsoudis

  • Contributors MP: Carried out the experiment, wrote the manuscript with input/contributions from entire team, analyzed and interpreted results. JB: Devised and supervised the project, analyzed and interpreted results. EG: Performed statistical analysis, analyzed and interpreted results, helped in writing manuscript. MS: Helped design the project along with working out most of the technical problems prior to experiment start. In charge of planning project and logistics. SGM: Conceived original idea, devised and supervised the project, Manuscript writing and editing, analyzed and interpreted results. Guarantor. All Authors provided feedback that helped to shape the project, analysis and manuscript

  • Funding Hospital for Special Surgery Department of Anesthesiology Research and Education Fund.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.