Negative Pressure Tent to Reduce Exposure of Health Care Workers to SARS CoV-2 During Aerosol Generating Respiratory Therapies

Many patients who are admitted with coronavirus disease 2019 pneumonia could benefit from high-flow nasal oxygen or noninvasive ventilation to address hypoxemia and/or the work of breathing, but the use of these modalities has been associated with transmission of infection to health care workers.¹ Here we describe the creation of a simple negative pressure tent (Fig 1 ) that can be placed over individual patients who are being treated anywhere within a hospital where wall suction is available. These tents are similar in appearance to the oxygen tents that were used commonly in the late 19th and early 20th centuries; instead of filling them with oxygen, wall suction is used to create negative pressure to remove aerosols generated within the tent. They are inexpensive to manufacture (approximately $100), are easy to build on site, are highly scalable to meet the demands of individual institutions, and will slide easily under the mattress of most hospital beds. In this configuration, we measured in excess of 22 air changes per hour, which exceeds the Centers for Disease Control and Prevention recommendation of 12 air changes per hour for negative pressure isolation rooms. This simple design can maintain negative pressure with oxygen flow rates of >60 L/min entering the tent. Health care workers wearing personal protection equipment can lift the edge of the tent to provide care without exposing their faces. Updraft nebulizer aerosol tests and cough tests that use florescent powder demonstrated no visible contamination outside of the tent. During simulations, there was no measurable accumulation of CO₂ within the tent. Fire hazards are always a concern when medical oxygen is used; however, oxygen concentrations within the tent never exceeded 43% with the simulated high flow devices at 60 L/min. The schematics and additional photographs and videos of these isolation tents can be found in e-Appendix 1. Modification of this design to fit the table dimensions of special procedure suites and operating rooms is accomplished easily. We feel that this simple design is an inexpensive, rapidly deployable, and practical method to improve health care worker safety during the coronavirus disease 2019 pandemic.

Figure 1.

Negative pressure tent deployed in a simulated non-negative pressure hospital room.