Abstract Introduction The China Health Authority alerted the World Health Organization (WHO) of several cases of pneumonia, and the WHO has declared the novel coronavirus (COVID-19) a global pandemic. Mastoidectomy is a high-risk aerosol generating procedure with the potential to expose the surgeon to infectious particles. Objective Aim to develop a low-cost prototype for a barrier device that can be used during mastoidectomy. Methods Describe the steps involved during otological emergency, requiring immediate surgical procedure, in untested patients. The Otorhinolaryngology Surgical Team of Walter Cantídio Hospital developed the barrier for particle dispersion presented here. Results During surgery, the prototype did not compromise visualization of the surgical field and instrumentation. Microscope repositioning was not compromised or limited by tent Instrumentation and instrument pouch under the Microscope-Tent (MT) performed surgery. After surgery, the plastic sheet was removed simply, without requiring strength. Bone dust and irrigation droplets were collected on the tent. Conclusion Our team developed and practiced, in an otologic emergency, a low-cost and reproducible barrier device that can be used in mastoidectomy in COVID-19 patients. Further tests on efficacy may be necessary.