Methods: A handheld GE V-Scan™ with Dual Probe ultra-sound was available for use by physicians in the main medical tent. All treating physicians consented to participate and self-reported their training and proficiency using POCUS. After each use of POCUS, physicians completed a survey recording the indication, scans performed, and impact on diagnosis, management, and disposition of patients. Results: In total, POCUS was used on 28 patients out of the 686 patients seen in the main medical tent. The three most common indications for ultrasound were abdominal pain, gynecological complaints, and dyspnea. POCUS narrowed the differential diagnosis in 64% (18/28) and altered the working diagnosis in 21% (6/28) of patients. It confirmed the management plan in 57% (16/28) and altered it in 39% (11/28) of patients. Use of POCUS reduced the burden on the local healthcare infrastructure in 46% (13/28) of patients and prevented ambulance transport to a higher level of care in 32% (9/28) of patients. Conclusion: Physicians reported that POCUS aided in the diagnosis, management, and disposition of select patients at a remote multi-day mass gathering. POCUS helped to reduce the local healthcare burden caused by hosting a large-scale mass gathering by preventing or altering the urgency of transport to hospital for higher level care or diagnostic imaging. Study/Objective: To present information on an organization of health services and risk preparedness during the 2016 Rio de Janeiro Olympic Games. Background: Mass gatherings of international importance occur frequently in Brazil, especially in Rio de Janeiro. In 2014 and 2016 the country received two global sports events-the 2014 Fifa World Cup, and the 2016 Olympic Games in several Brazilian state capitals and in Rio. These events joined a great contingent of people and demanded the health sector to prepare for reception of incoming participants and visitors. Methods: The 'Prepara Brasil' Project investigated health services preparedness in Rio de Janeiro. A literature-based data collection instrument to assess available health infrastructure, health services and safety risks concerning the 2016 Olympic Games was made available online for spectators in all Olympic events. Filling out the survey form in real time and directly from the sports venues, was voluntary and participation was maximized through snowballing. After the Games data was accrued and analyzed. Results: A total of 61 spectators, 70% of which were university graduates completed the form. Participants attended 26 events in 42 different sports, during 17 of the 19 days of competition. Roughly 45% of respondents clearly identified locations of health services in Olympic venues. Inside the arenas, 17% of respondents could point out health services and health services personnel at a maximum distancing 50 meters or less (.3 mi) from their seats. Half of participants identified emergency exits and escape routes, and 80% considered safety measures in sports venues as strict. According to participants, crowding was obser...