Development for "Pulm Ex" and "Airway Ex's" coronavirus updates began in early March, as cases started to grow within the United States. When development kick-started, resources on best practices for emergency care were slim, and Glassenberg turned to "a bunch of disparate PDFs in Italian" that had been put together by SIAARTI, the Italian Anesthesia Society. At the time, Italy was the world's epicenter for the virus. Later came guidelines from the Centers for Disease Control and Prevention, the World Health Organization, the American Society of Anesthesiologists and more, all of which were used to build these new coronavirus updates.