Processes for the conversion of a major ambulatory surgery unit into an intensive care unit due to the COVID-19 syndemic. Cross-sectional study - Gemio-Del Rey,I.A.; García-Blanco,A.; Pérez-López,B.; Sabater-Maroto,C.; Sanz-Villaverde,A.; de la Plaza-Llamas,R. (Cirugia y Cirujanos, 2025)