Prospective observational study on the use of continuous intravenous ketamine and propofol infusion for prolonged sedation in critical care Laura Torres Soblechero; Doris Elena Ocampo Benegas; Gema Manrique Martín; Laura Butragueño Laiseca; Andrea María Leal Barceló; Alejandro Parreño Marchante; Jesús López-Herce Cid; Santiago Mencía Bartolome;