Prophylaxis of venous thromboembolism in general surgery in Spain. Analysis of a national survey Juan Ignacio Arcelus Martínez; Beatriz Leiva Jiménez; Lorena Ruiz Barrera; Manuela Expósito Ruiz; Nuria Muñoz Pérez; Jesús Villar del Moral; José Luis Díez Vigil; Cristina López Espada;