Competing interests
M. Mensi reports grants, personal fees and non-financial support from E.M.S. – Electro Medical Systems, E. Caselli declares that she has no conflict of interest, M. D’Accoliti declares that he has no conflict of interest, I. Soffritti declares that she has no conflict of interest, R. Farina declares that he has no conflict of interest, E. Scotti reports grants, personal fees and non-financial support from E.M.S. – Electro Medical Systems, M.E. Guarnelli declares that she has no conflict of interest, C. Fabbri declares that she has no conflict of interest, G. Garzetti reports personal fees from E.M.S. outside the submitted work – Electro Medical Systems, S. Marchetti declares that she has no conflict of interest, A. Sordillo reports personal fees from E.M.S. – Electro Medical Systems outside the submitted work, L. Trombelli reports grants and non-financial support from E.M.S. – Electro Medical Systems.