The definition of CIM will be based on pathology muscular biopsy (quadriceps). Patients will undergo biopsy on the 1st and 11th day after entering the study. The technique of Gomori Trichrome will be used to determine the existence or absence of myopathy. In addition the ATPase technique will be applied at different prices of PH (PH: 9,4, PH: 4,6 and PH : 4.3), thus achieving a separation of myopathy and neuropathy.