Randomised trial of daily interruption of sedative infusions in adult medical-surgical intensive care unit

INTERVENTION: Daily interruption of sedative infusions. If during this process the patient needs sedation again then the sedation restarts at half the previous dose and adjusted to reach the desired level of sedation. CONDITION: Sedation in critically ill patients ; Signs and Symptoms ; Sedation PRIMARY OUTCOME: 1. Duration of stay in intensive care ; 2. Duration of mechanical ventilation ; 3. Length of stay in the hospital SECONDARY OUTCOME: 1. Mortality in the intensive care ; 2. Mortality in the hospital; 3. Doses of sedatives; 4. Number of diagnostic tests of the brain INCLUSION CRITERIA: Critically ill patients receiving sedation for 48 hours.