Background:Mechanical ventilation is one of the supporting treatments that are used for different reasons. To reduce patients’ inconvenience caused due to using tracheal tube and ventilator, sedation is routinely used. Using scales for the sedation, for example, Richmond Agitation Sedation Scale (RASS), may reduce dose of sedation and length of mechanical ventilation.Materials and Methods:This study is a randomized clinical trial on 64 patients selected from three intensive care units (ICUs) in Isfahan, Iran. Through random allocation, 32 patients were assigned to each of the study and control groups. In the control group, patients’ level of consciousness and the amount of drug consumption in every shift, based on physician order, were recorded. In the study group, RASS score was recorded every hour and sedation was administered based on that. The purpose of the study was to investigate of application of RASS for drug consumption until weaning of the patient from the ventilator. Independent t-test with significance level of 0.05 was used.Results:Results showed no significant difference in the mean consumption of midazolam and morphine after intervention, but there was a significant difference in fentanyl (P = 0.03) consumption (379 μg in the control group vs 75 μg in the study group) between groups after the intervention. The mean duration of being connected to the ventilator was significantly less in the study group (P = 0.03).Conclusions:Application of RASS by nurses leads to a decrease in sedation consumption, connection to ventilator, and length of stay in the hospital.