The purpose of this study was to determine whether using a standard method of endotracheal suctioning, to ensure consistent use of available knowledge, had any impact on patient care. Using experimental study design, the results of two different methods of suctioning in a cardiovascular surgery intensive care unit were compared. One method was the suctioning procedure applied by the nurses working in the intensive care unit. The other one, standard suctioning procedure, was developed based on the related literature and applied to the patients assigned to the experimental group by the researcher herself. Mean arterial blood pressure (MAP), heart rate (HR), and arterial blood gases (ABGs) were measured before the procedure, immediately after, 5 and 15 minutes after the procedures for both control and experimental group. The majority of the nurses suctioning the control group did not evaluate the ABGs after endotracheal suctioning, none of these patients was given oxygen both before and after the suctioning, and suctioning took longer time than recommended. To compare the results of the two different methods, the values of MAP, HR, PO2 (arterial oxygenation), PCO2 (arterial carbondioxide), and HCO3- (hydrogen carbonate) 15 minutes after the procedure were used, and the differences between the two methods were statistically significant (P < 0.05).