This study was designed to determine the effects of saline solution administered prior to endotracheal suctioning by nurses working in intensive care on oxygenation, heart rate and long-term pulmonary hygiene. The study was carried out on an experimental basis in the Intensive Care Unit of a university hospital in Turkey. A total of 20 patients were included, who were mechanically ventilated because of pulmonary or cardiovascular problems or trauma. Data were collected using a data form. Each patient was monitored for 5 minutes following suctioning with or without saline solution and findings of heart rate, SpO2, and blood gas measurements were recorded. Data were analysed using percentage calculations, the student's t-test and the Friedman test. The study showed that most of the patients were between 60 and 69 years and were intubated because of respiratory insufficiency. Evaluation of blood gases following suctioning with or without saline solution showed partial decreases in pO2, pCO2, HCO3, and oxygen saturation (SaO2), which did not reach a significant level. No significant difference was found between pH levels recorded prior to and 5 minutes after suctioning without saline solution; however, the increase in pH following suctioning with saline solution was significant. Patients undergoing suctioning with saline solution exhibited significantly increased heart rates in the fourth and fifth minutes, whereas no increases were detected in these undergoing suctioning without saline solution. SpO2 values obtained by pulse oxymeter did not show significant differences. Saline solution administered with suctioning resulted in undesirable, although not significant, alterations in oxygen saturation and arterial blood gas levels.