Comparison of the effects of two levels of negative pressure in open endotracheal tube suction on the physiological indices among patients in intensive care units

BACKGROUND: Most of the patients admitted in the intensive care units (ICUs) require an endotracheal tube and mechanical ventilation. In order to clear and maintain patency of the airways, endotracheal suctioning is required. Therefore, the least detrimental way of endotracheal tube suctioning which can diminish the complications should be selected. The present study aimed to compare the effect of two levels of negative pressure (100 mmHg and 200 mmHg) in open endotracheal tube suction on the physiological indices among patients in the ICUs. MATERIALS AND METHODS: In this single-blind clinical trial, 60 patients meeting the inclusion criteria were selected by convenience sampling and randomly allocated in two groups. First group of patients were suctioned with negative pressure of 100 mmHg and the second group with 200 mmHg. Effects of two levels of suction pressure on oxygen saturation (SPO2) and heart rate (HR) values were measured and recorded at four time points. Repeated measure analysis of variance (ANOVA), Chi-square test, and independent t-test were adopted to analyze the data. RESULTS: In the two groups consisting of totally 60 subjects (30 in each group), 34 subjects were males and 26 were females, with a mean age of 60.63 years (minimum 18 years and maximum 75 years). Repeated measure ANOVA showed a significant difference in the mean SpO2 and HR before, during, and 5 and 20 min after suction within each group (P < 0.05), but not between the two groups (P > 0.05). CONCLUSIONS: The present study revealed that with regard to the detrimental effect of endotracheal tube suctioning on arterial oxygen saturation and HR, suctioning with negative pressure of 200 mmHg is considered to be a low-risk procedure compared to suctioning with negative pressure of 100 mmHg, if standard procedures in open suction system are followed.