Effect of Endotracheal Suctioning With and Without Normal Saline on Arterial Blood Gas valus Among Mechanically Ventilated Patient. A Quasi-Experimental Study

Abstract

Background: Endotracheal suctioning is a common procedure in mechanically ventilated patients to maintain airway patency. The use of normal saline instillation prior to suctioning remains controversial due to its potential impact on arterial blood gas (ABG) values. Objective This quasi-experimental study aimed to evaluate the effect of endotracheal suctioning with and without normal saline on arterial blood gas values in mechanically ventilated adult patients and determine which of the two methods (with or without saline) is more effective in improving oxygenation and reducing airway resistance.

Methods: A quasi-experimental design was used in the study. This study was initiated from 19th September 2024 to 30th July 2025 at the ICU at Imam Al-Hussein Medical City and the ICU unit of Imam Al-Hassan Al-Mujtaba Teaching Hospital in Holy Kerbala, Iraq. In Kerbala, purposive sampling was used to select the participants. A total of patients receiving mechanical ventilation in the intensive care unit (ICU) were enrolled. Patients were divided into two groups: one group received endotracheal suctioning with normal saline instillation, and the other without saline. Arterial blood gas parameters (PaO₂, PaCO₂, and pH) were measured before and after the procedure. Statistical analysis was conducted using SPSS version .

Results: The results showed no statistically significant differences between the two groups in demographic characteristics, except for shorter ICU stay in the saline group (p = 0.037). This group achieved significant improvements in arterial blood gas values, with PaO₂ increasing and PaCO₂ decreasing as pH stabilized. Effect sizes were large for respiratory volume and ventilation pressures. In contrast, the untreated group recorded limited changes, with small effect sizes. The study also demonstrated a significant effect of some demographic factors, such as age and medical diagnosis, on physiological responses at a significant rate within each group.

Conclusion: Endotracheal suctioning with normal saline instillation resulted in more favorable outcomes in terms of gas exchange compared to suctioning without saline. The use of N/S appears to improve secretion clearance, ventilation efficiency, and oxygenation, supporting its clinical utility in mechanically ventilated patients.

Recommendations: The use of saline prior to tube suctioning is recommended in the presence of thick secretions or inadequate gas exchange, and its routine use should be avoided without necessity. Standardized suction protocols should be developed, supported by ongoing training and close monitoring of vital signs. The use of humidification or inhaled saline is also recommended to improve secretion fluidity. Finally, future studies are needed to evaluate the effect of the suctioning with normal saline instillation on infection and quality of care.