Background: The purpose of our study was to evaluate an inexpensive and available method to reduce mucous impactions in mechanically ventilated patients.Methods: This randomized clinical trial was conducted on 40 mechanically ventilated patients aged 15-90 years. The patients were randomly allocated into two arms; 20 cases and 20 controls. The cases received N-acetylcysteine via their nebulizers, and the control group received normal saline three times a day for one day. We measured the density of respiratory secretion, plateau and peak airway pressures, and O2 saturation at baseline, 12 and 24 hours later.Results: Although the mean secretion density was significantly lower in the NAC group (F (1, 38)=8.61, P=0.006), but a repeated measures ANOVA with a Greenhouse-Geisser correction determined that the effect of NAC on mean secretion density did not differ significantly between time points (F (1, 38)=3.08, P=0.087). NAC increased O2 saturation significantly between time points (F (1.92, 73.1)=4.6, P=0.014). The plateau airway pressures were relatively stable throughout the study in the normal saline and NAC groups (F (1.95, 37.1)=0.67, P=0.513). The peak airway pressure did not change significantly during the study in the normal saline and NAC groups (F (1.52, 56.4)=0.91, P=0.384).Conclusion: Considering the limitations of the study, nebulized NAC in mechanically ventilated patients was not effective more than normal saline nebulization in reducing the density of mucous plugs. The peak and plateau airway pressures were relatively stable throughout the study in both groups.
Trial Registration Number: IRCT201104276312N1