The effects of Thymus vulgaris inhalation therapy on airway status and oxygen saturation of patients under mechanical ventilation: A randomized clinical trial

Background and Objective: A wide range of intensive care patients on a ventilator are at risk for pneumonia and atelectasis. Thymus vulgaris essential oil administered by nebulization has been proposed as potentially useful in preventing these complications. The present study aimed to determine the effect of Thymus vulgaris inhalation therapy on airway status and oxygen saturation in patients under mechanical ventilation. 

Materials and Methods: This randomized clinical trial performed on 66 patients on a ventilator in two groups. The experimental group received the Thymus vulgaris essential oil (four drops of pure Thymus vulgaris essential oil with 10 mL distilled water) every eight hours for 30 minutes in three days through a nebulizer. The control group received 10 mL of distilled water every eight hours for 30 min in three days through a nebulizer. A questionnaire collected information on socio-demographic characteristics and clinical parameters, and a checklist used to record variables related to airway status (weight, volume, the concentration of secretions; respiratory sounds; airway plateau pressure; airway maximum pressure) and oxygen saturation. 

Findings: The concentration of airway secretions in the experimental group was significantly lower than that of the control group (p < 0.001, F = 61.901). The mean airway maximum pressure was significantly decreased (p < 0.001, F = 17.315) and showed a significant difference in the mean oxygen saturation at 8 am and 10 am between the day before the intervention and the first to third days after intervention in the experimental group (p < 0.001, F = 13.972). 

Conclusion: Thymus vulgaris inhalation therapy diminished the concentration of airway secretions through increasing the volume and reduced the weight of secretions, and decreased the airway maximum pressure through a decline in the stimulation of the airway. It also facilitated the discharge of mucous membranes, improved gas exchange, and increased the oxygen saturation of patients under mechanical ventilation through direct stimulation of the mucosa, increasing the secretion of the airway mucosa, and increasing the activity and movements of the respiratory tract cilia. Therefore, Thymus vulgaris inhalation therapy may be recommended to improve the condition of the respiratory tract in patients under mechanical ventilation.