Background: Benefits of non-invasive ventilation [NIV] has been proven as a modality of treatment for acute respiratory failure patients. However, there are few studies about the benefit of early use of NIV in dyspnea and hypoxemic patients.

Objective: To investigate the benefit of NIV in emergency patients with respiratory distress.

Materials and Methods: A prospective randomized controlled trial was conducted at the Emergency Department of Siriraj Hospital, to compare NIV and standard oxygen therapy [SOT] in patients with respiratory distress. The primary outcome was respiratory rate at 120 minutes after intervention.

Results: One hundred fourteen patients were randomized to receive SOT (57 patients) and NIV (57 patients). NIV could provide a significant decrease in respiratory rate at 120 minutes compared to SOT (p = 0.042). NIV was also associated with a significant improvement in pulse rate at 120 minutes (p = 0.001). No statistically significant differences were found in respiratory rate at 60 minutes, intubation, short-term mortality rate, and length of hospital stay between the two groups. Overall success rate of NIV was 86%.

Conclusion: NIV could rapidly reduce respiratory rate and pulse rate at 120 minutes compared to SOT in emergency patients with acute respiratory distress. However, there was no benefit of NIV in the reduction of length of hospital stay, intubation, and shortterm mortality rate.