Sztrymf et al. 2011 associated Optiflow with sustained and beneficial benefits on oxygenation and clinical parameters in patients with acute respiratory failure. His study showed that after 15 minutes of initiating Optiflow, a significant improvement is observed concerning respiratory rate and oxygenation, while dyspnea score, clinical signs of respiratory distress, and heart rate after 30 minutes.
Similarly, Rittayamai et al. 2013 showed significant improvement in post-extubation patients and found that as early as 5 minutes after initiating Optiflow, improvement in respiratory rate was observed and heart rate, oxygenation, and dyspnea score after 10 minutes.
These studies are suggesting a time window to observe how a patient is responding to the therapy. Titrate flow and/or oxygen to meet the desired outcome for the patient.

1. Sztrymf et al. Intensive Care Med. 2011
2. Rittayamai et al. Respir Care, 2014.
3. Lenglet et al. Respir Care, 2015.
4. Rittayamai et al. Respir Care, 2015.