Objective: High flow nasal cannula (HFNC) plays role in many indications of oxygen therapy. Unfortunately, in middle income with a developing country like Thailand, HFNC is totally imported and high cost. For this whole reason, we would like to conduct DIY HFNC for comparing the efficacy with the standard marketing machine (Airvo-2).
Materials and Methods: The present study was an experimental study. The DIY HFNC was generated from our many medical equipment. Targeted gas flow and fractional oxygen (FiO2) were calculated by gas concentration stoichiometry formula. The efficacy of DIY HFNC was measured gas flow, FiO2 compared with the standard machine.
Results: Testing DIY HFNC when set-flow of 30 liters/min (L/m) and set-FiO2 in the range of 30 to 60% show achieved-flow in the range of 29.30 to 34.48 L/m (relative different (Δ) -2.33 to 14.93%), achieved-FiO2 as 30.60, 41.80, 52.50 and 60.50% (Δ2, 4.50, 5 and 0.83%, respectively). The next set-flow of 40 L/m and set-FiO2 in the range of 40 to 60% show achieved-flow in the range of 42.28 to 45.25 L/m (Δ10.70 to 13.13%), achieved-FiO2 as 41.50, 51.50 and 60.50% (Δ3.75, 3 and 0.83%, respectively). The next set-flow of 50 L/m and set-FiO2 at 60% show achieved-flow as 57.09 L/m (Δ14.18%), achieved-FiO2 as 60.10% (Δ0.17%). The last set-flow of 60 L/m and set-FiO2 at 60% show achieved-flow as 68.98 L/m (Δ14.97%), achieved-FiO2 as 63% (Δ5%). All usage periods give the same measure values.
Conclusion: The DIY HFNC shows the efficacy nearby the standard machine in gas flow range of 30 to 60 L/m and FiO2 range of 30 to 60%.

Keywords: High flow nasal cannula (HFNC); Do it by yourself (DIY)