For patients with respiratory illness weakened lungs, their own lack of respiratory function, serious and even symptoms of oxygen and we breathe in oxygen and diluted by the air in the lungs, so the real concentration of oxygen in the lungs has dropped a lot, so emphysema patients need the 90% concentration of oxygen to breathe. The FiO2(fraction of inspire O2)%=21+4x（L/min）
So, that for a patient, they should choose a high purity oxygen concentrator and suitable flow rate oxygen concentrator. We can provide 1-60LPM oxygen concentrators for health care and medical use. Welcome to send your enquire!