Disclosed herein is a portable ventilator and a method for providing an oscillatory flow to a subject in need thereof. The method comprises: (a) forming a gas mixture comprising pure oxygen and air； (b) converting the gas mixture into the oscillatory flow by applying thereto a predetermined oscillatory frequency and a predetermined ventilatory duration； (c) outputting the oscillatory flow of the step (b) at a first jet pressure, in which the outputted oscillatory flow has a first flow rate； and (d) modulating the outputted oscillatory flow of the step (c) by, (i) varying the respective amounts of the pure oxygen and the air in the gas mixture； or (ii) varying the predetermined ventilatory duration of the step (b), in which if the fist jet pressure is smaller than the predetermined jet pressure, then decreases the predetermined ventilatory duration； or if the first jet pressure is greater than the predetermined jet pressure, then increases the predetermined ventilatory duration.本揭示內容關於一種可攜式呼吸器以及用以對一亟需之個體提供一振盪氣流的方法。該方法包含： (a) 形成一混合氣體，其包含純氧及空氣；(b) 藉由對該混合氣體施加一預定振盪頻率及一預定換氣期間，將該混合氣體轉換成該振盪氣流；(c) 以一第一噴射壓力輸出該步驟(b)之該振盪氣流，其中該輸出振盪氣流具有一第一流速；以及(d) 透過以下步驟調變步驟(c)之該輸出振盪氣流：(i) 調整該混合氣體中該純氧及該空氣各自含量；或是(ii) 調整該步驟(b)之該預定換氣期間，其中，若該第一噴射壓力小於該預定噴射壓力，則減少該預定換氣期間；或若該第一噴射壓力大於該預定噴射壓力，則增加該預定換氣期間。
