Normal pressure oxygen therapy indicates absorbing oxygen under normal air pressure. Oxygen resource of normal-pressure oxygen therapy must be the pure oxygen conforming to medical oxygen supply standard, that's to say its oxygen concentration must not below 99.5%. However, the normal-pressure oxygen therapy usually adopts single-side earplug to absorb pure oxygen but non-closed type breathing mask can be adopted as well. In this way, the pure oxygen absorbed will mix with ambient air absorbed through the other nostril in nasal cavity or mix with ambient air in breathing mark so that the oxygen entering into tracheal is the oxygen-rich air whose oxygen content is 23 ～ 26% approximately.

Calculation Formula of Oxygen Concentration in Normal Pressure Oxygen Therapy:

Concentration of absorbed oxygen (%) 一 21 ＋ 4×pure oxygen supply flux/min

For instance, when pure oxygen supply flux is 1L/min every minute the concentration of absorbed oxygen is 25%.

Beijing Fuxing Hospital Kidney Internal Medicine once carried through a scientific experiment: patients with chronic renal failure will turn into classic oxygen deficient condition after accepting acetate hemodialysis and will recover gradually only after 24 hours generally. The doctors chose 20 trial volunteers which have no disease on heart and lung from patients with late-stage renal failure, and then take the blood from them to measure blood oxygen content 30 minutes later since them accepting hemodialysis. After that, the doctors let them absorb oxygen at different flux immediately. When they finish absorbing oxygen, the doctors will take blood from them to measure blood oxygen content again. Experimental results see the form.

Experimental result of blood oxygen content enhancement after oxygen absorption

Beijing Jishuitan Hospital Emergency Treatment Section also carried through clinical observation on oxygen absorption at one time. Among 30 male and female patients for emergency treatment, 12 cases are emphysema or bronchial asthma acute attacks, 10 cases are coronary heart disease, paroxysmal angina and heart failure and others are 3 cases of pulmonary heart disease Ⅱ grade heart failure, 2 cases of chronic bronchitis, 1 case of cerebral infarction, 1 case of spontaneous pneumothorax and 1 case of hysteria.

After these patients for emergency treatment absorbed oxygen for 20 ～ 30 minutes (500 ～ 1000ml/min), their critical symptoms all got efficiently alleviated. According to effective and apparent effect standards (systolic pressure of high blood pressure descending 10mmHg or above means apparently effective, over-speed heart rate descending 10 times or so means effective and 20 times means apparently effective, patients stuffy in the chest descending 4 times/min means effective and above 4 times/min means apparently effective and double lung singing of patients feeling much oppressed descending one + means effective and two + means apparently effective), the total effective rate reached 100% and apparently-effective rate reached 13%.Considering oxygen absorption is one of necessary first aid treatments, effect mentioned above completely proves excellent effect of normal-pressure oxygen supply used in emergency treatment. Therefore, normal-pressure oxygen therapy is effective and safe and especially suitable for self oxygen therapy, self oxygen health care and first aid.