The normal range of blood gas analysis, generally includes the following indicators. 1, acidity and alkalinity is also known as PH value, the normal range of PH value is between 7.35-7.45, 7.4 is the middle value. The normal value of partial pressure of carbon dioxide is 35-45 mmHg, if it is greater than 50 mmHg, it belongs to the category of primary respiratory acidosis, and less than 35 mmHg is the category of primary respiratory alkalosis. 3, we should also look at bicarbonate, the concentration of bicarbonate is generally between 22 and 27, if it is greater than 27, it is metabolic acidosis. If it is greater than 27, it is metabolic alkalosis and less than 22, it is metabolic acidosis. Therefore, the normal range of blood gas analysis mainly depends on the three indicators, which are combined to determine whether they belong to respiratory factors or metabolic factors, or even mixed factors. In addition, partial pressure of oxygen is also an important indicator, normal in 95-100mmHg, if less than 80mmHg, it indicates hypoxemia, if less than 60mmHg, enter the stage of respiratory failure, is one of the indicators to give oxygen to the patient.