Calculation method of oxygen and index

The oxygenation index (OI) refers to the percentage obtained by dividing the arterial oxygen partial pressure (PaO2) by the inhaled oxygen concentration (FiO2). Expressed by the formula, it is the oxygenation index (OI)=PaO2/FiO2.

Used to indicate the degree of acute lung injury, the normal value is 400~500mmHg. In acute respiratory distress syndrome, due to severe intrapulmonary shunt, the arterial oxygen partial pressure is obviously reduced. Increasing oxygen concentration can not increase the arterial oxygen partial pressure, and the arterial oxygen partial pressure is not obvious, so the oxygenation index is often less than 300mmHg.

What is oxygen and index?

Oxygenation index is a goal in respiratory therapy, and it is an important index to make organs and tissues get enough oxygen for oxygenation to get energy.

What is arterial oxygen partial pressure?

Oxygen partial pressure is the pressure generated by oxygen molecules dissolved in blood. Because the partial pressure of oxygen is related to the utilization of oxygen by cells, the lower limit of the normal range of peers is called hypoxemia.

Calculation method of inhaled oxygen concentration

The concentration of inhaled oxygen has a certain relationship with the flow rate of inhaled oxygen. Generally speaking, the oxygen concentration in the air is 2 1%. When inhaling oxygen, if the nasal catheter is used to inhale oxygen, the oxygen flow rate per liter per minute and the concentration will increase by 4%. For example, if the oxygen flow rate is 5L/ min, the oxygen concentration will be 465,438+0%, and the nasal catheter cannot inhale more than 5L/ min. If you use a mask or ventilator to absorb oxygen, you can also calculate it according to this method, but because of the limited air mixing, the oxygen flow can reach more than 90%.