What are the reasons for low oxygen?
When found in patients with reduced oxygen saturation, one by one from the following aspects should be considered to find the problem.
1, inhaled oxygen partial pressure is too low. When the oxygen content of inhaled oxygen can cause oxygen saturation decreased, should be combined with medical history, asked whether the patients have been to an altitude of 3000 m above the plateau, and altitude flight, diving after the rise, and poor ventilation in the mine.
2, whether there is airflow obstruction. To consider whether there is obstructive hypoventilation caused by diseases such as asthma and COPD, tongue base fall, airway secretions foreign body obstruction.
3, whether there is ventilation dysfunction. To think of patients with severe pneumonia, severe tuberculosis, diffuse pulmonary fibrosis, pulmonary edema, pulmonary embolism affect the ventilation function of the disease.
4, the quality and quantity of oxygen in the blood delivery of Hb how. Abnormal substances such as CO poisoning, nitrite poisoning, a significant increase in abnormal hemoglobin, not only seriously affect the transport of oxygen in the blood, but also seriously affected the release of oxygen.
5, whether the patient has the appropriate colloid osmotic pressure and blood volume. Appropriate colloid osmotic pressure and adequate blood volume is one of the key factors to maintain normal oxygen saturation.
6, the patient's cardiac output how. Maintain the normal oxygen volume of organs should have enough cardiac output to support.
7, tissue and organ microcirculation. The ability to maintain proper oxygenation is also linked to the body's metabolism. When the body's metabolic capacity is too high, the venous oxygen content will be significantly reduced. Venous blood will cause more severe hypoxia after shunting the pulmonary circulation.
8, the use of oxygen in the surrounding tissue. Tissue cells can only use free oxygen, and oxygen associated with Hb is released only for tissue utilization. Changes in PH, 2,3-DPG, etc. affect oxygen dissociation from Hb.
9, after excluding all the above factors, do not forget may be due to equipment failure due to oxygen saturation.