Things to note when doing blood gas analysis

With the development of medicine, many examination instruments are becoming more and more sophisticated, especially blood gas analyzer, which has become a popular examination method in recent years. You should know more about the precautions for blood gas analysis. During the examination, the blood sampling site should be arterial blood; care should be taken to prevent the blood sample from coming into contact with the air; and attention should also be paid to the sample placement time, which should generally be used within thirty minutes.

1. Blood sampling site: The specimen for blood gas analysis is arterial blood, which can truly reflect the body's oxidative metabolism and acid-base balance. Common blood sampling sites are the brachial artery, femoral artery, forearm artery, etc. Arterialized capillary blood can also be used, but the PO2 is lower than that of arterial blood. Venous blood can also be used for blood gas determination, but it is quite different from arterial blood.

2. Choice of anticoagulant: Since whole blood gas needs to be measured, anticoagulation is necessary, and heparin is generally used for anticoagulation (lithium heparin is suitable, with a concentration of 500-1000U/ml).

3. Be careful to prevent the blood sample from coming into contact with air and keep it isolated from air. Contact with air can increase PO2, decrease PCO2 and contaminate blood samples.

4. Sample storage time: It is advisable to test within 30 minutes. Otherwise, the active RBC metabolism in the whole blood will continuously consume O2 and produce CO2, which will affect the accuracy of the result. If the sample cannot be detected within 30 minutes, it should be kept in ice water for no more than 2 hours.