Alveolar-arterial partial pressure of oxygen (PA-aDO2)

The alveolar-arterial oxygen partial pressure difference (A-aDO2) is the difference between the alveolar oxygen partial pressure and the arterial oxygen partial pressure. This value can be used as a clinical judgment for lung ventilation. It is used to judge the ventilation function of the lungs, and it can reflect the oxygen uptake of the lungs more sensitively than PaO2. Helps to understand the progress of lung lesions. Can be used as a reference indicator for mechanical ventilation or for weaning. Basic Information Specialist classification: Respiratory examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Some drugs can affect the pH of the blood. The doctor should inform the doctor about the recent medication before the test. Normal value It is 20mmHg when sucking air. Less than 70mmHg when sucking pure oxygen. The child is 5mmHg (0.66 kPa). Normal young people average 8mmHg (1.06 kPa). 60 to 80 years old can reach 24mmHg (3.2 kPa). Generally no more than 30mmHg. Clinical significance Abnormal results: Significantly increased indicates oxygenation dysfunction in the lungs. At the same time, the oxygen partial pressure is significantly reduced, often lower than 60mmHg, usually caused by short circuit in the lungs, such as atelectasis and adult-type respiratory distress syndrome, the absorption of pure oxygen can not be corrected. Moderately increased hypoxemia, usually inhaled pure oxygen, is expected to be corrected, such as chronic obstructive pulmonary disease. Hypoxemia caused by insufficient ventilation, if the alveolar-arterial oxygen partial pressure difference is normal, it suggests that the underlying cause is mostly absent from the lungs, and is likely to be insufficient for alveolar ventilation caused by central nervous system or neuro-muscular lesions. Need to check the crowd: In patients with ventilatory dysfunction in the lungs, patients with pulmonary lesions are informed by progress. Indications for mechanical ventilation. Precautions The forearm was immersed in warm water of 45 ° C for 20 minutes, and the appropriate amount of venous blood was taken out in a sealed clean tube, and sealed for examination. Requirements for inspection: 1. Conventional arterial blood should be taken for examination. If venous blood is to be taken, the forearm should be immersed in warm water at 45 °C for 20 minutes to make the venous blood arterial. It is not advisable to use a tourniquet when drawing blood. 2. Flush with heparin beforehand in the syringe. 3. Ensure that the needle and needle of the syringe are tightly combined, and there must be no air leakage to ensure that the blood sample does not come into contact with the outside air. 4. Send the specimen in time. Preparation before inspection: Certain drugs may affect blood pH, and the doctor should be informed of the recent medication before the test. Inspection process The forearm was immersed in warm water of 45 ° C for 20 minutes, and the appropriate amount of venous blood was taken out in a sealed clean tube, and sealed for examination. Not suitable for the crowd For non-invasive examinations, there is no suitable population. Adverse reactions and risks Dizziness or fainting: When blood is drawn, due to emotional overstress, fear, reflex caused by vagus nerve excitability, blood pressure drop, etc., the blood supply to the brain is insufficient to cause fainting or dizziness.