What does an elevated partial pressure of oxygen (PaO2) indicate?

Elevated PO2 refers to a significant increase in the number of red blood cells, hemoglobin concentration, and hematocrit per unit volume of blood above the reference values.

PO2, or partial pressure of oxygen in the blood, normally ranges between 95–100 mmHg. When arterial oxygen partial pressure falls below 95 mmHg, it typically indicates varying degrees of hypoxia in the patient. Clinically, the diagnosis of hypoxemia is generally based on conditions at sea level while breathing ambient air containing 20.9% oxygen, with an arterial PO2 below 60 mmHg considered diagnostic for hypoxemia. A value below 60 mmHg suggests hypoxemia and may lead to symptoms such as dizziness, cyanosis of the lips, and increased heart rate.

High PO2 levels in the body are mainly associated with respiratory acidosis and metabolic alkalosis. In cases of respiratory acidosis, continuous low-concentration oxygen therapy is recommended, usually with an oxygen concentration below 35%. Long-term low-concentration oxygen therapy can reduce pulmonary circulation resistance and pulmonary artery pressure, facilitating carbon dioxide elimination. Mechanical ventilation, by adjusting relevant parameters, can increase ventilation and effectively remove carbon dioxide. For patients with metabolic alkalosis, potassium chloride can be administered intravenously or orally under medical supervision to promote renal excretion of bicarbonate and lower carbon dioxide levels in the body.

Patients with elevated PO2 should ensure adequate rest, avoid excessive fatigue, and maintain a positive mood in daily life.