Normal 95 - 100% Indications Determine respiratory status Part of Arterial Blood Gas (ABG) testing Description Oxygen saturation (SaO2) is a measurement of the percentage of how much hemoglobin is saturated with oxygen. Oxygen is transported in the blood in two ways: oxygen dissolved in blood plasma (pO2) and oxygen bound to hemoglobin (SaO2). About 97% of oxygen is bound to hemoglobin while 3% is dissolved in plasma. SaO2 and pO2 have direct relationships, if one is decreased so is the other. The relationship between oxygen saturation (SaO2) and partial pressure O2 (PaO2) is referred to as the oxyhemoglobin (HbO2) dissociation curve. SaO2 of about 90% is associated with PaO2 of about 60 mmHg. What would cause increased levels? Polycythemia Increased inspired O2 Hyperventilation What would cause decreased levels? Anemia’s Hypoventilation Bronchospasm Mucus plugs Atelectasis Pneumothorax Pulmonary edema Adult respiratory distress syndrome