oxyhemoglobiinia

Oxyhemoglobiinia, also known as oxyhemoglobinemia, is the state in which oxyhemoglobin constitutes the majority of hemoglobin in the circulating blood. It results from oxygen binding to hemoglobin in the lungs, forming oxyhemoglobin (HbO2) from deoxyhemoglobin (HHb). The extent of oxyhemoglobinemia depends on arterial oxygen tension (PaO2), the alveolar-arterial gradient, the amount of hemoglobin, and factors that influence the oxyhemoglobin dissociation curve, such as pH, CO2, temperature, and 2,3-bisphosphoglycerate.

Measurement and interpretation are based on oxygen saturation and content. Oxyhemoglobin saturation is commonly assessed by pulse oximetry (SpO2) and co-oximetry, while arterial oxygen content (CaO2) can be calculated from hemoglobin concentration, SaO2, and PaO2. The term describes oxygenated hemoglobin and is not itself a disease. It is distinguished from conditions involving other forms of hemoglobin, such as deoxyhemoglobin, methemoglobin, or carboxyhemoglobin, which affect oxygen delivery and the interpretation of oxygenation measurements.

Clinical relevance centers on assessing oxygenation status. Oxyhemoglobiniemia reflects adequate oxygen binding in the arterial circulation, which is expected under normal resting conditions and during effective oxygen therapy. In clinical practice, attention tends to focus on identifying hypoxemia (low SaO2/PaO2) or the presence of abnormal hemoglobin species that can impair oxygen transport despite high PaO2. The concept helps distinguish normal oxygenation from pathological states that disrupt delivery of oxygen to tissues.