Final answer:
Central cyanosis is triggered by a decrease in arterial blood oxygen saturation or the presence of abnormal hemoglobin, commonly caused by respiratory issues like RDS in premature infants or congenital heart defects like tetralogy of Fallot and patent foramen ovale.
Step-by-step explanation:
Central cyanosis is characterized by blue discoloration of the lips and mucous membranes. It occurs due to reduced oxygen saturation of arterial blood or abnormal hemoglobin that cannot carry oxygen effectively. Respiratory and cardiac conditions are the primary causes. Respiratory Distress Syndrome (RDS), often found in premature infants, leads to inadequate lung function due to insufficient pulmonary surfactant production. This prevents proper inflation of the lungs at birth, causing low blood oxygen levels and cyanosis. Similarly, congenital heart defects such as tetralogy of Fallot and patent foramen ovale lead to insufficiently oxygenated blood reaching the body, prompting cyanosis especially during activities.
Metabolic issues like metabolic acidosis may also cause cyanosis by reducing the blood's ability to carry oxygen. Other symptoms that can accompany central cyanosis include possible cherry-red skin, confusion, nausea, gasping for air, seizures prior to death, and metabolic acidosis. Whether due to respiratory or cardiac causes, any condition that leads to a significant decrease in arterial oxygen saturation can manifest as central cyanosis. Thus, a variety of issues ranging from structural heart problems to lung dysfunction can result in this clinical sign.