In a normal heart: The right side pumps oxygen-poor blood to the lungs. The left side pumps oxygen-rich blood to the body. In mixed heart defects: Blood may travel through the wrong vessel. One side of the heart may be underdeveloped. Pulmonary and systemic blood may mix in one chamber or vessel. Blood may not reach the lungs or body effectively. Oxygen saturation may remain low even with oxygen therapy. RN priority: Do not assume oxygen alone will correct cyanosis. Many of these defects require prostaglandin E1, cardiac catheterization, staged surgery, or urgent transfer to pediatric cardiac care. For NCLEX-RN (Canada), items rarely announce the topic in the first sentence. Anchor to objective data, trajectory, and the safest next step for the role named in the stem before distractors compete. On the exam, writers often pair stable-sounding options with unstable data—notice the mismatch before you commit. If the stem names a license or role, reread that line; scope errors are classic trap answers even when the clinical topic is familiar. Run a 60-second scan: breathing work and oxygenation, perfusion and...