The nurse is evaluating a female child with acute post-streptococcal glomerulonephritis for signs of improvement. Which finding typically is the earliest sign of improvement?

Obstructive congenital heart defects involve the presence of narrowing or constriction in various parts of the heart or major blood vessels. In the case of coarctation of the aorta, there is a narrowing or constriction in the aorta, which can obstruct blood flow. Aortic stenosis involves the narrowing of the aortic valve, and pulmonic stenosis involves the narrowing of the pulmonary valve. These defects create obstacles to the normal flow of blood out of the heart, leading to increased pressure within the heart and affecting blood circulation.

The other categories mentioned are:

B. Mixing defects: These defects involve abnormal mixing of oxygenated and deoxygenated blood within the heart, typically due to septal defects like atrial septal defect (ASD) or ventricular septal defect (VSD).

C. Decreased pulmonary blood flow: These defects are characterized by reduced blood flow to the lungs, such as in the tetralogy of Fallot.

D. Increased pulmonary blood flow: These defects involve increased blood flow to the lungs, often due to shunting of blood from the left side of the heart to the right side, as seen in atrial septal defects or ventricular septal defects.

Hypercyanotic spells, also known as "Tet spells," can occur in infants with congenital heart defects, particularly tetralogy of Fallot. During these spells, there is a sudden decrease in oxygen saturation, leading to cyanosis (blueness) of the infant's skin and lips, as well as respiratory distress and possible loss of consciousness.
The knee-chest position is a specific technique used to manage hypercyanotic spells. Placing the child in this position helps improve oxygenation by increasing systemic vascular resistance and reducing the degree of right-to-left shunting of blood in the heart. It also increases venous return to the heart, which can help improve cardiac output.

Now, let's discuss why the other options are incorrect:
A. Prepare family for imminent death: This is not the priority action. While hypercyanotic spells can be life-threatening, the immediate focus should be on managing the spell to improve oxygenation and prevent further deterioration. Preparing the family for death should only be considered if resuscitation measures fail, which is not the first-line intervention.
C. Assess for neurologic defects: Assessing for neurologic defects is important but not the immediate priority during a hypercyanotic spell. The primary concern at this moment is addressing cyanosis and respiratory distress to ensure the infant receives adequate oxygen.
D. Begin cardiopulmonary resuscitation: Initiating CPR is not the initial priority during a hypercyanotic spell. CPR would be indicated if the infant's condition deteriorates to the point of cardiac arrest, but it should not be the first step. Placing the child in the knee-chest position is a non-invasive intervention that should be attempted before considering CPR.