A nurse is reinforcing teaching about diagnostic tests with the parents of a child who has suspected cystic fibrosis. Which of the following diagnostic tests should the nurse include as the most definitive when diagnosing cystic fibrosis?

A. Overriding aorta: In Tetralogy of Fallot, the aorta is positioned over the ventricular septal defect (VSD), rather than solely over the left ventricle as it would be in a normal heart. This is called overriding aorta, which allows blood from both the right and left ventricles to enter the aorta.

B. Pulmonary stenosis: This is a critical component of Tetralogy of Fallot. Pulmonary stenosis refers to narrowing of the pulmonary valve or the area just below it, which restricts blood flow from the right ventricle to the pulmonary artery. This results in decreased blood flow to the lungs for oxygenation.

C. Left ventricular hypertrophy: This choice is not typically associated with Tetralogy of Fallot. Left ventricular hypertrophy refers to an enlargement or thickening of the muscular wall of the left ventricle of the heart. It is often seen in conditions where the left ventricle has to work harder to pump blood, such as in hypertension or aortic stenosis, but it is not a characteristic feature of Tetralogy of Fallot.

D. Ventricular septal defect: This defect is one of the four components of Tetralogy of Fallot. A ventricular septal defect (VSD) is a hole in the septum, the muscular wall that separates the left and right ventricles of the heart. In Tetralogy of Fallot, the VSD allows oxygen-poor blood from the right ventricle to flow directly into the left ventricle and out to the body.

A. "Your child's diet should be high in carbohydrates & proteins with no restriction of fats."

This statement is not entirely accurate. While it's true that children with cystic fibrosis often require a diet that is higher in calories and protein to support growth and weight gain, there is typically a need to restrict fat intake. Pancreatic insufficiency, which is common in cystic fibrosis, can lead to malabsorption of fats and fat-soluble vitamins. Therefore, a dietitian may recommend enzyme replacement therapy and a diet that is moderate in fat but high in calories and protein.

B. "Limit your child's intake of sodium to avoid complications."

This statement is not accurate. Cystic fibrosis can lead to excessive loss of salt in sweat, which can contribute to dehydration and electrolyte imbalances. Therefore, limiting sodium intake can cause electrolyte disturbances.

C. "A pigeon-shaped chest might become evident as the disease progresses."

This statement is accurate. Cystic fibrosis can cause chronic lung infections and inflammation, leading to structural changes in the chest over time. One common manifestation is a barrel-shaped or "pigeon-shaped" chest, which can occur as the disease progresses. This may result from hyperinflation of the lungs due to air trapping and chronic respiratory compromise.

D. "Administer a bronchodilator to the child after chest percussion therapy."

This statement is not necessarily accurate or applicable to all cases. Bronchodilators are medications used to help relax and open the airways in conditions such as asthma or chronic obstructive pulmonary disease (COPD). While bronchodilators may be part of the treatment regimen for some individuals with cystic fibrosis, their use after chest percussion therapy would depend on the individual's specific respiratory symptoms and treatment plan. It's important for the parents to follow the healthcare provider's instructions regarding medication administration.