A child weighing 12.6 kg requires a 20 mL/kg fluid bolus to be administered over 25 minutes.

What is the infusion rate in milliliters per hour (mL/hr) that the nurse should set on the IV pump? Round your answer to the nearest tenth and enter only digits (not units).

Choice A rationale

The sweat chloride test is the gold standard diagnostic test for cystic fibrosis (CF). CF is caused by a mutation in the CFTR gene, which impairs chloride ion transport across epithelial cells. This defect leads to abnormally high chloride concentration in sweat, typically >60 mEq/L in children, which provides biochemical confirmation of the disease.

Choice B rationale

Pulmonary function tests (PFTs) measure lung volumes and airflow, typically revealing an obstructive pattern in CF due to chronic infection and inflammation. While they monitor disease progression and severity, PFTs are not diagnostic for the underlying genetic disorder that defines cystic fibrosis.

Choice C rationale

A Chest X-ray (CXR) may show characteristic findings of chronic lung disease in CF, such as bronchiectasis, hyperinflation, or atelectasis, reflecting the disease's pulmonary complications. However, the CXR is an imaging tool for assessing lung structure, not a diagnostic test for the systemic genetic condition itself.

Choice D rationale

Sputum cultures are used to identify the specific bacterial pathogens, such as Pseudomonas aeruginosa or Staphylococcus aureus, colonizing the airways of CF patients. While essential for guiding antibiotic therapy, a sputum culture only detects secondary infection and does not confirm the diagnosis of cystic fibrosis.

Choice A rationale

Furosemide is a loop diuretic that promotes the excretion of sodium and water, reducing fluid overload and pulmonary congestion associated with congestive heart failure. A decreased urine output of 0.5 mL/kg/hr is a sign of worsening status, as the target output for adequate diuresis is generally 1-3 mL/kg/hr for children.

Choice B rationale

Furosemide therapy is intended to reduce fluid volume, which should result in weight loss. An increase in weight of 1.5 kg indicates fluid retention and ineffective or inadequate diuretic therapy, signaling a deterioration or lack of improvement in the child's congestive heart failure.

Choice C rationale

A decrease in respiratory rate from 50 to 32 breaths per minute indicates a reduction in tachypnea. Tachypnea in congestive heart failure is caused by fluid backup into the lungs (pulmonary congestion), which decreases lung compliance. The reduction in rate suggests that the diuretic has successfully lowered the pulmonary fluid volume, improving respiratory function.

Choice D rationale

An increase in heart rate to 160 bpm (tachycardia) in a school-aged child (normal resting heart rate ≈ 70-110 bpm) is a compensatory mechanism for decreased stroke volume, often seen in worsening heart failure or dehydration. This finding indicates deterioration or a negative effect of the diuretic, such as volume depletion.