A nurse is reviewing the BUN result of a client who is taking cyclosporine following a kidney transplant. Which of the following laboratory studies should the nurse recognize as another renal function study that should be monitored?

Rationale:
A. "Supplement breastfeedings with water every 12 hours.": Breastfed infants do not require water supplementation because breast milk provides adequate hydration. Giving water can reduce milk intake, interfere with nutrition, and increase the risk of electrolyte imbalance.

B. "Limit the time your infant feeds to 10 minutes on each breast.": Feeding duration should be guided by the infant’s cues rather than a strict time limit. Limiting feeds can prevent the infant from receiving the hindmilk, which is richer in fat and essential for growth.

C. "Begin each feeding using the same breast.": Alternating the starting breast for each feeding helps ensure equal stimulation and milk production in both breasts. Starting with the same breast consistently may lead to uneven milk supply.

D. "Offer your infant the breast when he shows signs of hunger.": Responsive, cue-based feeding supports adequate nutrition, growth, and bonding. Feeding on demand—such as rooting, sucking on hands, or fussiness—helps establish and maintain milk supply and meets the infant’s needs effectively.

Rationale:
A. Skin warm and dry: Warm, dry skin indicates adequate circulation and fluid balance. In fluid overload, the skin is often cool and moist due to peripheral vasodilation and increased interstitial fluid. Therefore, this finding is not consistent with overhydration.

B. Respiratory rate 30/min: Tachypnea is a key indicator of fluid overload because excess fluid can accumulate in the lungs, leading to pulmonary congestion and decreased gas exchange. The body compensates by increasing the respiratory rate to improve oxygenation and remove excess carbon dioxide.

C. Heart rate 60/min: A normal heart rate suggests stable cardiovascular status. Fluid overload typically causes tachycardia as the heart works harder to manage increased circulatory volume, not a normal or bradycardic rate.

D. Tenting skin turgor: Tenting indicates dehydration, not fluid overload. In overhydration, the skin is usually taut and edematous due to excess interstitial fluid accumulation rather than loss of elasticity.