Correct Answer: A

Rationale: The correct answer is A: Contractions of the sternocleidomastoid muscle. Contractions of the sternocleidomastoid muscle suggest that the client is using accessory muscles to breathe, which is a clear sign of respiratory distress. This finding indicates that the client is working harder to breathe, typically seen in conditions like asthma, COPD, or respiratory failure. Choices B, C, and D are not the most indicative of respiratory distress. A respiratory rate of 20 breaths/min falls within the normal range. Downward movement of the diaphragm with inspiration is a normal finding indicating effective diaphragmatic breathing. A pulse oximetry reading of SpO2 95% is within the normal range and does not necessarily indicate respiratory distress.

Correct Answer: C

Rationale: Crackles in the lungs indicate pulmonary congestion in a client with left-sided heart failure and require immediate intervention to prevent respiratory failure. Crackles suggest fluid accumulation in the lungs, leading to impaired gas exchange and potentially respiratory distress. Shortness of breath, jugular venous distention, and peripheral edema are common manifestations of heart failure but do not directly indicate acute respiratory compromise like crackles in the lungs do.

Correct Answer: D

Rationale: The correct answer is D, narrow therapeutic index. Narrow therapeutic index (NTI) drugs are defined as those drugs where small differences in dose or blood concentration may lead to serious therapeutic failures or adverse drug reactions. Choices A, B, and C are not directly related to the risk of drug toxicity. Low bioavailability (Choice A) refers to the amount of drug that enters the bloodstream unchanged after administration. Rapid onset of action (Choice B) and short half-life (Choice C) are characteristics related to drug effectiveness and metabolism but do not necessarily indicate a higher risk of drug toxicity.

Correct Answer: C

Rationale: A positive Chvostek's sign indicates hypocalcemia, a common complication following thyroidectomy due to inadvertent parathyroid gland injury. Immediate intervention is needed to prevent severe hypocalcemia symptoms like tetany, seizures, and laryngospasm. Hoarse voice and slight difficulty swallowing are expected post-thyroidectomy and do not require immediate intervention. Pain at the incision site is common postoperatively and can be managed with appropriate pain relief measures.

Correct Answer: C

Rationale: In a client with hyperglycemic hyperosmolar syndrome (HHS), a serum osmolarity of 320 mOsm/kg is the most concerning laboratory value. This high osmolarity indicates severe dehydration, which can lead to serious complications. Elevated serum glucose levels (choice A) are expected in HHS but do not directly reflect dehydration. Blood pressure (choice B) and serum pH (choice D) are important parameters to monitor but are not the most concerning values in HHS compared to serum osmolarity.