Correct Answer: B

Rationale: The correct answer is to limit screen time when preventing childhood obesity. Excessive screen time is associated with a sedentary lifestyle and can lead to increased consumption of unhealthy foods. Encouraging high-calorie snacks (choice A) contradicts the goal of preventing obesity. While fast food as an occasional treat (choice C) can be acceptable in moderation, it should not be encouraged as a preventive measure against obesity. Allowing the child to eat freely (choice D) without guidance can lead to overconsumption of unhealthy foods and contribute to obesity risk.

Correct Answer: B

Rationale: The correct answer is B: Tissue oxygen needs. Polycythemia occurs as the body's response to chronic hypoxia by increasing RBC production to enhance oxygen delivery. In tetralogy of Fallot, a congenital heart defect, the heart's structure causes reduced oxygen levels in the blood. This chronic hypoxia stimulates the bone marrow to produce more red blood cells, leading to an elevated RBC count. Choice A is incorrect as low blood pressure is not directly related to polycythemia in this context. Choice C, diminished iron level, is not the cause of polycythemia in tetralogy of Fallot. Choice D, hypertrophic cardiac muscle, is not the primary cause of the elevated RBC count in this case.

Correct Answer: C

Rationale: When a dysrhythmia is suspected, an important nursing responsibility is to count the apical pulse for 1 full minute and then compare this rate with the radial pulse rate. This method helps in identifying dysrhythmias as it allows for a direct comparison of the heart's rhythm at two different pulse points. Ordering an immediate electrocardiogram (Choice A) may be necessary but should not be the first step. Counting the radial pulse multiple times (Choice B) is not as accurate as comparing rates directly. Having someone else take the radial pulse simultaneously (Choice D) may introduce errors and inconsistencies in the measurement.

Correct Answer: C

Rationale: The correct preoperative intervention for a child with pyloric stenosis is to monitor for signs of dehydration. Pyloric stenosis involves the obstruction of the pyloric sphincter, leading to projectile vomiting, which can result in dehydration and electrolyte imbalances. Monitoring for signs of dehydration is crucial to assess the child's fluid status and prevent complications. Administering intravenous fluids, although important in managing dehydration, is not typically a preoperative intervention but rather a treatment during or after surgery. Monitoring for signs of infection and pain may also be important but are not the priority preoperative interventions in a child with pyloric stenosis.

Correct Answer: B

Rationale: When an adolescent with type 1 diabetes experiences an insulin reaction, it is essential to quickly raise their blood sugar levels. Buying a soda and a hamburger to eat is the best choice in this situation as it provides a fast-acting source of sugar to counteract hypoglycemia. Calling parents immediately may cause a delay in receiving appropriate treatment. Administering insulin would further lower blood sugar levels, worsening the situation. Leaving the arena and resting would not address the immediate need to raise blood sugar levels.