RN exams respiratory practice questions

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Asthma is an obstructive airway disease characterized by reversible bronchoconstriction, inflammation, and mucus production. During an asthmatic attack, narrowed airways increase resistance, particularly during expiration, when dynamic compression exacerbates airflow limitation, producing wheezing most prominent on expiration, not inspiration. The work of breathing increases significantly as patients struggle against this resistance and reduced airflow, requiring greater effort from respiratory muscles like the diaphragm and intercostals to maintain ventilation. Bronchodilators (e.g., albuterol) are the mainstay of treatment, relaxing bronchial smooth muscle to relieve constriction, so they are not contraindicated. Forced expiratory volume in 1 second (FEV1) decreases during an attack due to obstruction, not increases, as airflow is impeded. The increased work of breathing is a consistent expectation, reflecting the physiological burden of overcoming narrowed airways and trapped air, distinguishing it from the incorrect options that misalign with asthma's acute presentation.

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The correct answer is B: Excess alcohol intake. Alcohol consumption can contribute to the development of hypertension by increasing blood pressure and damaging the arteries over time. Excessive alcohol intake can also lead to weight gain and other unhealthy lifestyle choices that can exacerbate hypertension. A: A low-calcium diet is not a modifiable risk factor for the development of hypertension. Calcium intake may have some impact on blood pressure regulation, but it is not a primary modifiable risk factor for hypertension. C: A family history of hypertension is a non-modifiable risk factor as genetics play a significant role in the development of hypertension. While having a family history of hypertension increases one's risk, it is not something that can be changed or modified. D: Consumption of a high-protein diet is not a primary modifiable risk factor for hypertension. While diet plays a role in hypertension, high protein intake alone is not a significant risk factor compared to factors such as excessive alcohol consumption, high sodium intake, and obesity

Correct answer:

The correct answer is B: Excess alcohol intake. Alcohol consumption can contribute to the development of hypertension by increasing blood pressure and damaging the arteries over time. Excessive alcohol intake can also lead to weight gain and other unhealthy lifestyle choices that can exacerbate hypertension. A: A low-calcium diet is not a modifiable risk factor for the development of hypertension. Calcium intake may have some impact on blood pressure regulation, but it is not a primary modifiable risk factor for hypertension. C: A family history of hypertension is a non-modifiable risk factor as genetics play a significant role in the development of hypertension. While having a family history of hypertension increases one's risk, it is not something that can be changed or modified. D: Consumption of a high-protein diet is not a primary modifiable risk factor for hypertension. While diet plays a role in hypertension, high protein intake alone is not a significant risk factor compared to factors such as excessive alcohol consumption, high sodium intake, and obesity

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The volume of air entering the lung during inspiration is driven by Boyle's law: lung volume increases as intrapulmonary pressure decreases relative to atmospheric pressure. This pressure gradient is created by the diaphragm and intercostal muscles contracting, expanding the thoracic cavity, and dropping intrapulmonary pressure (e.g., from 760 mmHg to 758 mmHg), allowing air to flow in. Increasing this gradient via greater muscle contraction or thoracic expansion directly increases inspired volume, making it the primary factor. Increase in action potential' is vague but likely refers to neural impulses to respiratory muscles; while more frequent or intense action potentials could enhance muscle effort, this is secondary to the mechanical pressure gradient they produce. Combining both doesn't elevate action potentials to equal status, as pressure is the direct mechanism. Decreasing the gradient reduces airflow, opposing the goal. Thus, the pressure gradient is the most critical factor, as it's the physical driver of ventilation, rooted in respiratory mechanics.

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Idiopathic pulmonary fibrosis (IPF) is a restrictive lung disease marked by progressive scarring of the lung interstitium, reducing lung elasticity and function. Total lung capacity (TLC) decreases in IPF because fibrotic tissue stiffens the lungs, limiting their expansion. Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) are both reduced, but the FEV1/FVC ratio remains normal or elevated, unlike in obstructive diseases. Arterial oxygen partial pressure (PaO2) drops due to impaired gas exchange across thickened alveolar walls, leading to hypoxemia. However, total pulmonary vascular resistance (PVR) increases in IPF as fibrosis compresses and obliterates pulmonary capillaries, narrowing the vascular bed and elevating resistance to blood flow. This increase can strain the right heart, potentially causing cor pulmonale. Among the options, only total pulmonary vascular resistance is expected to be higher than normal, aligning with IPF's impact on the pulmonary vasculature rather than lung volumes or oxygenation, which decline.

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PCO2, or partial pressure of carbon dioxide, reflects the concentration of CO2 in blood, highest where metabolic waste accumulates and lowest where gas exchange removes it. The superior vena cava (SVC) carries deoxygenated blood from the upper body back to the heart, rich in CO2 from tissue metabolism, typically with a PCO2 of 45-46 mmHg, making it the highest among the options. Pulmonary veins carry oxygenated blood from the lungs to the heart after CO2 is offloaded in the alveoli, so their PCO2 is low (around 40 mmHg, arterial level). The midportion of pulmonary capillaries is where gas exchange occurs, transitioning from high venous PCO2 to lower arterial levels, averaging less than the SVC. Carotid bodies are chemoreceptors sensing blood gases, not a blood-containing structure, but even arterial blood they monitor has a PCO2 of about 40 mmHg. The SVC, as a major venous return vessel, consistently has the highest PCO2 due to its role in collecting metabolically produced CO2 before pulmonary gas exchange, distinguishing it from the other options.

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Infant respiratory distress syndrome (IRDS), or hyaline membrane disease, occurs in premature infants due to insufficient surfactant production by immature type II alveolar cells. Surfactant lowers alveolar surface tension (T), facilitating lung expansion. In IRDS, reduced surfactant leads to increased surface tension, causing alveoli to collapse (atelectasis) after each breath. This high tension decreases lung compliance (C), as the lungs become stiffer and harder to inflate, requiring greater pressure for ventilation. Consequently, collapsed alveoli impair gas exchange, reducing arterial oxygen partial pressure (PaO2) below normal (hypoxemia), often to levels like 50-60 mmHg instead of the typical 75-100 mmHg. The correct combination increased T, decreased C, decreased PaO2 reflects the pathophysiology of IRDS, where surfactant deficiency drives a cascade of respiratory challenges. Other combinations, like increased compliance or unchanged PaO2, contradict the condition's mechanics, where stiff lungs and poor oxygenation are hallmark features.

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Diffusion rate, per Fick's law, depends on surface area (choice A), concentration gradient (choice B), solubility (choice C), and membrane thickness (choice E), but not directly on molecular weight of gas (choice D), making D correct. Surface area increases diffusion by providing more space for gas exchange, as seen in alveoli. The concentration gradient (partial pressure difference) drives diffusion, e.g., Oâ‚‚ from alveoli to blood. Solubility affects how easily gases dissolve in the membrane, with COâ‚‚ diffusing faster than Oâ‚‚ due to higher solubility. Thickness inversely affects rate; thinner alveolar walls enhance diffusion. Molecular weight influences diffusion speed in free gas (Graham's law), but in the lung's aqueous environment, solubility dominates over molecular weight for Oâ‚‚ and COâ‚‚ exchange across membranes. Studies show diffusion capacity correlates with solubility and pressure gradients, not molecular weight, in physiological contexts, confirming D as the factor least affecting diffusion rate here.

Correct answer:

Fick's law of diffusion states that the rate of gas diffusion across a membrane (e.g., alveolar-capillary) is proportional to the surface area (A), diffusion coefficient (D), and partial pressure gradient (ΔP), and inversely proportional to diffusion distance (d): Rate = (A × D × ΔP) / d. When comparing different gases (e.g., O2 vs. CO2), the diffusion coefficient (D) varies most significantly, as it depends on gas solubility and molecular weight (D ∝ solubility / √MW). CO2's solubility is ~20 times higher than O2's (0.51 vs. 0.024 ml/mmHg/L), though O2's molecular weight is slightly lower (32 vs. 44), making CO2 diffuse ~20 times faster despite similar gradients. Partial pressure gradient drives diffusion but is gas-specific and often comparable (e.g., O2: 100-40 mmHg, CO2: 46-40 mmHg). Temperature and distance affect all gases similarly in the lung. Thus, the diffusion coefficient has the most pronounced effect across different gases, explaining why CO2 equilibrates faster than O2 across the respiratory membrane.

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The correct answer is C: Maintain a nonjudgmental attitude to avoid causing the client to feel guilty. This is important because the nurse needs to establish trust with the client to obtain accurate information about their health history. Being nonjudgmental creates a safe space for the client to share openly, which is crucial for effective assessment and planning of care. Choice A is incorrect because while it is important for the client to quit smoking, addressing this issue at the first encounter may not be the most effective approach and could potentially alienate the client. Choice B is also incorrect as the focus should be on building rapport and obtaining accurate information relevant to the client's current health status. Encouraging honesty about substance use is important but not the most critical action in this context. Choice D is incorrect as the nurse should provide information and support to the client based on the client's needs and wishes, rather than making assumptions about their preferences or prognosis.