LPN exams respiratory practice questions set 3

Correct answer:

The correct answer is A: Kinking of the ventilator tubing. This condition can cause a blockage in the airflow, leading to increased pressure in the ventilator circuit, triggering the high-pressure alarm. Kinking restricts the flow of air, causing a buildup of pressure in the system. This situation can lead to inadequate ventilation and potential harm to the patient. Choice B, a disconnected ventilator tube, would trigger a low-pressure alarm rather than a high-pressure alarm because the disconnection would result in a loss of pressure. Choice C, an endotracheal cuff leak, would not directly cause an increase in pressure within the ventilator circuit. Choice D, a change in oxygen concentration without resetting the alarm, would not trigger the high-pressure alarm but rather an oxygen alarm if the concentration falls outside the set range. In summary, kinking of the ventilator tubing is the correct answer as it directly leads to increased pressure in the ventilator circuit, triggering the high-pressure alarm.

Correct answer:

Diffusion of gases like O2 and CO2 across the alveolar-capillary membrane follows Fick's law: Rate = (A × D × ΔP) / d. Decreased surface area (A), as in emphysema, reduces the available exchange area, lowering diffusion. Increased fluid in the lung (e.g., pulmonary edema) increases diffusion distance (d), as fluid thickens the barrier, impeding gas transfer and often adding proteinaceous debris that further slows diffusion. Decreased pressure coefficient' likely intends partial pressure gradient (ΔP); reducing this (e.g., via hypoventilation) weakens the driving force for diffusion. All these factors surface area, distance, and gradient when altered as described, decrease diffusion rate. The diffusion coefficient (D) isn't directly mentioned, but the combined impact of the listed changes aligns with clinical scenarios (e.g., edema causing hypoxemia). Since each independently and collectively impairs diffusion, all contribute to a reduced gas exchange efficiency, critical for oxygenation and CO2 removal.

Correct answer:

Influenza poses greater risks to individuals with compromised immune systems, chronic illnesses, or developmental vulnerabilities. The grandmother with COPD faces heightened risk due to her chronic respiratory condition, which impairs lung function and makes flu complications like pneumonia more likely. The father with HIV has a weakened immune system, increasing susceptibility to severe flu outcomes. The newborn baby girl, with an immature immune system, is also at high risk, as infants under six months cannot receive the flu vaccine and struggle to fight infections. The mother with anemia, while possibly fatigued, does not have a condition that inherently heightens flu complication risks to the same degree. The 8-year-old boy, assuming no chronic conditions, is less vulnerable. The nurse must identify those most likely to suffer severe outcomes here, the grandmother, father, and newborn based on their health status and age-related vulnerabilities, ensuring they receive prioritized care and monitoring.

Correct answer:

During mild exercise, pulmonary gas exchange adapts to increased O2 demand and CO2 production. CO2 diffuses ~20 times faster than O2 across the alveolar-capillary membrane due to its higher solubility (0.51 vs. 0.024 ml/mmHg/L), despite a slightly higher molecular weight (44 vs. 32), per Fick's law (D ∝ solubility / √MW) making it cross easier, a true statement. Diffusing capacity (DL) for O2 is less than for CO2 normally, and while exercise increases DL for both (recruiting capillaries), CO2's advantage persists, not O2's, and molecular weight is secondary to solubility. Capillary equilibrium length shortens for O2 and CO2 as blood flow rises, but this is nuanced and not uniquely true without context. Arterial blood gases (ABGs) remain normal in healthy individuals during mild exercise (e.g., PaO2 ~100 mmHg, PaCO2 ~40 mmHg), as ventilation matches perfusion. CO2's easier diffusion is the standout truth, rooted in its physicochemical properties, critical for efficient CO2 elimination.

Correct answer:

Physiological dead space (VD) is the volume of ventilated air not participating in gas exchange, comprising anatomic dead space (conducting airways) and alveolar dead space (non-perfused alveoli). Pulmonary embolism (PE) blocks pulmonary arteries, reducing perfusion to ventilated alveoli, markedly increasing alveolar dead space and thus physiological VD (e.g., from 150 ml to 300+ ml), as large lung regions become wasted ventilation.' Atelectasis collapses alveoli, reducing ventilation and dead space, as unventilated areas don't contribute to VD. Pneumothorax collapses lung tissue, decreasing ventilated volume, not increasing dead space. Bronchoconstriction narrows airways, potentially reducing anatomic dead space slightly, and doesn't directly increase alveolar dead space unless severe hypoxia ensues. PE's perfusion defect creates the greatest VD rise, measurable via increased PaCO2-PECO2 difference, distinguishing it as the most impactful condition among these, reflecting a high V/Q mismatch.

Correct answer:

Physiological dead space (VD) is the volume of ventilated air not participating in gas exchange, comprising anatomic dead space (conducting airways) and alveolar dead space (non-perfused alveoli). Pulmonary embolism (PE) blocks pulmonary arteries, reducing perfusion to ventilated alveoli, markedly increasing alveolar dead space and thus physiological VD (e.g., from 150 ml to 300+ ml), as large lung regions become wasted ventilation.' Atelectasis collapses alveoli, reducing ventilation and dead space, as unventilated areas don't contribute to VD. Pneumothorax collapses lung tissue, decreasing ventilated volume, not increasing dead space. Bronchoconstriction narrows airways, potentially reducing anatomic dead space slightly, and doesn't directly increase alveolar dead space unless severe hypoxia ensues. PE's perfusion defect creates the greatest VD rise, measurable via increased PaCO2-PECO2 difference, distinguishing it as the most impactful condition among these, reflecting a high V/Q mismatch.

Correct answer:

The correct answer is C: An arterial blood gas (ABG) study. This is the most accurate measurement of the concentration of oxygen in the patient's blood because ABG provides direct measurement of oxygen levels, including partial pressure of oxygen (PaO2). It also gives information on other important parameters like pH and carbon dioxide levels. Arterial blood is the best representation of oxygenation status. Choice A (A capillary blood sample) may provide some information on oxygen saturation but is not as accurate as an ABG for measuring oxygen levels in the blood. Choice B (Pulse oximetry) measures oxygen saturation in peripheral blood and can give a quick estimate of oxygen levels, but it is not as accurate as an ABG for determining the actual oxygen concentration in the blood. Choice D (A complete blood count) does not provide direct information on oxygen levels in the blood, as it mainly focuses on the cellular components of blood such as red blood cells, white blood cells, and

Correct answer:

The PAO2-PaO2 gradient measures the difference between alveolar oxygen (PAO2) and arterial oxygen (PaO2), normally small (~5-10 mmHg) due to efficient diffusion. In pulmonary fibrosis, thickened alveolar walls from scarring impair O2 diffusion, lowering PaO2 (e.g., 60 mmHg) while PAO2 (calculated via the alveolar gas equation, ~100 mmHg at sea level) remains closer to normal, widening the gradient (e.g., 40 mmHg). During exercise in a normal person, increased cardiac output and ventilation match perfusion, keeping the gradient minimal despite higher O2 demand. Anemia reduces oxygen-carrying capacity (low hemoglobin), not diffusion, so PaO2 approximates PAO2, maintaining a normal gradient. At 5000 meters, low atmospheric PO2 reduces both PAO2 and PaO2 proportionately (e.g., PAO2 ~50 mmHg, PaO2 ~45 mmHg), keeping the gradient small. Pulmonary fibrosis uniquely disrupts diffusion, causing the largest gradient, as fibrotic barriers hinder O2 transfer more than ventilation or perfusion issues.

Correct answer:

The PAO2-PaO2 gradient measures the difference between alveolar oxygen (PAO2) and arterial oxygen (PaO2), normally small (~5-10 mmHg) due to efficient diffusion. In pulmonary fibrosis, thickened alveolar walls from scarring impair O2 diffusion, lowering PaO2 (e.g., 60 mmHg) while PAO2 (calculated via the alveolar gas equation, ~100 mmHg at sea level) remains closer to normal, widening the gradient (e.g., 40 mmHg). During exercise in a normal person, increased cardiac output and ventilation match perfusion, keeping the gradient minimal despite higher O2 demand. Anemia reduces oxygen-carrying capacity (low hemoglobin), not diffusion, so PaO2 approximates PAO2, maintaining a normal gradient. At 5000 meters, low atmospheric PO2 reduces both PAO2 and PaO2 proportionately (e.g., PAO2 ~50 mmHg, PaO2 ~45 mmHg), keeping the gradient small. Pulmonary fibrosis uniquely disrupts diffusion, causing the largest gradient, as fibrotic barriers hinder O2 transfer more than ventilation or perfusion issues.

Correct answer:

During mild exercise, pulmonary gas exchange adapts to increased O2 demand and CO2 production. CO2 diffuses ~20 times faster than O2 across the alveolar-capillary membrane due to its higher solubility (0.51 vs. 0.024 ml/mmHg/L), despite a slightly higher molecular weight (44 vs. 32), per Fick's law (D ∝ solubility / √MW) making it cross easier, a true statement. Diffusing capacity (DL) for O2 is less than for CO2 normally, and while exercise increases DL for both (recruiting capillaries), CO2's advantage persists, not O2's, and molecular weight is secondary to solubility. Capillary equilibrium length shortens for O2 and CO2 as blood flow rises, but this is nuanced and not uniquely true without context. Arterial blood gases (ABGs) remain normal in healthy individuals during mild exercise (e.g., PaO2 ~100 mmHg, PaCO2 ~40 mmHg), as ventilation matches perfusion. CO2's easier diffusion is the standout truth, rooted in its physicochemical properties, critical for efficient CO2 elimination.