RRT RRT MCQ 2 — Questions and Answers
Question 1: A patient with ARDS has a PaO2 of 55 mmHg on FiO2 0.80. Which ventilator strategy is MOST appropriate?
- Increase tidal volume to 10 mL/kg IBW
- Apply permissive hypercapnia with low tidal volumes (Correct answer)
- Decrease PEEP to reduce barotrauma risk
- Switch to pressure control with high peak pressures
Correct answer: Apply permissive hypercapnia with low tidal volumes
Lung-protective ventilation in ARDS uses low tidal volumes (6 mL/kg IBW) and accepts permissive hypercapnia to minimize ventilator-induced lung injury.
Question 2: Which acid-base disorder is associated with hypokalemia and metabolic alkalosis?
- Renal tubular acidosis
- Diuretic use causing chloride depletion (Correct answer)
- Diabetic ketoacidosis
- Lactic acidosis from sepsis
Correct answer: Diuretic use causing chloride depletion
Loop and thiazide diuretics cause loss of chloride, hydrogen, and potassium ions, resulting in hypochloremic hypokalemic metabolic alkalosis.
Question 3: When performing a helium-oxygen (heliox) therapy, which condition benefits MOST?
- Diffuse alveolar damage
- Upper airway obstruction causing turbulent flow (Correct answer)
- Pulmonary fibrosis
- Pneumothorax
Correct answer: Upper airway obstruction causing turbulent flow
Heliox reduces gas density, converting turbulent to laminar flow, which is most beneficial in upper airway obstructions such as croup or post-extubation stridor.
Question 4: A mechanically ventilated patient has sudden increase in peak airway pressure with no change in plateau pressure. The MOST likely cause is:
- Pneumothorax
- Pulmonary edema
- Endotracheal tube obstruction
- Bronchospasm (Correct answer)
Correct answer: Bronchospasm
An increase in peak pressure with unchanged plateau pressure indicates increased airway resistance, most commonly from bronchospasm or secretion buildup in the airway.
Question 5: A patient has PaO2 60 mmHg, PaCO2 50 mmHg, pH 7.32, HCO3 25 mEq/L on room air. What is the MOST likely diagnosis?
- Acute metabolic acidosis with compensation
- Acute respiratory acidosis without compensation (Correct answer)
- Chronic respiratory acidosis with compensation
- Mixed respiratory and metabolic acidosis
Correct answer: Acute respiratory acidosis without compensation
A normal bicarbonate with low pH and elevated PaCO2 indicates acute respiratory acidosis with no renal compensation yet.
Question 6: Which chest X-ray finding is MOST consistent with a right-sided pleural effusion?
- Increased opacity at the right apex with tracheal deviation
- Blunting of the right costophrenic angle with opacification (Correct answer)
- Air-fluid level at the right base with surrounding consolidation
- Hyperlucency of the right hemithorax
Correct answer: Blunting of the right costophrenic angle with opacification
Pleural effusion typically presents as blunting of the costophrenic angle and a meniscus sign on upright chest X-ray.
Question 7: During a 6-minute walk test, a patient's SpO2 drops from 97% to 84%. This finding indicates:
- Normal physiologic response to exercise
- Significant exercise-induced desaturation requiring supplemental oxygen evaluation (Correct answer)
- Equipment artifact that should be disregarded
- Mild hypoxemia not clinically significant
Correct answer: Significant exercise-induced desaturation requiring supplemental oxygen evaluation
A drop in SpO2 to below 88–90% during exertion is significant exercise-induced desaturation that typically warrants supplemental oxygen therapy prescription.
RRT RRT MCQ 2
A patient with ARDS has a PaO2 of 55 mmHg on FiO2 0.80.
Which ventilator strategy is MOST appropriate?