RRT Respiratory Therapy 4 — Questions and Answers
Question 1: A sputum Gram stain shows gram-positive diplococci. The most likely pathogen is:
- Staphylococcus aureus
- Streptococcus pneumoniae (Correct answer)
- Klebsiella pneumoniae
- Haemophilus influenzae
Correct answer: Streptococcus pneumoniae
Gram-positive diplococci (paired cocci) are the hallmark morphology of Streptococcus pneumoniae, the most common bacterial pneumonia pathogen.
Question 2: Which parameter BEST reflects a patient's work of breathing and respiratory muscle load during weaning?
- Rapid shallow breathing index (RSBI) (Correct answer)
- PaO2/FiO2 ratio
- Peak inspiratory pressure
- Static compliance
Correct answer: Rapid shallow breathing index (RSBI)
RSBI (f/VT) > 105 breaths/min/L predicts weaning failure by reflecting the combination of high rate and low tidal volume from respiratory muscle fatigue.
Question 3: A patient with cystic fibrosis benefits MOST from which airway clearance technique using an oscillating PEP device?
- Postural drainage and percussion
- Flutter valve therapy (Correct answer)
- Incentive spirometry
- CPAP therapy
Correct answer: Flutter valve therapy
Flutter (oscillating PEP) devices generate high-frequency oscillations that loosen mucus and maintain airway patency, making them effective in CF.
Question 4: In high-frequency oscillatory ventilation (HFOV), oxygenation is primarily controlled by adjusting:
- Frequency (Hz)
- Amplitude (ΔP)
- Mean airway pressure (MAP) (Correct answer)
- Inspiratory time percentage
Correct answer: Mean airway pressure (MAP)
In HFOV, mean airway pressure (MAP) determines lung volume and alveolar recruitment, which is the primary determinant of oxygenation.
Question 5: Which finding on a chest X-ray is MOST consistent with a right pleural effusion?
- Hyperinflation with flattened diaphragm
- Blunting of the right costophrenic angle (Correct answer)
- Air bronchograms in the right lower lobe
- Bilateral perihilar infiltrates
Correct answer: Blunting of the right costophrenic angle
Blunting of the costophrenic angle occurs when at least 150–200 mL of fluid accumulates in the pleural space.
Question 6: Hypoxic pulmonary vasoconstriction (HPV) serves what physiological purpose?
- Increases cardiac output during exercise
- Diverts blood away from poorly ventilated lung regions (Correct answer)
- Reduces systemic vascular resistance
- Promotes surfactant production
Correct answer: Diverts blood away from poorly ventilated lung regions
HPV constricts pulmonary arterioles in hypoxic lung units, redirecting blood to better-ventilated regions to optimize V/Q matching.
Question 7: The Fick equation for cardiac output requires which four variables?
- HR, SV, PaO2, PvO2
- VO2, Hgb, SaO2, SvO2 (Correct answer)
- CO, Hgb, CaO2, CvO2
- MAP, CVP, SVR, HR
Correct answer: VO2, Hgb, SaO2, SvO2
The Fick method calculates CO = VO2 / (CaO2 − CvO2), requiring oxygen consumption (VO2), hemoglobin, and arterial/venous saturations.
RRT Respiratory Therapy 4
A sputum Gram stain shows gram-positive diplococci.
The most likely pathogen is: