Respiratory Therapy Flashcards

A sputum Gram stain shows gram-positive diplococci. The most likely pathogen is:

Answer: Streptococcus pneumoniae

Gram-positive diplococci (paired cocci) are the hallmark morphology of Streptococcus pneumoniae, the most common bacterial pneumonia pathogen.

Which parameter BEST reflects a patient's work of breathing and respiratory muscle load during weaning?

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.

A patient with cystic fibrosis benefits MOST from which airway clearance technique using an oscillating PEP device?

Answer: Flutter valve therapy

Flutter (oscillating PEP) devices generate high-frequency oscillations that loosen mucus and maintain airway patency, making them effective in CF.

In high-frequency oscillatory ventilation (HFOV), oxygenation is primarily controlled by adjusting:

Answer: Mean airway pressure (MAP)

In HFOV, mean airway pressure (MAP) determines lung volume and alveolar recruitment, which is the primary determinant of oxygenation.

Which finding on a chest X-ray is MOST consistent with a right pleural effusion?

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.

Hypoxic pulmonary vasoconstriction (HPV) serves what physiological purpose?

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.

The Fick equation for cardiac output requires which four variables?

Answer: VO2, Hgb, SaO2, SvO2

The Fick method calculates CO = VO2 / (CaO2 − CvO2), requiring oxygen consumption (VO2), hemoglobin, and arterial/venous saturations.