RRT Clinical Concepts Flashcards

A patient with status asthmaticus is intubated. Dynamic hyperinflation is suspected. Which intervention directly addresses auto-PEEP?

Answer: Increase inspiratory flow rate to allow longer expiratory time

Increasing inspiratory flow rate shortens inspiratory time, thereby lengthening expiratory time and reducing air trapping and auto-PEEP.

Which condition is characterized by a diffusion defect rather than a V/Q mismatch as the primary mechanism of hypoxemia?

Answer: Pulmonary fibrosis

Pulmonary fibrosis thickens the alveolar-capillary membrane, impairing oxygen diffusion across it.

A COPD patient has chronic hypercapnia with pH 7.38, PaCO2 58 mmHg, HCO3 33 mEq/L. Administering high-flow oxygen may cause hypoventilation because:

Answer: The hypoxic drive is abolished

In some COPD patients chronically reliant on hypoxic drive, supplemental oxygen can blunt the stimulus to breathe, causing hypoventilation.

Which hemodynamic finding is most consistent with cor pulmonale?

Answer: Elevated right ventricular pressure with normal PAWP

Cor pulmonale causes right heart strain from pulmonary hypertension, elevating RV pressure while the left heart and PAWP remain normal.

A patient post-lobectomy develops subcutaneous emphysema and a persistent air leak from the chest tube. The most likely cause is:

Answer: Bronchopleural fistula

A bronchopleural fistula is an abnormal communication between the bronchial tree and the pleural space, causing persistent air leak.

Which parameter should be monitored to assess adequacy of alveolar ventilation in a mechanically ventilated patient?

Answer: PaCO2

PaCO2 is the direct measure of alveolar ventilation; rising PaCO2 indicates hypoventilation.

The Hering-Breuer reflex limits tidal volume by:

Answer: Stretch receptor activation in the lung

Pulmonary stretch receptors activated by lung inflation send signals via the vagus nerve to terminate inspiration, preventing overdistension.