________ may result from rapid shallow respirations in obese animals under anesthesia.

________ may result from rapid shallow respirations in obese animals under anesthesia.

• A. Hypoxemia
• B. Hypercapnia
• C. Hypocapnia
• D. Hyperoxia

Answer: (B)

Rapid shallow respirations reduce effective ventilation because tidal volume falls while dead space ventilation remains constant. In obese animals, already having reduced functional residual capacity and tendency for airway closure, this pattern further decreases alveolar ventilation, leading to retention of carbon dioxide. The result is hypercapnia, with a rise in arterial CO2 and possible respiratory acidosis. Hypoxemia can occur in obesity due to atelectasis and V/Q mismatch, but the direct consequence of rapid shallow breathing is CO2 retention rather than a primary drop in oxygen. Hypocapnia would come from blowing off CO2 with excessive ventilation, which is not the scenario here, and hyperoxia refers to high oxygen levels, not the ventilation pattern itself.

Rapid shallow respirations reduce effective ventilation because tidal volume falls while dead space ventilation remains constant. In obese animals, already having reduced functional residual capacity and tendency for airway closure, this pattern further decreases alveolar ventilation, leading to retention of carbon dioxide. The result is hypercapnia, with a rise in arterial CO2 and possible respiratory acidosis.

Hypoxemia can occur in obesity due to atelectasis and V/Q mismatch, but the direct consequence of rapid shallow breathing is CO2 retention rather than a primary drop in oxygen. Hypocapnia would come from blowing off CO2 with excessive ventilation, which is not the scenario here, and hyperoxia refers to high oxygen levels, not the ventilation pattern itself.