A 24-year-old woman with type 1 diabetes presents with blood glucose of 480 mg/dL, pH 7.12, and deep rapid respirations. The respiratory pattern she is exhibiting serves which physiological purpose?
- A To increase carbon dioxide retention and buffer hydrogen ions intracellularly
- B To blow off carbon dioxide and drive the bicarbonate buffer equation toward consumption of hydrogen ions ✓
- C To increase oxygen delivery by raising alveolar oxygen tension
- D To stimulate the medullary chemoreceptors and restore normal pH through renal compensation
Correct answer: B. To blow off carbon dioxide and drive the bicarbonate buffer equation toward consumption of hydrogen ions
Explanation
In ketoacidosis the low pH stimulates peripheral chemoreceptors, producing deep rapid Kussmaul breathing. By eliminating carbon dioxide, ventilation pulls the bicarbonate buffer equation to the right, consuming hydrogen ions and partially restoring pH. Carbon dioxide retention would worsen acidosis, and renal compensation is far too slow for an acute acid load. The pattern is driven primarily by arterial hydrogen ion concentration acting on carotid bodies, not by oxygen or medullary chemoreceptors.
Reference: Ganong Review of Medical Physiology, 26th ed.
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Written and medically reviewed by the StethoPrep medical team.