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Oxyhaemoglobin dissociation curve right shift — FRCA Primary MCQ

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EasyPhysiologyOxyhaemoglobin dissociation curve right shiftFRCA Primary

A septic patient in theatre is febrile and acidotic. The anaesthetist notes that tissue unloading of oxygen may be facilitated. Which change in the oxyhaemoglobin dissociation curve is expected?

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Correct answer: A — Right shift from acidosis and pyrexia

Acidosis, increased PaCO2, pyrexia and increased 2,3-DPG shift the oxyhaemoglobin dissociation curve to the right, increasing P50 and facilitating tissue unloading. A left shift would increase affinity and impair unloading. Reduced 2,3-DPG shifts the curve left. The Bohr effect is highly relevant during sepsis and exercise.

Reference: West Respiratory Physiology; Ganong Review of Medical Physiology