A 28-year-old woman from Delhi presents to the emergency department with severe vomiting and abdominal pain following food poisoning. On examination, she is tachypneic (RR 28/min) and appears anxious. Arterial blood gas shows: pH 7.52, PaCO₂ 28 mmHg, HCO₃⁻ 22 mEq/L, PaO₂ 95 mmHg. Her hemoglobin is 12 g/dL and oxygen saturation is 98% on room air. Despite adequate oxygenation and normal hemoglobin, her tissues appear to be extracting oxygen poorly. Which of the following best explains the impaired oxygen delivery to tissues in this patient?