American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Failure to wean off a ventilator may suggest which nutritional deficiency?

1. Thiamine deficiency

2. Cobalamin deficiency

3. Phosphate deficiency

4. Ascorbic acid deficiency

The correct answer is: Phosphate deficiency

Failure to wean a patient off a ventilator can suggest a deficiency in phosphate. Phosphate plays a critical role in energy metabolism, cellular function, and the synthesis of ATP, which is essential for muscle function, including the respiratory muscles. Inadequate phosphate levels can lead to muscle weakness and respiratory failure due to impaired neuromuscular function. Patients with hypophosphatemia may present with diminished muscle strength, which can affect their ability to breathe independently and to initiate or sustain the breath against the resistance of ventilatory support. Therefore, the associated respiratory muscle weakness from phosphate deficiency could be a significant factor in the inability to wean off mechanical ventilation. While thiamine, cobalamin, and ascorbic acid are important for various physiological functions, deficits in these nutrients do not typically manifest specifically as weaknesses in respiratory muscle function leading to challenges in weaning from ventilatory support in the same way that phosphate deficiency does.