Lactate in shock — FRCA Primary MCQ

Correct answer: E — Reduced haemoglobin lowers arterial oxygen content

Tissue hypoperfusion can cause anaerobic metabolism and lactate production. Small myelinated fibres block relatively early is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Ventilation of poorly perfused alveoli increases dead space is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Acidosis shifts the oxyhaemoglobin curve right is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. High oxygen consumption and low FRC shorten safe apnoea time is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physiology, the correct answer is usually the variable that best explains the observed change in the anaesthetised patient.

Reference: West's Respiratory Physiology; Ganong Review of Medical Physiology; Primary FRCA textbooks