Which type of shock results from dysfunction in the body's ability to utilize oxygen, such as issues with diffusion, transport by hemoglobin, or cellular use (metabolic or respiratory shock)?

• A. Anaphylactic shock
• B. Metabolic or respiratory shock
• C. Cardiogenic shock
• D. Obstructive shock

Answer: (B)

The key idea is a failure of cells to use oxygen properly, not just a shortage of oxygen delivery. Metabolic or respiratory shock describes situations where diffusion, transport by hemoglobin, or cellular use of oxygen is impaired, so tissues become hypoxic even if blood flow and oxygen in the blood are present. This includes problems with oxygen moving from the lungs into the blood (diffusion), oxygen being carried to tissues by hemoglobin (transport), or the cells’ ability to extract and use oxygen (cellular metabolism). Examples include diffusion issues from lung problems, anemia or toxic gases like carbon monoxide or methemoglobinemia affecting transport, and poisons like cyanide that block cellular use. In contrast, anaphylactic shock is a distributive problem with widespread vasodilation and capillary leak; cardiogenic shock arises from the heart failing to pump effectively; obstructive shock involves a physical blockage to blood flow. Therefore, dysfunction in oxygen utilization at any step points to metabolic or respiratory shock.