Potential metabolic causes for a respiratory quotient (RQ) greater than 1 include all of the following EXCEPT

Potential metabolic causes for a respiratory quotient (RQ) greater than 1 include all of the following EXCEPT

• A. Overfeeding
• B. Hypoventilation
• C. Excess CO2 production
• D. Provision of excess sodium bicarbonate

Answer: (B)

RQ equals the amount of CO2 produced divided by the amount of O2 consumed (VCO2/VO2). Values above 1 occur when CO2 production exceeds what would be expected from substrate oxidation alone, typically due to metabolic processes that generate extra CO2. Overfeeding—especially carbohydrate overfeeding—drives more carbohydrate oxidation and processes like lipogenesis that can raise CO2 output, pushing RQ above 1. Providing excess sodium bicarbonate causes buffering of acids produced during metabolism, releasing additional CO2 and increasing the RQ. Excess CO2 production from metabolic activity likewise raises the ratio. Hypoventilation is a ventilatory issue that alters CO2 elimination rather than a metabolic process that changes substrate usage; it does not cause a true metabolic RQ rise.

RQ equals the amount of CO2 produced divided by the amount of O2 consumed (VCO2/VO2). Values above 1 occur when CO2 production exceeds what would be expected from substrate oxidation alone, typically due to metabolic processes that generate extra CO2. Overfeeding—especially carbohydrate overfeeding—drives more carbohydrate oxidation and processes like lipogenesis that can raise CO2 output, pushing RQ above 1. Providing excess sodium bicarbonate causes buffering of acids produced during metabolism, releasing additional CO2 and increasing the RQ. Excess CO2 production from metabolic activity likewise raises the ratio. Hypoventilation is a ventilatory issue that alters CO2 elimination rather than a metabolic process that changes substrate usage; it does not cause a true metabolic RQ rise.