A 55-year-old male patient who is febrile has failed multiple weaning trials following an exacerbation of asthma. The patient is receiving 2,000 kcal/day by orogastric tube. A metabolic study by indirect calorimetry was performed to determine appropriate feeding. Which of the following MOST likely has a direct relationship to the failed weaning trials?
1) CO₂ production
2) Respiratory quotient
3) Oxygen consumption
4) Resting energy expenditure