How to interpret and apply the results of indirect calorimetry studies: A case-based tutorial

Area of Science:

• Clinical Nutrition
• Critical Care Medicine
• Metabolic Monitoring

Background:

• Growing evidence supports individualized energy targets via indirect calorimetry (IC) for improved patient outcomes.
• New, user-friendly IC devices facilitate personalized nutrition care.
• IC principles are applicable across devices for tailoring nutrition prescriptions.

Purpose of the Study:

• To share knowledge and expertise on individualizing nutrition care using indirect calorimetry.
• To demonstrate the clinical application of IC in intubated and spontaneously breathing adult patients.
• To guide the use of measured energy expenditure (mEE) and respiratory quotient (RQ) for nutrition prescription.

Main Methods:

• Tutorial format focusing on a contemporary indirect calorimetry device.
• Application of IC principles across various patient populations, from critical illness to outpatients.
• Case studies illustrating the use of mEE and RQ to adapt nutrition prescriptions.

Main Results:

• Measured energy expenditure (mEE) and respiratory quotient (RQ) effectively guide nutrition adjustments.
• RQ serves as a marker for overfeeding or underfeeding and indicates substrate utilization.
• IC devices function as metabolic monitors when combined with clinical observations and biomarkers.

Conclusions:

• Indirect calorimetry is a valuable tool for individualizing nutrition therapy in diverse adult patient groups.
• Understanding mEE and RQ variations is crucial for optimizing nutrition support and assessing metabolic status.
• The tutorial highlights IC's utility while acknowledging its limitations and suggesting alternatives.