No participation of centers outside Switzerland because of difficulty in recruiting during a Covid pandemic.

Clinicians need to measure energy expenditure (EE) by indirect calorimetry (IC) to optimize nutritional support for a better clinical outcome, especially in patients with chronic conditions or with high risk of under- and over- feeding. However, IC is rarely used in clinical routine because the devices currently on the market are of tedious use, imprecise and expensive. An easy-to-use, accurate and inexpensive IC device (Q-NRG® CE marking n°MED 9811) has been developed to meet specifications made by and for clinicians. The ease of use of this new IC device has been first evaluated in mechanical ventilation mode. This second phase aims at evaluating the ease of use, the stability and the feasibility of the measurements with this new IC device in canopy and face mask modes for spontaneously breathing adult patients.

This study aims at evaluating the ease of use, the stability and the feasibility of EE measurements with the new IC device in spontaneously breathing adult patients with malnutrition, cancer, surgery or haemodialysis, using the canopy and face mask modes.

Patient data will be obtained from the medical records before EE measurement. EE measurement will be performed sequentially with the Q-NRG® and the IC device currently used in each study center. Patient data input, calibration, installation of face mask or canopy hood on the patient, and EE measurement recording will be performed according to the procedure stated in their respective user manual. Time needed to perform EE will be calculated afterwards from the time the IC device is turned on to EE measurement reaches a steady state with a variation ≤10%.

In a subset of 15 subjects, accuracy of gas composition (O2 and CO2) measurement by the Q-NRG® will be assessed by comparison with the reference method consisting in a mass spectrometer.

Inclusion Criteria:

All spontaneously breathing adult patients (≥ 18 years) referred to the Nutrition Unit in the context of malnutrition, cancer, surgery or haemodialysis.

Exclusion Criteria:

1. < 18 years
2. Intolerance or phobia to canopy or face mask
3. Physical agitation or activity (< 1hr before EE measurement)
4. Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant.

Spontaneously breathing adult patients with malnutrition, cancer, surgery or haemodialysis.