The ICALIC Accuracy Validation in Geneva Study

University Hospitals (UH)

Status: Unknown

Conditions: Critical Illness

Treatments: Other: Indirect calorimetry

Study type: Observational

Funder types: Other

Identifiers

NCT02790697

15-137_Addendum

Details and patient eligibility

About

This study aims at validating the accuracy of the new indirect calorimeter (Q-NRG, COSMED, Italy), developed for the ICALIC multicenter study. The validation of accuracy will only be conducted in Geneva center.

The measurements made with the new calorimeter will be compared to the measurements by the mixing chamber method using a mass spectrometer (MAX300-LG, Extrel, USA) for gas composition analysis.

Full description

Indirect calorimetry is a method to measure energy expenditure of human subjects by analyzing patient breath gas to measure the amount (volume) of oxygen consumption (VO2) and CO2 production (VCO2). Energy expenditure is calculated by the Weir's equation using the measured VO2 and VCO2 values.

The new calorimeter is equipped with a disposable in-line pneumotach flowmeter, which measures the flow of exhaled gas of patients directly within the mechanical ventilator circuit. It also samples small amount of inhaled and exhaled gas to measure the inhaled and exhaled O2 and CO2 compositions. The new dynamic micro-mixing chamber technique is used to meaure VO2 and VCO2 to derive the energy expenditure.

The mass spectrometer measures the inhaled and exhaled gas compositions. The mass spectrometer samples inhaled gas from the mechanical ventilator circuit. A mixing chamber system is used to collect the expired gas from the outlet of the mechanical ventilator. The collected gas is measured for the second time after diluting with a constant flow of ambient air, which is monitored by an independent mass flow meter. The volume of the expired gas is calculated by comparison of the concentrations of exhaled gas before and after the dilution. The measurements will be used to calculate the VO2 and VCO2 to derive the energy expenditure.

Enrollment: 30 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Mechanically ventilated adult ICU patients

Exclusion criteria

• Fraction of inhaled oxygen (FIO2) > 70%
• Positive end expiratory pressure (PEEP) >10cmH2O
• Peak ventilatory pressure > 30cmH2O
• Presence of air leaks from thoracic drain tube
• Changes in vasoactive agent dose (>20%, <1 hr before and/or during IC)
• Agitation or change in sedative dose (>20%, <1 hr before and/or during IC)
• Change in body temperature (>0.5°C, <1 hr before and/or during IC)
• Expected duration of ICU stay < 24 hours
• Expected survival of the patient < 24 hours

Trial design

30 participants in 1 patient group

Mechanically ventilated ICU patient

Description:

Indirect calorimetry measurements will be conducted using the new calorimeter and the mass spectrometer system at the same time for all enrolled patients.

Treatment:

Other: Indirect calorimetry