[Measurement by mass spectrometry of oxygen consumption and carbon dioxide production in mechanically ventilated patients].

The authors present a technique of VO2 and VCO2 measurements by a non invasive method in mechanically ventilated patients. Inspirated and expirated gas are sampled respectively in the inspiratory limb of the patient's breathing circuit and in a mixing chamber. Gas samples are analysed by mass spectrometry in the laboratory. Expiratory flow rate is determined by the ventilator flowmeter. To evaluate this procedure the authors have studied the stability of the inspirated and expirated gas samples and the reproductibility of measurements. In a patient with respiratory and haemodynamic stable status this method measures VO2 within 8,2% and VCO2 within 7%.