Reliability of the Partial CO_2 Rebreathing Technique for Measurement of Cardiac Output

摘要

The partial CO_2 rebreathing technique has been suggested to accurately estimate cardiac output (Q_t) even in the presence of lung injury. Using a computer-based gas exchange mesurement system and graphical and textual programming languages, we evaluated the reliability of this noninvasive technique for measurement of cardiac output in the setting of lung atelectasis and lung injury. The error of estimating Q_t with this method correlates with the right to leftrnintrapulmonary shunt fraction (Q_s / Q_t). We conclude that this technique is not reliable in the setting of lung injury, but is useful for the mechanically ventilated patient with normalrnQ_s/Q_t.