Haemodynamic and Metabolic Evaluations by Rebreathing Methods
Cardiac output (CO) is a key parameter to assess the haemodynamic status, the cardiac performance and the therapeutic management in critical patients. In anaesthesia and intensive care practice, the methods most often used to measure CO are the classical thermodilution by a pulmonary artery catheter and the transpulmonary thermodilution by a femoral artery catheter [1, 2]. These methods are invasive and require a time period for catheter positioning. Therefore, they can not be used in low-risk patients and in emergency wards. Trans-esophageal echo-Doppler, even if less invasive, is expensive and requires high skilled personnel . To solve the above limitations, new methods have been proposed to measure CO at the bedside. Rebreathing methods seem to be ideal in mechanically ventilated patients because they are non-invasive, continuous, not time consuming and inexpensive. The physiological basis, the different techniques and the clinical application of rebreathing methods will be discussed in the following paragraphs.
KeywordsSingle Breath Transpulmonary Thermodilution Mixed Venous Blood Alveolar Dead Space Rebreathing Method
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