Monitoring of Pulmonary Capillary Blood Flow and Alveolar Dead Space Using the Combined Methods of Volumetric Capnography and “Partial CO2 Rebreathing” (NiCO2)
Data available in all operating theaters and intensive care units make it possible to obtain important information about the adequacy of the ventilation perfusion ratio (V/Q). This ratio, which is normally 0.8, decreases and increases in two specific conditions. It decreases in the case of poorly ventilated but perfused alveoli (increased shunt QS/QT) and it increases with well-ventilated but poorly perfused alveoli (increased alveolar dead space VD ALV). In both of these cases, it is difficult for the pulmonary capillary to eliminate CO2, in the first case due to inadequate ventilation and in the second because of inadequate perfusion. Thus, arterial CO2 (paCO2) increases and alveolar pCO2 (pet CO2 of traditional capnography) decreases in both situations.
KeywordsCardiac Output Acute Respiratory Distress Syndrome Artificial Ventilation Alveolar Ventilation Alveolar Dead Space
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- 3.Nunn JF (1993) Applied respiratory physiology, 4th edn Butterworth, OxfordGoogle Scholar