Problems Associated with Clinical Determination of Pulmonary Shunting

  • H. M. Lohbrunner
  • K. J. Falke
Conference paper


A disturbance of pulmonary gas exchange results in hypoxaemia and hypercarbia. Given a stable cardiac output and a known FiO2, it is possible to explain changes in arterial PO2 and PCO2 by mismatch of alveolar ventilation to pulmonary perfusion or disturbance of the distribution of the alveolar ventilation to perfusion ratio (VA/Q). The normal healthy lung consists of more than 300 million alveoli which all receive the same inspiratory gas and mixed venous blood. Nevertheless the composition of intraalveolar and endcapillary partial pressures of O2, CO2 and N2 differ between various areas of the lung because the partial pressures in the alveoli (PA) depend upon the VA/Q.


Adult Respiratory Distress Syndrome Alveolar Ventilation Pulmonary Shunting Mixed Venous Blood Intrapulmonary Shunt 
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Copyright information

© Springer-Verlag Italia 1999

Authors and Affiliations

  • H. M. Lohbrunner
    • 1
  • K. J. Falke
    • 1
  1. 1.Dept. of Anaesthesiology and Intensive CareHumboldt University HospitalBerlinGermany

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