The cardiorespiratory impairment in cirrhosis and sepsis. An experimental interpretation using octopamine infusion.

: The effects of octopamine on systemic and pulmonary circulation and on respiratory parameters have been studied in ten O2 100% breathing pigs. A rise in cardiac index (CI) due to an increase in the dynamics of the left ventricle and a progressive hypoxemia, notwithstanding the hyperventilation, was found. The decrease in arterial O2 tension was due to a rise in the pulmonary shunt fraction (QS/QT). The statistical analysis of cardiorespiratory parameters demonstrated that the high flow state linked with a non-Starling mechanism was the causing factor of a ventilation: perfusion ratio (VA/QT) decrease, which led to the rise in QS/QT. Also, a decrease in the lung compliance simultaneous to the increased blood flow was observed. It is suggested that octopamine may play a role in the pathogenesis of the cardiorespiratory hemodynamic impairment of cirrhosis and sepsis where high levels of this false neurotransmitter were observed.