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.