Central hemodynamics and pulmonary ventilation after trauma: effect of portacaval transposition

Immediate reaction to traumatic shock involves, among other factors, trapping of platelets in the lungs. It has previously been shown that this trapping is associated with an increase in pulmonary vascular resistance (PVR). To elucidate whether this increase in PVR was due to cellular sequestration or other factors, we performed a portacaval transposition in a group of pigs (n = 9), making the liver the first receiving capillary bed for blood from the lower extremities. One week later, these animals and a control group (n = 6) were subjected to a standardized soft tissue trauma to the hind limbs. Following trauma, there was an immediate increase in PVR in the control group but not in the operated animals. This increase in PVR was accompanied by a fall in alveolar ventilation that was significantly lower in the control group than in the operated animals. There were no differences in blood gases, probably because of high FiO2 during the experiment. Our findings indicate that the early response in pulmonary circulation following trauma is due to cellular sequestration from the trauma sites.