Increased pulmonary platelet sequestration due to infusion of cold saline during extracorporeal circulation

We have previously documented that neutrophils (polymorphonuclear leukocytes) aggregate in the lungs 10-15 min after the start of dialysis. The aim of the present study was to investigate the corresponding platelet reaction and evaluate the effect of prewarmed priming solution on this reaction. The animals were divided into two groups, each consisting of 6 pigs. In group 1 the priming solution was prewarmed to 36-38 degrees C whereas it was maintained at room temperature in group 2. Platelets were selectively labelled with 111In-oxine. The activity over the lung was followed dynamically with a gamma camera and already after 2 min a significant difference in platelet sequestration showed between the groups. A significant increase in pulmonary vascular resistance was noted in group 2, but not in group 1. In conclusion, platelet aggregation occurs early on during dialysis in this model. The results also indicate that prewarming the priming solution attenuates the pulmonary platelet sequestration and also seems to decrease the changes in central hemodynamics.