Plastic particle migration during intravenous infusion assisted by a peristaltic finger pump in an animal model.

The contamination of intravenously administered fluid with foreign material has always been of major concern, but the in-vivo impact of silicone embolisation from administration of fluid via a peristaltic finger pump (PFP) has not previously been assessed. To determine whether silicone particles enter the lungs and to review the histological response, 10 rabbits received an IV infusion of 0.9% saline at 10 ml/kg per hour over a 72-h period, via an IVAC 591 PFP. The lungs were analysed for silicone particles with scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA). These results were compared with a control group of non-infused animals. Silicone particles were found in 8 of 10 animals in the experimental group and in 2 of 9 control animals, indicating that silicone particles are dislodged during pump-assisted IV infusions. The difference between the control and infused animals was statistically significant using Fisher's exact test (P = 0.023). However, silicone plastic particles in control animals suggest that there is also environmental exposure to silicone in addition to those particles that come from a therapeutic source. The additional finding of elemental silicon (which is one of the constituents of silicone plastic) in both infused and control animals in which silicone plastic was not found indicates that not all elemental silicon in animals reflects the presence of silicone plastic. The clinical significance of each of these two findings is yet to be determined.

The development of a pig model to study fetal vesico-ureteric reflux.

OBJECTIVE: To develop a surgical protocol to induce vesico-ureteric reflux (VUR) in utero by ablating the ureteric tunnel in a fetal pig model. MATERIALS AND METHODS: Fetal surgery was conducted on nine sows, which were divided into three groups according to changes in the surgical protocol. Sows in groups 2 and 3 received different anaesthetics and antibiotics, and the operating theatre temperature was increased. In all cases, the intramural part of the ureter was unroofed in the fetuses, which were then returned to the uterus. Upon delivery, cystograms were taken in the male piglets, and the urinary tracts removed for anatomical and histological examination. RESULTS: All three sows in group 1 delivered healthy piglets, but the fetuses that had undergone surgery were mummified. In group 2 the animals survived the fetal intervention, as shown by ultrasonography after surgery, but the four sows aborted spontaneously within a week. In group 3, both sows delivered normally developed piglets, three of which had undergone ablation of the ureteric tunnel. VUR was present only in those renal units in which the ureteric tunnel was ablated, and this was associated with hydronephrosis, dilatation of the ureters and thinning of the renal parenchyma on gross pathological examination. CONCLUSIONS: The fetal pig model of VUR not only appears to be feasible, but with similarities in renal anatomy and physiology also seems to be ideal for investigating fetal VUR.

Ureteric tunnel incision in the fetal pig: a model for non-obstructive prenatal vesicoureteric reflux.

The understanding of vesicoureteric reflux (VUR) continues to improve, particularly as the renal tract can now be assessed prenatally. To further study the evolution of fetal renal changes, we studied two neonatal piglets that had undergone midgestation ureteric tunnel ablation. Dilatation of the pelvicalyceal system was seen radiologically and macroscopically in all three kidneys into which VUR had been created. Despite the study being marred by poor fetal survival, the results indicate that the model should be developed further to explore what appears to be an interrelationship between VUR and renal parenchymal changes in utero.