Potential effects of infused particles in paediatric intensive care patients

Introduction

As a part of a clinical trial to evaluate the potential benefits of inline filtration on reducing major complications of paediatric ICU (PICU) patients (Clinical Trials.gov ID NCT 00209768), we examined the physical aspects and chemical composition of particles captured by inline microfilters. Additionally we investigated the inflammatory and cytotoxic effects of particles on human endothelial cells and macrophages in vitro.

Methods

We analysed 22 filters used by critically ill children with electron microscopy and energy dispersion spectroscopy. The average number of particles on the surface as well as their composition was examined. In the in vitro model, human endothelial cells and murine macrophages were exposed to different solutions of glass particles and the cytokine levels assayed to assess their immune response. Levels of IL-1β, IL-6, IL-8, and TNFα were measured.

Results

The average number of particles found on the surface of a filter membrane was 542/cm² and energy dispersion spectroscopy analysis confirmed silicon as one of the major particle constituents. When human endothelial cells and murine macrophages were exposed to different solutions of glass particles (according to the particles found on the filter membranes), levels of IL-1β, IL-6, IL-8, and TNFα were found to be significantly suppressed.

Conclusion

Inline filtration prevents the infusion of potentially harmful particles. The suppression of macrophage and endothelial cell cytokine secretion by particles in vitro suggests that the infusion of microparticles may also contribute to immune compromisation, which is often seen in vivo in the clinical course of PICU patients. These findings and their effect on the clinical outcome of our PICU patients may be further elucidated.