IMPACT OF PARTICULATE CONTAMINATION IN CRYSTALLOID CARDIOPLEGIC SOLUTIONS - STUDIES BY SCANNING AND TRANSMISSION ELECTRON-MICROSCOPY

The amount of particulate matter present in Bretschneider's cardiopleg ic solution (HTK) was assessed by laser-mediated particle counting. Pe rmissible levels of contaminant particles with a distribution of diame ters between 0.2 and 20 mu m were found. a significant further increas e in the particle count was observed when the fluid was administered f or clinical use, which resulted in the additional release of particles from, for example, the infusion kit, which included an in-line filter with pores of 270 mu m. Filtration of the HTK solution by a terminal inline filter (0.2 mu m) significantly reduced the number of particles . In order to determine the chemical composition and the potential haz ards of the particulate material we used scanning electron microscopy in combination with energy dispersive X-ray analysis and transmission electron microscopy to examine specimens taken from heart tissue obtai ned from Gottinger minipigs after cardioplegia and from humans undergo ing mitral valve replacement after cardioplegia and reperfusion. Parti cles of various diameters were found either to be plugging coronary ca pillaries, to be adherent to the endothelial layer, or to be engulfed by polymorphonuclear (PMN) granulocytes, which appeared to be activate d. Some of the PMN granulocytes were apparent in the endothelial layer . It is recommended, therefore, that a terminal in-line filter (0.2 mu m) should be routinely used.