Precipitate analysis from an indwelling total parenteral nutrition catheter.

The composition of a precipitate obtained from a silastic right atrial catheter was determined. The precipitate was collected and washed with deionized water thoroughly before subjecting portions of it to organic and inorganic analysis. Inorganic analysis was conducted using scanning electron microscopy and x-ray spectroscopy for sodium, aluminum, silicone, sulfur, chlorine, and calcium. Phosphorus analysis was conducted by a commercial laboratory. Organic analysis was conducted by thin layer chromatography with cholesterol, phosphatidyl serine, phosphatidyl choline, phosphatidyl ethanolamine, and sphingomyelin as standards. Silicone, calcium, and phosphorus and three organic compounds, which could not be conclusively identified, were found. The precipitate was most likely calcium phosphate intermixed with silicone oil lubricant and residual total parenteral nutrition (TPN) solution. This formed in the catheter at body temperature probably due to incomplete catheter flushing.