Extraction of diethylhexylphthalate from total nutrient solution-containing polyvinyl chloride bags.

Total nutrient solution (TNS) is a new method for delivering total parenteral nutrition (TPN) by admixing dextrose, amino acids, and lipids in a single container. Recommendations are to use nonpolyvinyl chloride (PVC) containers for admixture of these solutions. PVC is a hard, brittle, and inflexible substance, and plasticizers, predominantly diethylhexylphthalate (DEHP), are added to impart flexibility. DEHP is a lipid soluble suspected carcinogen, hepatotoxin, and teratogen which has been shown to leach from PVC products containing lipophilic admixtures. The purpose of this study was to quantitate the amount of DEHP which leaches from PVC bags containing TNS. Six study groups, which contained three formulas stored at 25 degrees C +/- 2 degrees C and 4 degrees C +/- 1 degree C, were assayed for DEHP at time 0, 12, 24, 48 and 72 hr, 1 wk, and 3 wk using high-performance liquid chromatography. The control group contained an amino acid source, a carbohydrate source, and standard electrolytes, and the other groups contained a 10% lipid source or a 20% lipid source in addition to the constituents of the control group. Lipid-containing groups demonstrated detectable levels of DEHP at 48 hr, and DEHP content increased in these groups throughout the 21-day study. DEHP concentrations were lower in lipid-containing groups stored at 4 degrees C than comparable groups stored at 25 degrees C.

Sterility testing of home and inpatient parenteral nutrition solutions.

The microbial contamination rate was compared for parenteral nutrition solutions prepared by patients for home use and by pharmacy personnel for inpatient use. Phase I validated the Ivex 0.22-micron inline filter as a tool for microbiological testing by inoculating small numbers of organisms in 5% dextrose injection and testing for recovery. Phase II validated the same method for determining microbial contamination of total parenteral nutrition (TPN) solutions. Phase III compared inpatient and home TPN microbial contamination rates using the methodology validated in phase II. Test organism inocula used in phase I and II were Candida albicans, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. All contaminated solutions in phase I showed visual turbidity within 48 hr, and all test organisms were recovered and identified. All phase II-contaminated TPN solutions showed visual turbidity after 96 hr, and all test organisms were recovered and identified. One hundred postinfusion TPN samples were collected randomly during phase III from inpatient parenteral nutrition patients. Six patients and two hospitals participated in the study. None of the 44 home parenteral nutrition samples and none of the 56 inpatient TPN samples developed visible turbidity. Subcultures of each sample on blood agar were negative for microbial growth. This described methodology offers an effective means to establish contamination rates of parenteral nutrition solutions after administration.

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.