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Biomedical subjects

P W Niemiec

Publications and source records attributed to P W Niemiec.

6 recordsLinked to original sources
PubMed1987

Effect of altered volume of distribution on aminoglycoside levels in patients in surgical intensive care.

The apparent volume of distribution (Vd) of aminoglycosides was found to be increased in 100 patients in a surgical intensive care unit who had gram-negative pneumonia or intraabdominal sepsis and acute physiologic scores greater than 12. Following loading or maintenance doses, carefully timed blood samples were collected for measurements of serum concentrations by fluorescence polarization immunoassay. The Vd, determined by linear regression analysis of a one-compartment model using the Sawchuk-Zaske method, was 0.34 +/- 0.121 L/kg and was larger than the normal Vd of 0.20 to 0.25 L/kg, suggesting a 36% to 70% increase in extracellular fluid volume. Since there is a predictable increase in aminoglycoside Vd in the septic surgical patient, a proportionately larger aminoglycoside dosage is required initially to achieve desirable peak serum levels. Close monitoring of blood levels during maintenance dosing is suggested since dynamic changes in renal function and aminoglycoside Vd occur in the critically ill.

Adult↗
PubMed1985

The effects of total parenteral nutrition on gastrointestinal growth and development.

Total parenteral nutrition (TPN) is vital for the nutritional support of infants with disorders of the gastrointestinal tract that prevent adequate enteral intake. Studies in adult rodents maintained on TPN have demonstrated intestinal atrophy and decreased activity of the brush border enzymes of the small bowel mucosa. We studied the effects of TPN during the phase of rapid intestinal growth and development in piglets. Matched groups of three 6-week-old weaned piglet littermates received a glucose (45 g/kg/d), amino acid (8 g/kg/d), and fat (2.5 g/kg/d) solution intravenously (IV) or by gastrostomy (GF), or were given hog chow (Chow) at an equivalent caloric value for three weeks. No differences were noted in the mean weight gain (13-15 g/kg/d), total serum protein (4.5-4.8 g/dL), BUN (9-12 mg/dL), or Hct (25% to 30%). The IV and GF animals, compared to the Chow animals, had decreased growth of the stomach, small bowel, and pancreas with decreased small bowel mucosal disaccharidase activity. The IV group, compared to Day 0 animal measurements, had decreased small bowel length and weight and pancreatic weight. Histology of the proximal small bowel mucosa in the IV animals showed decreased mucosal depth, villus height, crypt depth, and epithelial cell number from the crypt base to the midvillus. These findings suggest that stomach, small bowel, and pancreatic growth are dependent on the route of administration and/or the composition of the diet, the small bowel mucosa and the pancreas atrophies in young piglets maintained on TPN, the activity of some intestinal brush border disaccharidases are decreased in the small bowel in piglets maintained on either an intravenous or an intragastric infusion of a TPN solution.

Animals↗
PubMed1984

Compatibility considerations in parenteral nutrient solutions.

Information on compatibility of nutrients and drugs with parenteral nutrient (PN) solutions is reviewed and evaluated. Precipitation of calcium phosphate when calcium and phosphate salts are added can be affected by pH, amino acid concentration, amino acid product, temperature, sequence of additives, specific salt used, and time since admixture; precipitate formation can occur gradually over 24 hours. Insulin is chemically stable in PN solutions, but adsorption to the infusion system can cause decreased availability. Poor delivery of vitamin A via PN solutions has been reported. The sodium bisulfite content of amino acid injections may cause degradation of thiamine, but studies simulating clinical use are needed. Folic acid stability in PN solutions has been demonstrated, and phytonadione appears to be stable. Drug administration via PN solutions may be advantageous when fluid intake is restricted or peripheral vein access is limited and in home PN therapy. Summarized are results of studies involving heparin, cimetidine hydrochloride, aminophylline, amphotericin B, iron dextran, hydrochloric acid, corticosteroids, narcotics, metoclopramide, digoxin, and fluorouracil. Many antibiotics are probably stable, especially when administered by co-infusion rather than by direct mixture in the PN solution container. When lipids are mixed in the same container with amino acid-dextrose solutions, compatibility and stability of electrolytes, vitamins, and trace elements must be reassessed. Practical research is needed, and availability of additives should be studied in specific patient populations and for specific PN formulations. Valid conclusions are dependent on careful study design.

Adrenal Cortex Hormones↗
PubMed1983

Stability of aminophylline injection in three parenteral nutrient solutions.

The stability of aminophylline injection in crystalline amino acid-dextrose solutions containing standard additions of electrolytes, vitamins, and minerals was evaluated. Aminophylline injection was added to three parenteral nutrition (PN) solutions in dosages of 0.25-1.50 mg/ml. All of the samples were prepared in duplicate, stored in sealed volumetric flasks, and allowed to stand under normal lighting at room temperature or under refrigeration for 48 hours. Samples were analyzed for theophylline content by reverse phase high-pressure liquid chromatography at 1, 24, and 48 hours. Mean percent theophylline recovery 24 hours after admixture was 101 +/- 10.9%, 101 +/- 4.3%, and 100 +/- 4.3% in the three PN solutions. Solution pH values were stable for 48 hours. Refrigeration and lower amino acid concentrations did not alter stability. Aminophylline is stable in PN solutions for 24 hours in concentrations up to 1.5 mg/ml.

Amino Acids↗
PubMedDate not supplied

Gastrointestinal disorders caused by medication and electrolyte solution osmolality during enteral nutrition.

Enteral feeding tubes represent convenient avenues for medication administration and electrolyte replacement. The frequent association of medication therapy with gastrointestinal disorders during enteral nutrition prompted this evaluation of medication and electrolyte solution osmolality. It is concluded that the hypertonicity of electrolyte replacement solutions and various medications may cause gastrointestinal intolerance in patients. Electrolyte supplementation by parenteral means or by appropriate dilution and mixture with an enteral formula is preferable to bolus administration of undiluted solutions via the feeding tube. Routine admixture of medications such as antibiotic suspensions to enteral formulas cannot be recommended at this time pending specific study of drug compatibility and availability from enteral tube feeding systems.

Anti-Bacterial Agents↗