Treatment effects of parenteral vitamins in total parenteral nutrition patients.

To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.

Total body water and total body potassium in anorexia nervosa.

In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

Estimation of fecal nitrogen in patients with liver disease.

The use of a fecal nitrogen (FN) predictive equation (Am J Clin Nutr 1978; 31:12-22, Cheng) based on dietary nitrogen intake (Nin) [FN (mg/kg/day) = 10.817 + 0.03 Nin(mg/kg/day)] was evaluated in patients with liver disease with and without concomitant lactulose therapy. Ten male cirrhotics were studied in 27 3-day nitrogen balance studies including measured daily total urinary nitrogen, total FN, and Nin calculated from weighted food records. The Cheng formula accurately predicted FN in cirrhotics not receiving lactulose who demonstrated normal digestion and absorption of dietary protein. However, the formula did not accurately reflect FN excretion in patients receiving lactulose who showed impaired protein digestibility and significantly increased fecal weight. The Cheng predictive equation is a useful index of FN excretion in patients with liver disease whose digestive and absorptive capacities are not compromised by exogenous factors.