Long-term parenteral nutrition

Nineteen patients (11 women and eight men) aged 20-68 received long-term parenteral nutrition, mostly at home, for six to 63 months (mean 19 months). Indications for LTPN were extensive, active Crohn''s disease in three patients, intestinocutaneous fistulas in three, and short-bowel syndrome in the remaining 13 patients. Subclavian or intra-atrial (Broviac) catheters were most commonly used, for which the average life was four and seven months respectively. Complications of long-term parenteral nutrition included pneumothorax in four out of 48 subclavian vein punctures. Catheter-induced thrombosis of central veins was shown by phlebography 17 times in nine patients, and eight episodes of total occlusion occurred. Two of these patients had pulmonary infarction. Nineteen episodes of catheter sepsis occurred in 11 patients, but only one was fatal. Complications related to intestinal disease included intra-abdominal abscesses and intestinal fistulas, and disturbances of liver function. Five patients died, though in only two was death related to long-term parenteral nutrition. One of these patients died from catheter sepsis, the other had subdural haematoma possibly caused by anticoagulant treatment. Eight of the 14 surviving patients still needed parenteral nutrition. All received a disability pension, but six had an acceptable quality of life with almost normal social activities.Despite problems such as difficulties in maintaining standardised infusion programmes, it was concluded that long-term parenteral nutrition at home is practicable and consistent with an acceptable quality of life.     

Selenium in total parenteral nutrition

In clinical practice, selenium deficiency may arise under conditions of chronic malnutrition and especially after long-term total parenteral nutrition (TPN). In infants receiving long-term TPN, we observed plasma selenium levels as low as those previously reported in Chinese children with Keshan disease. Low plasma selenium levels were also usually associated with very low activities of glutathione peroxidase. Although clinical symptoms of selenium deficiency did not occur in our patients, several cases have been described in the literature, indicating the need for supplementation in TPN. In order to derive at the appropriate dosage, it is proposed to correlate it with the total protein supply. According to our present knowledge, .5–1.0 μg selenium/g of protein appears to be adequate to keep patients in Se balance. For Se repletion of body stores, this dosage has been increased up to 3 μg of Se/g of protein. Advantages and disadvantages of selenite and of selenomethionine as possible supplemental forms of Se for TPN solutions are discussed.     

Lipid emulsions for parenteral nutrition in critical illness

Critical illness is a life-threatening multisystem process that can result in significant morbidity and mortality. In most patients, critical illness is preceded by a physiological deterioration, characterized by a catabolic state and intense metabolic changes, resulting in malnutrition and impaired immune functions. In this context, parenteral lipid emulsions may modulate inflammatory and immune reactions, depending on their fatty acid composition. These effects appear to be based on complex modifications in the composition and structure of cell membranes, through eicosanoid and cytokine synthesis and by modulation of gene expression. The pathophysiological mechanisms underlying these fatty acid-induced immune function alterations in critical ill patients are however complex and partially understood. Indeed, despite a very abundant literature, experimental and clinical data remain contradictory. The optimization of lipid emulsion composition thus represents a major challenge for clinical medicine, to adequately modulate the inflammatory pathways. In the present review, we first address the metabolic response to aggression, the effects of parenteral lipid emulsions on inflammation and immunity, and finally the controversial place of these lipid emulsions during critical illness. The analysis furthermore highlights the pathophysiological mechanisms underlying the differential effects of lipid emulsions and their potential for improving the handling of critically ill patients.     

Selenium depletion in patients on home parenteral nutrition

Severe selenium (Se) depletion was found in nine patients receiving long-term home parenteral nutrition because of short bowel syndrome. Plasma Se ranged from 0–0.51 (median 0.21 μmol/L) and erythrocyte Se ranged from 0.7–2.6 (median 1.8 μmol/gHgb), which was significantly lower than in the controls. Glutathione peroxidase (GSHPx) in plasma and erythrocytes was also decreased. After bolus injections with 200 μg Se/d in the form of sodium selenite for 4 mo, followed by 100 μg/d for 8 mo, plasma Se increased to values slightly but significantly higher than in the controls. Erythrocyte Se reached normal levels in most of the patients after 4 mo substitution, but it remained lower than in the controls. Following Se supplementation, plasma and erythrocyte GSHPx did not differ between patients and controls. These data suggest that all patients receiving long-term parenteral nutrition because of short bowel syndrome should receive at least 100 μg sodium selenite/d when given as bolus injections to avoid Se depletion.     

Prepubertal growth in children with long-term parenteral nutrition

In children who depend on long-term parenteral nutrition (PN), a major goal is to obtain optimal growth. The aim of this retrospective study was to analyze growth in children on long-term cyclic nocturnal home PN, over at least 8 years before puberty. Nine boys and 7 girls were studied. Their mean age at the time of study was 11 years with a mean PN duration of 10.5 (8.6-16.4) years. Diseases were short bowel syndrome (5), intractable diarrhea (4), chronic intestinal pseudo-obstruction (4) and long segment Hirschsprung's disease (3). In each child, periods of at least 2 years were analyzed: either periods of regular growth (R: height gain >50th percentile), or slow growth (S: height gain < or =25th percentile). Results were expressed as mean +/- SD. Comparisons were performed using either Student's test for unpaired data or Wilcoxon's test for paired data. PN provided a mean of 224 +/- 80 mg nitrogen/kg/day and 43 +/- 14 kcal/kg/day equivalent to 50% of recommended supplies. At the time of study, the population presented with weight (W) = -0.7 +/- 0.8 SD and height (H) = -1.5 +/- 1.3 SD. The difference between W and expected W for H (W/H) was significant (p < 0.002). W/H ratio was 105 +/- 11%. For the total PN duration, weight gain was +0.2 +/- 1.5 SD and height loss was -0.75 +/- 1.4 SD. An excess weight gain occurred in parallel with the deflection of height gain. Of the 16 children, regular prepubertal growth was achieved in 4 only. The other 12 showed alternate periods of R and S. In 8 of them, 26.5 years of R and 33.5 years of S were compared, each child being his own control. PN nitrogen and energy supplies were significantly higher during R periods than during S periods. In the absence of any disease or treatment explaining the failure to thrive, inadequate PN supplies, especially in terms of nitrogen supply, are thought to be responsible for a negative nitrogen balance and slowed growth. In case of any deflection away from the individual growth curve, it is recommended to adjust the PN supply early, especially nitrogen supply.