Towards cheaper intravenous nutrition

Parenteral nutrition: an overview of current practice

Nutritional support should always be provided via the gastrointestinal tract if possible, but parenteral nutrition, i.e. infusion of nutrients directly into the venous circulation, can be a safe and effective method of nutritional support when used in carefully selected patients and monitored appropriately. A multidisciplinary team approach to patient selection, assessment and monitoring is recommended. Access for parenteral feeding is traditionally via a central vein, but the peripheral route can be used for short-term feeding and should be considered for the majority of patients. Nutritional requirements should be assessed on an individual basis and a feeding regimen designed using standard formulations where possible. The transition back onto oral or enteral nutrition should be closely supervised by a dietitian. Parenteral feeding can be provided to the community if appropriate, but thorough training, monitoring and support are essential.

[Perioperative artificial nutrition in elective surgery. A descriptive study of practice patterns in France]

OBJECTIVE

To analyse the practice patterns of perioperative artificial nutrition in France before the Consensus Conference held on 16 december 1994 and to compare them with the recommendations produced by this Conference.

STUDY DESIGN

Retrospective cross-sectional practice patterns study.

PATIENTS

Sample of patients collected from general or digestive tract surgeons, including for each one the last two patients having had before 10 December 1994 either elective upper (oesophagectomy, duodenopancreatectomy) or elective lower (colectomy) abdominal surgery. The response rate to the 2, 150 circulated questionnaires was 14% (309), producing a sample of 601 patients (49% with upper abdominal surgery, 51% with lower abdominal surgery).

RESULTS

The geographical distribution of surgeons who replied and their type of activity (private or public) was similar to the national pattern, however with some underrepresentation of the larger Paris area. The duration of pre- or postoperative artificial nutrition was bellow seven days in 36% of the cases, and above this delay in 64% of the cases. Artificial feeding rates for upper abdominal surgery, were 9 and 75%, respectively (duration of artificial feeding of 7 days and more being only considered). For lower abdominal surgery, these rates were 5 and 41%, respectively. Enteral nutrition was given in 13% of preoperative cases and 19% of postoperative ones; the others received parenteral nutrition. When compared to the recommendations by the Consensus Conference, these results show an insufficient use of preoperative artificial nutrition in patients with malnutrition (only 22% of them received it) and an excessive use in postoperative patients, particularly after lower abdominal surgery. Furthermore, the caloric intake was in accordance with the recommendations in only 20% of the cases. It was too high in 38% of the cases and insufficient in 47% of them. Similarly, the postoperative nitrogen intake complied with the recommended figures in only 5% of the cases.

CONCLUSION

This study highlights large discrepancies between the recommendations by the Consensus Conference and current practice patterns. It questions the efficiency of this therapy as it is implemented today and generates high and unwarranted expenses.

Survival to lipopolysaccharide, cytokine release and phagocyte functions in mice treated with different total parenteral nutrition regimens

Effects on host defenses of Total Parenteral Nutrition (TPN) with long- (LCT) and medium-chain triglycerides (MCT) were studied. Survival to lipopolysaccharide (LPS) challenge, blood clearance of Escherichia coli, in vivo and in vitro production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were investigated. In BALB/c mice, LCTs produced a 25% reduction in mortality, compared with controls. TPN performed with a LCT plus MCT mixture reduced mortality by 50%. Spasms appeared after 18 h and 12 h respectively in mice treated with LCT-MCT mixture or LCTs alone, respect to controls (8 h). The LCT-MCT mixture produced a 67% blood clearance of E. coli after 1 h, while the treatment with LCTs alone had no significant effects compared to controls (about 40%). The LCT-MCT mixture induced a 50% increase in chemiluminescence respect to controls. A 33% increase was observed in rats treated with LCTs alone. TNF-alpha serum levels after challenge with LPS were not modified by any of the triglycerides or their combinations. IL-6 increased by 43% with LCT-MCT mixture and by 39% with LCTs alone versus controls. After a 3 h in vitro treatment with LCTs, human monocytes were stimulated to release TNF-alpha at levels higher than those stimulated with the LCT-MCT mixture, and respect to controls. In contrast after 3 h the stimulation with LCT-MCT mixture induced a higher IL-6 release than controls and cells stimulated with LCTs alone, or with LPS.

Medium- and long-chain triglycerides have different effects on the synthesis of tumor necrosis factor by human mononuclear cells in patients under total parenteral nutrition

OBJECTIVE

Lipid emulsions containing both long- and medium-chain triglycerides (LCT/MCT) have been used in total parenteral nutrition (TPN) regimens and seem to have certain advantages for seriously ill patients. The aim of the present study was to investigate the effect of lipid emulsions containing 100% LCT or 50% LCT/50% MCT on tumor necrosis factor (TNF) production by human mononuclear cells.

STUDY DESIGN

This was a prospective study, in which 20 malnourished patients were randomly allocated to receive either 100% LCT or 50% LCT/50% MCT for > 30 days. We measured TNF synthesis before initiation of TPN, as well as at 15 and 30 days during TPN.

SETTING

Departments of Medicine and Surgery, Patras University Medical School, Patras, Greece.

PARTICIPANTS

Members of the staff of the Departments of Medicine and Surgery, Patras University Medical School.

RESULTS

We found that TNF production was significantly (p < 0.01) elevated at 30 days in the LCT group, while no significant differences were detected in the LCT/MCT group.

CONCLUSIONS

It is concluded that long-term TPN formulas, where LCT have been partially replaced by MCT, do not change TNF synthesis by peripheral blood mononuclear cells, and this may be beneficial in seriously ill, cachectic patients.

Total parenteral nutrition by peripheral vein — Substitute or supplement to the central venous route? A prospective trial

51 consecutive gastroenterological patients who required total parenteral nutrition (TPN) were entered into this study. Two patients were withdrawn because of specific nutritional requirements, leaving 49 patients for randomisation. 23 patients were allocated to receive peripheral parenteral nutrition (PPN) and 26 to receive feeding through a central venous line (CPN). There was no significant difference between the groups with respect to the median duration of feeding (9.4 +/- 3.6 days; 12.0 +/- 7.8 days) but significant morbidity occurred more frequently in the CPN group (11%) compared to the PPN group (0%). TPN by the designated route was not possible in 4 patients in the PPN group and in 3 of the CPN group. Of the 19 patients commenced on PPN, 13 continued without complication until resumption of oral feeding (median 10.7 +/- 3.2 days); 6 of these patients had to be converted to central venous feeding for completion of their nutritional requirements. Of the 23 patients commenced on CPN, 21 completed their nutritional course (median 11.8 +/- 5.3 days), 2 patients in the CPN group required conversion to PPN to complete their nutritional course. This study shows that PPN is a feasible, safe alternative to CPN in many patients. It is not necessary to subject all patients who require TPN to the risks and expense of central venous cannulation.

Importance of district of residence and known primary site for bowel cancer survival: analysis of data from Wessex Cancer Registry

STUDY OBJECTIVE

The aim was to compare survival with colon and rectal cancer across the 10 districts of Wessex taking into account the age and sex of the individual.

DESIGN

The study was based on registrations on the Wessex Cancer Registry between 1979 and 1984 with colon and rectal cancer. Survival up to 31 December 1986 was examined using a Cox regression model; individuals surviving to the end of the follow up period were treated as censored in the analysis. Survival was examined in the first fortnight, the first month, and the first six months after registration separately.

PARTICIPANTS

The data comprised 6239 residents of the Wessex Region who had been diagnosed with colon cancer and 3203 residents diagnosed with rectal cancer. For 140 cases survival data or age were missing and these cases were excluded.

MEASUREMENTS AND MAIN RESULTS

Results are presented in the format of a league table giving the order of districts from lowest to highest survival rates. No significant differences in survival are found between districts in relation to rectal cancer. We find that one or two districts have consistently high or low survival rates with colon cancer in various periods of follow up, but cannot differentiate between the districts in the centre of the list. Site unspecified is considered as an explanatory variable; it is more predictive than district, and it approaches the importance of age in explaining survival with colon cancer.

CONCLUSIONS

There are significant differences in survival with colon cancer between districts; however data on stage at registration are not available and we are unable to say whether the differences in survival are due to differences in stage at diagnosis or differences in survival with similar stage at diagnosis. We found that cases where the site of the cancer within the colon was not recorded on the register have significantly lower survival, and we suggest that site unspecified may be related to stage at diagnosis.

Effects of different lipid emulsions on lymphocyte function during total parenteral nutrition

A prospective randomized study of the immunological effects of three total parenteral nutrition (TPN) regimens in patients undergoing preoperative parenteral nutrition was conducted. In one regimen the calories were derived solely from glucose. The others were identical except that 50 per cent of the calories were provided as lipid emulsion, in one as long-chain triglycerides (LCT) only while the other contained half the fat as medium-chain triglycerides (MCT) and half as LCT (MCT/LCT). Natural killer (NK) activity and lymphokine-activated killer (LAK) activity were significantly higher after TPN with the MCT/LCT solution. A significant fall in LAK activity occurred after TPN with the LCT solution. The interleukin 2 content in supernatants from activated T lymphocytes was significantly higher after TPN with the LCT-containing solution. Solutions containing LCT and those containing MCT perturb cytokine interactions, but this is less with MCT-containing solutions, which may augment certain responses. These observations may have implications for the design of TPN regimens.

Immunorestorative effect of lipid emulsions during total parenteral nutrition

This prospective in vivo cross-over study investigated the effect of Intralipid on immune responses. Twenty-three patients were randomly allocated to receive one of two alternative total parenteral nutrition (TPN) regimens for the first 7 days and the other regimen for the second 7 days. Only one of the regimens included a fat emulsion to provide 50 per cent of the calorific requirement. Immunological studies were performed on days 0, 7 and 14. These included peripheral blood T cell subsets, antibody dependent cellular cytotoxicity and basal and maximal Interleukin 2 production. All immunological parameters were significantly augmented during total parenteral nutrition using the lipid based regimen. No such change was seen during intravenous feeding with carbohydrate based TPN. It is concluded that, far from being immunosuppressive, the incorporation of a fat emulsion into a TPN regimen has immunostimulatory properties.