Ascending contamination of a jejunostomy feeding reservoir

In general bacterial contamination of enteral feeding solutions is considered to be exogenous in origin. However, during feeding through catheter jejunostomy another source of contamination seems possible. We describe a patient in whom bacterial contamination of the feeding solution given through a catheter jejunostomy occurred frequently. Microbiological evaluation of several feeding samples showed that with this particular type of catheter enterostomy contamination was dual in origin. A not aseptic manipulation of the feed prior to administration led only to slight contamination. Most of the contamination however was endogenous--ie. ascending from the gut of the patient. In contrast to some previous studies, no clinical or laboratory deterioration could be observed in relation to the contamination. The food value of the feed expressed as the glucose concentration was significantly reduced after contamination with the causative organisms.     

Creaming and plasma clearance rate of intravenous fat emulsion in critically ill patients

Intravenous fat emulsion incubated with serum or plasma in vitro may result in the aggregation of fat (creaming). Twenty critically ill patients were tested for in vitro creaming of the fat emulsion Intralipid. An intravenous fat tolerance test was used to determine the plasma clearance rate of Intralipid in each patient. Eleven patients (55%) were found to be creamers. These patients had a higher mean plasma clearance rate of Intralipid than non-creamers (5.73 +/- 0.56 vs. 2.77 +/- 0.37% per min; p < 0.001); however, the rates of both groups were within the range reported in normal healthy subjects. Mean C-reactive protein concentration was significantly higher (p < 0.01), and albumin levels were lower (p < 0.01) in creamers compared to non-creamers. Ionized calcium levels did not differ between the two groups. The results of this study indicate that in vitro creaming is common in acutely ill patients. The clinical significance of creaming is probably minimal since creamers tolerated 50 to 100 g/day of intravenous fat emulsion while receiving total parenteral nutrition. Creaming was uncommon when the fat was mixed with blood in vitro.     

Bacterial contamination of intravenous line side ports of different designs

A prospective clinical study was undertaken to elucidate the question whether contamination of side ports of intravenous cannulae can be avoided by covering them with a disinfectable latex membrane. Two stopcocks equipped with membrane filters were mounted in the infusion line, one of them with a side port of the same configuration as that on a Venflon^® cannula and the other with a side port covered with a disinfectable latex membrane. The series comprised 42 patients who received parenteral nutrition for a total of 79 days. Both side ports were used for flushing the infusion line six times daily. Bacterial cultures were performed from filters and from 30 bottles of flushing fluid. Twenty-four percent of the filters on side ports of the Venflon type showed bacterial growth, compared with 10% of those on side ports covered with a disinfectable latex membrane. Bacterial growth was observed in the flushing fluid from one of the 30 bottles tested. The study demonstrated that side ports are a common route of bacterial contamination of infusion systems. The risk of contamination can be significantly reduced by equipping side ports with a distinfectable latex membrane.     

Embolisation of silicone rubber catheters used for intravenous feeding; a preventable complication

The advantages of silicone rubber central venous catheters are widely recognised, but embolisation of the whole catheter can occur due to malfunction of the hub which is used to clamp the catheter to the female luer connector. Two cases are described in which silicone rubber catheters were successfully removed from the heart using percutaneous techniques. A modification is suggestion to prevent this complication.     

Study of copper,zinc, magnesium and cadmium in ICC patients,parents and siblings

Twenty-seven histopathologically proved cases of Indian childhood cirrhosis (ICC), 13 parents (father and mother) and nine siblings of ICC patients were studied from serum and urinary Cu, Zn, Mg and Cd levels by Atomic Absorption Spectrophotometer (AAS). Milk and drinking water from various sources were analysed for Cu, Zn, Mg and Cd contents, as was milk boiled and stored for up to six hours in various utensils. Serum and urinary Cu excretion were high (P < 0·001) in ICC patients and within normal limits in siblings and parents. In ICC patients most hepatocytes contained multiple, coarse and dark brown orcein staining granules representing Cu associated protein. Serum Zn was low and urinary Zn excretion high in ICC patients (P < 0·001 and P < 0·01 respectively) and within normal limits in siblings and parents. Mg and Cd in serum and urine of ICC patients, siblings and parents were within normal limits. Cu content of milk boiled and stored in peetal (brass) utensils was high and directly related to the duration of storage; there was no change in Cu level in milk boiled and stored in steel and aluminium utensils. Zn, Mg and Cd levels in milk boiled and stored in peetal (brass) utensils remained unchanged. The levels of these elements in drinking water from various sources were also within limits as recommended by WHO 1971. Milk boiled and stored in peetal (brass) utensils seemed to account for increased Cu intake. Excessive Cu intake in ICC should be eliminated by avoiding brass utensils for boiling and storing milk. Some treatment to chelate excess Cu is also warranted.     

A controlled trial of fixed versus tailored calorie intake in patients receiving intravenous feeding after abdominal surgery

Excessive intravenous calorie intakes have been shown to increase fat deposition and CO2 production with deleterious results. A controlled trial has therefore been performed to determine whether there is clinical benefit from tailoring calorie intake of intravenously fed patients to the patient's metabolic expenditure. Twenty patients requiring intravenous feeding after abdominal surgery were randomly allocated to receive either (i) a constant regimen containing 2 600 calories and 15.55 g nitrogen or (ii) a varied regimen with a fixed calorie: N2 ratio of 167:1 but with the calorie intake adjusted according to the previous day's metabolic expenditure. Only one patient had a requirement of greater than 2 600 calories; there was no difference in mean RQ during intravenous feeding between the constant regimen (0.90 +/- 0.10 s.d.) and the varied regimen (0.90 +/- 0.09 s.d.) and no significant difference in peak CO2 production. Excess calorie intake over expenditure did not correlate with increased positive nitrogen balance but on the varied regimen patients receiving a higher nitrogen intake tended to be in more positive nitrogen balance. This study suggests that a fixed calorie intake of 2 600 calories per day is suitable for adult patients requiring intravenous feeding after abdominal surgery but currently prescribed nitrogen intakes may be suboptimal.     

Do fibre containing enteral diets have advantages over existing low residue diets?

This study investigated the influence of fibre on the pattern of absorption of protein and carbohydrate following administration of polymeric enteral diet and also the effect of added fibre on frequency of bowel action, stool weight and gastrointestinal side effects during enteral nutrition. No difference was seen in frequency of bowel action, stool weight or gastrointestinal side effects in five patients fed with either a fibre free polymeric diet or with the same diet augmented with 24 g fibre/24 h. Addition of fibre did not significantly alter breath hydrogen excretion. In an oral tolerance test on six normal subjects, the post prandial rises in blood glucose and levels of 17 amino acids were similar on ingestion of a fibre containing or fibre free test meal.     

Clinical implications of continuous measurement of energy expenditure in mechanically ventilated patients

Energy expenditure was monitored in 20 critically-ill mechanically ventilated patients using the Siemens-Elema Oxygen Consumption Calculator (OCC 980). Energy expenditure was measured continuously over the 24-h period in all patients (altogether, over 2500 patient hours; range 48-288 h). A predicted energy expenditure was calculated for each patient from standard tables for basal metabolic rates modified according to previously published reports on the influence of trauma, infection and elevated body temperature. For all patients combined, the agreement between the predicted and the measured energy expenditure was good. However, in individual patients the measured energy expenditure varied between 48 and 148% of the predicted value. The measured energy expenditure in surviving traumatized and/or septic patients correlated well (95-100%) with the predicted value at the time when weaning off the ventilator could be initiated. On the first day of measurements, the energy expenditure (in % of the predicted value) in the six patients who later died was significantly lower than in surviving patients (84 +/- 6 vs 107 +/- 2%; p < 0.01). Over a 24-h period, energy expenditure, defined as the value noted during a stable 30-40-min period of measurement, varied between 12 and 50% in the individual patients. This study shows that energy expenditure cannot be accurately predicted in the individual patient, that an energy expenditure below predicted values appears to be indicative of a poor prognosis and that short periods of energy expenditure monitoring may fail to reflect 24-h conditions.     

Clonal diversity in a single isolate of the malaria parasite Plasmodium falciparum

Clones of an isolate of Plasmodium falciparum from Mae Sod (Thailand) were prepared by a dilution procedure. Some of the parasite cultures thus obtained have been typed for the following characters: (i) electrophoretic variants of three enzymes; (ii) susceptibility to chloroquine and pyrimethamine; (iii) antigen diversities recognized by ten strain-specific monoclonal antibodies; (iv) presence or absence of knobs on infected erythrocytes and (v) two-dimensional PAGE variants of seven proteins. Amongst the clones there was variation involving each of these five characters. At least seven different types of clones were found in ten cultures produced by dilution. The amount of phenotypic variation within a single isolate has thus been shown to be surprisingly great. Variations in drug susceptibility and antigens are considered to be particularly important in view of their relevance to anti-malarial treatments.     

Bacterial contamination of ‘Venflon’ intravenous cannulae with valved injection sideport

Eighty-eight intravenous cannulae with valved injection sideports were examined bacteriologically after approximately three days (64–80 h) normal clinical use. Three methods of culture of the cannulae were used, which distinguished contamination of the outer and inner surfaces as well as detecting bacteria remaining on the inner cannula surface following a washing procedure of the lumen. Of the cannulae sampled, 40·9 per cent were found to be contaminated on their inner surfaces and no correlation was obtained between use of the sideport and contamination of the cannulae at this site. It was concluded that contamination of a cannula lumen did not necessarily result in bacteraemia.     

Changes in muscle and plasma amino acid metabolism in severe malnutrition--the influence of total parenteral nutrition

The concentrations of free amino acids in muscle and plasma were determined in nine female patients with severe anorexia nervosa before and after 3 to 5 weeks of total parenteral nutrition (TPN). The patients had lost 25 to 42% of their pre-morbid weight. During TPN their weight gain was around 2.5 kg/week. Initially total non-essential amino acids (NEAA) in muscle were decreased 30% compared to controls. The major part of this depletion was due to a 40% reduction in glutamine. After TPN the level of glutamine normalized. Alanine, being normal before TPN, decreased after TPN. Proline and several other non-essential amino acids in muscle were decreased before and after TPN. Total essential amino acids (EAA) in muscle were initially normal and were not significantly affected by TPN. Total NEAA in plasma were decreased at admission and normalized after TPN. Total EAA in plasma, however, were normal both before and after TPN. This study demonstrates that severely malnourished patients with anorexia nervosa have changes in amino acid patterns in both muscle and plasma. These changes were largely, though not completely, reversed after 3 to 5 weeks of TPN.     

Nutritional intake after colorectal surgery: a comparison of a traditional and a new post-operative regimen

The energy and protein intake was studied for 12 days after colorectal surgery in 36 patients. Eighteen patients followed a traditional management with nasogastric suction until bowel movements occurred after which a liquid diet, protective diet and normal food were successively administered. In a subsequent period a new regimen was introduced. Nasogastric suction was not used. Instead, 18 patients received liquid diet from the first post-operative day and normal food, when the patient wanted to eat it. In addition, the nutritional intake was supplemented by protein-enriched refreshing drinks and milk products between the meals. The new regimen was tolerated without discomfort and resulted in a significant increase in protein intake (43 g/day vs. 26 g/day, p<0.001) and energy intake (78% vs. 71% of the basal metabolic rate, p<0.05). The increase was most pronounced in the first 4 days after the operation. Finally, the weight loss was significantly lower on the new regimen (1.8 kg vs. 3.9 kg, p<0.001).     

Aminoacid imbalance and malnutrition in liver cirrhosis

The reason branched chain aminoacids are decreased and aromatic aminoacids increased in chronic liver failure is unclear. Branched chain aminoacids are mainly catabolised in muscles, and it is known that protein energy malnutrition may decrease the concentration of these aminoacids in plasma. In this study we have evaluated the nutritional status of a group of cirrhotics and compared it with their plasma aminoacid imbalance. Fourteen patients were considered as well-nourished and nine as malnourished. Plasma levels of branched chain aminoacids were significantly decreased and the phenylalanine increased in the malnourished group. Arm muscle circumference was significantly correlated with branched chain aminoacids. In conclusion our data suggest that malnutrition may contribute to the low levels of these aminoacids in patients with liver cirrhosis.     

Post-operative substrate utilisation and gas exchange using two different TPN-systems: glucose versus fat

Twenty patients were studied over the first 4 post-operative days following abdominal aortic surgery. Ten patients had 93% of their non-protein energy as glucose and insulin was given to keep blood glucose below 10 mmol/l. The other 10 patients had 80% of non-protein energy as fat (Intralipid). Amino acids corresponding to 12 g of nitrogen were given in both groups. Gas exchange, nitrogen balance, phosphate balance, vanillylmandelic acid (VMA) excretion, 1- and 3-methylhistidine in urine, acute phase proteins, immunoglobulins and albumin were followed. Substrate utilisation was calculated from indirect calorimetry data and nitrogen excretion. Metabolism in the early post-operative phase was found to adapt to the nutrition regimen given even though the composition was extreme either in fat or carbohydrate content. The glucose-insulin regimen had a better nitrogen sparing effect and based on the difference in 3-methylhistidine excretion it is suggested that mainly protein muscle benefitted from this. Regardless of the TPN-regimen given, those patients whose RQ deviated the most from the average in their group had the highest nitrogen excretion. The two groups showed no differences in plasma proteins and catecholamine excretion.     

Glucose balance and muscle glycogen during TPN in the early post-operative phase

In order to study how muscle glycogen is influenced by different nutritional regimens in the early post-operative period we took muscle biopsies from 20 patients preoperatively and on the fourth post-operative day after abdominal aortic surgery. Ten patients received 93% of non-protein energy as glucose, 7% as fat (Intralipid) and insulin was given to keep the blood glucose below 10 mmol/l. The remaining patients had 80% of non-protein energy as fat (Intralipid). Amino acids constituting 12 g of nitrogen daily were given to both groups. Daily measurements of gas exchange (oxygen uptake, CO2-production) were performed and from these data glucose balance was calculated as the difference between glucose intake and glucose expenditure. Muscle biopsies were analysed for glycogen, adenosine triphosphate, glucose-6-phosphate, lactate and citrate. We found that it was possible to maintain muscle glycogen stores at pre-operative levels with a glucose-insulin regimen. With the fat regimen there was a 31% decrease in muscle glycogen and two patients had a negative glucose balance despite the fact that 150 g of glucose were given. Average glucose balance throughout the study correlated positively with glucose intake. A significant correlation between glucose on the third day and change in muscle glycogen content was found. Muscle content of adenosine triphosphate, glucose-6-phosphate, lactate and citrate were similar in both groups.     

Measured and predicted resting energy expenditure in clinically stable patients

Resting energy expenditure (REE), measured by bedside indirect calorimetry, was compared to estimated REE by the Harris-Benedict and Kleiber predictors in 200 clinically stable hospitalized patients (100 males, 100 females) and 72 healthy control subjects (20 males, 52 females).Mean predicted values were not significantly different from measured REE for the male patients and control subjects, but measured REE was significantly overestimated by the Kleiber formula in female patients and controls (p<0.01). In comparison to control subjects, a substantially larger range of individual differences between measured REE and resting energy expenditure as estimated by the Harris-Benedict and Kleiber formulae existed among the male and female patient samples. Measured REE was over or underestimated by greater than 10% via the Harris-Benedict predictors in 40% of the patients but only 20% of the healthy controls. The Kleiber formulae were inappropriate for 46% of the individual patients and 33% of the normal subjects.Since no method exists for identifying the clinically stable patient for whom REE cannot be estimated via these commonly employed predictors, the bedside measurement of resting energy expenditure is the most appropriate method for deriving caloric expenditure and designing subsequent caloric provision regimens for adequate and safe nutritional repletion or maintenance.     

Metabolic response to experimental trauma: the time relation of post-traumatic protein metabolism

The relationship between time and the post-traumatic metabolic response was studied in a commonly used experimental model of trauma. Twenty nine rats underwent laparotomy and jugular vein sham catheterization as the standard trauma. The rats were fed ad libitum and compared to pair fed controls in terms of nitrogen balance and liver protein synthesis. The pairs of rats were divided into three groups according to the duration of the experiment, which was 24 h, 48 h or 72 h. The nitrogen balance was calculated daily and the liver protein synthesis in vitro measured in 10 rats after 48 h with an asanguinous perfusion system using L-(1-C(14))-Leucine. The metabolic effect of trauma was first detected in liver protein synthesis, which was diminished in the early post-traumatic period (percentage synthesis rates: post-traumatic 34.6 +/- 10.7 and pair fed 60.4 +/- 21.3, Mean +/- SD, P < 0.05). During this period the whole body nitrogen balances were similar (post-traumatic -1.200 +/- 1.440 and pair fed -0.880 +/- 1.130, gN/kg/48 h, mean +/- SD). On the third day, the response to nitrogen intake and the nitrogen balance became significantly worse in the post-traumatic rats (post-traumatic 0.214 +/- 1.680 and pair fed 1.236 +/- 1.220, gN/kg/day, mean +/- SD). These observations suggest that, firstly, the 'flow' phase has its onset on the third post-trauma day, and secondly that trauma does decrease liver protein synthesis, and this decrease lasts at least through the 'ebb' phase. The results indicate the necessity of defining the metabolic phase in experimental studies of post-traumatic metabolism.     

Long-term follow-up of children breast-fed by mothers receiving depot-medroxyprogesterone acetate

A long-term follow-up study compared development and health of 128 breast-fed children whose mothers had received depotmedroxyprogesterone acetate (depot-MPA) while lactating and 142 control children whose mothers had used mechanical contraceptives or no contraceptives or had undergone sterilization. The children, who were approximately 4-1/2 years old at follow-up, showed no ill effects on their growth and development and health status from exposure to depot-MPA. Depot-MPA-treated mothers lactated significantly longer than controls and also had greater parity than controls. These factors apparently contributed to a difference in weight at follow-up. Compared with the SempePedron standard, more of the depot-MPA group were underweight and more controls were overweight.     

Effect of leucine or ketoleucine on nitrogen metabolism in postoperative patients receiving energy substrate

It has been shown that ketoisocaproate (KIC) spares nitrogen (N) in fasting postoperative patients while leucine does not. The aim of the present study was to determine if KIC when compared with leucine, decreases nitrogen excretion in postoperative patients receiving energy substrate. Thirty patients undergoing gynecological surgery (hysterectomy with or without lymphadenectomy) were randomized to receive for the first 3 postoperative days one of the following I.V. solutions per kilo and per day: 3 g glucose (group A) 3 g glucose + 90 mg Leucine (group B), 3 g glucose + 100 mg ketoleucine (group C). The output of 3 methylhistidine (3 MEH), total nitrogen and creatinine were measured daily. Although muscle protein breakdown measured as 3 MEH/creatinine molar ratio was significantly reduced in group C as compared with A and B, total nitrogen and creatinine did not differ significantly in A, B and C. Thus, the metabolic effects of KIC in postoperative patients are appreciably influenced by glucose infusions and the usefulness of KIC infusions in such patients needs further study.