El-Gallal A.R.S., Yousef S.M.

Aljala Hospital, Plastic Surgery and Burns Unit, Benghazi, Libya

SUMMARY. This paper presents our experience with enteral nutritional support when it is supplemented parenterally, and demonstrates its value in preserving the nitrogen balance and maintaining nutritional integrity in severely burned patients. Thirty Libyan burned patients (18 males, 12 females) were selected prospectively for this study among patients admitted with an extensive burned surface area (20-50%) over a 5-yr period (1995-2000) to our burn unit, which is based at Aljala Hospital in Benghazi, Libya. The selection was made to form two comparable groups. The patients were randomly assigned to a type of nutritional support: either enteral support supplemented parenterally (group A) or enteral support alone (group B). Apart from nutrition, burn management was the same for all patients in both groups. We used changes in the patients’ body weight and total serum protein to assess the effectiveness of the nutritional support given. The results were compared and the outcome showed significant differences between the groups as regards their nutritional response.

Introduction

The well-known phenomenon of post-traumatic hypercatabolism, which causes considerable tissue breakdown and exhaustion of body stores, is seen at its maximum in extensively burned patients; its magnitude is directly related to the extent and severity of the burn injury.

The contributing factors include high production of catecholamines and other stress (anti-insulin) hormones. This accelerated metabolism is augmented by pain, anxiety, hypovolaemia, and infection, in addition to the heat loss (hypothermia) directly caused by vasodilatation (hyperaemia) and evaporation of surface water. Unless early supportive measures are taken to preserve the nutritional integrity of burn patients, this intense catabolic response will lead to considerable pathophysiological and metabolic changes that disturb nearly all systems of the body and the functions of the vital organs, lowering body resistance and suppressing its healing capacity.

The present study was conducted in the Burn Shock Room at Aljala Hospital, Benghazi (Libya) with the aim of evaluating the nutritional response of severely burned patients to parenterally supplemented enteral nutrition. The results are compared with results obtained in another comparable group that received the same enteral support but without parenteral supplementation.

Patients and method

Aljala Hospital in Benghazi is a 450-bed teaching hospital providing general surgical emergency care, including burn management, for the eastern part of Libya.

Thirty Libyan patients (18 males and 12 females) with deep and deep-dermal burns (20-50% burned body surface area [BSA]) were prospectively selected over a 5-yr period (1995-2000). The patients were randomly allocated to either group A (enteral nutrition supplemented parenterally) or group B (enteral nutrition) in order to form two comparable groups as regards percentage of BSA and the patients’ age, sex, and body weight. Apart from their nutritional support, both groups received the same burn management.

The enteral nutritional support used during this study included (Fig. 1):

• ready-made feeding diet (Nutricomp® F), consisting of 186 g carbohydrate/l, 33 g lipid/l, 54 g protein/l, and a sufficient amount of vitamins, minerals, and trace elements. This provided about 1250 kilocalories/l (5330 kj);
• ward-made milk mixture, consisting of 150 g dried skimmed milk/l, 50 g sugar/l, 50 g vegetable oil/l, and 25 g protein (3 raw eggs)/l, in addition to flavouring (vanilla, chocolate, or others) and multivitamins with minerals and trace elements. This mixture, which provided about 1000 kilocalories/l (4664 kj), was used infrequently as an alternative choice when we had insufficient ready-made (commercial) feeding diet.

Using the Curreri formula,1 the daily caloric requirement was calculated for each patient as 25 times the body weight in kilograms plus 40 times the percentage of total BSA burned.

The enteral feeding for both groups was usually started on the second day post-burn and stepped up gradually to the maximum tolerated by the patient, in order to approach the daily caloric requirement calculated. <% createTable "Fig. 2","Parenteral nutritional preparations used for supplementation.",";500 ml dextrose 25% providing 5659 kilocal;500 ml fat emulsion 10%;500 ml amino acids 5%@;50 ml human albumin 20% or 250 ml plasma protein 5%;;","",4,300,true %>

The parenteral nutrition given to patients in group A as a supplement to their main enteral nutrition (Fig. 2), included 500 ml dextrose 25% (Dextrose Inj.®), 500 ml lipid emulsions 10% (Lipofundin® MCT/LCT) containing medium- and long-chain triglycerides in equal proportions, 500 ml amino acids 5% (Aminoplasmal® LS-5) with 10% sorbitol, and either 50 ml human albumin 20% or 250 ml plasma protein 5%. This parenteral support, providing 1329 kilocalories (5650 kj), was usually administered via a large peripheral vein. In all cases, it was commenced on day 4 post-burn and interrupted for one day after every four days of support.

Blood sugar, serum urea, and electrolytes were measured daily, while liver function tests and the blood picture, including the lymphocyte count, were monitored twice a week; total serum protein and body weight were recorded once a week. As the facilities of our lab for measuring various nutritional profiles are limited, we used changes in the patients’ body weight and total serum protein to assess and monitor the effectiveness of the nutritional support given.

Results

Good tolerance without any major complications was observed in most of the patients. One patient, a 60-yr-old male in group B, had infrequent vomiting and diarrhoea.

Tables I and II summarize the effect of the different nutritional supports on patients in groups A and B respectively. There were differences between comparable patients in the two groups, and the reduction in the mean body weight of patients in group A (2.6 kg) was slight compared with that of patients in group B (7.0 kg). Also, the mean value of total serum protein of patients in group A remained at nearly normal level (6.21 gm/dl) compared with that of group B (5.49 gm/dl); the difference between the mean values of the two groups was statistically significant (p < 0.05).

Discussion

It is well known that extensive burn injuries elicit the most pronounced metabolic response to trauma.2 A number of papers have discussed the physiological derangements leading to this hypermetabolic state3-21 and the role of nutrition in the management of severely burned patients,18,19 as well as ways of supplying nutritional needs.3, 22-24 The great value of the enteral route in feeding severely burned patients is widely appreciated, and we agree that enteral nutrition gives less trouble to burned patients and recommend its early commencement.3,8,23,24 Nevertheless, a combination of factors - loss of appetite, nasogastric-tube intolerance, disturbances of gastrointestinal motility, pain, surgical intervention, and infection, all of which may accentuate the patient’s unwillingness or inability to take or absorb sufficient food at a time when caloric and protein requirements are considerably increased - means that the optimization of severely burned patients’ nutritional state by means of enteral support alone is very hard to achieve. On the other hand, the exclusive use of total parenteral nutrition (TPN), in lieu of enteral nutrition, to support such patients has been strongly opposed by many physicians. It has been reported25 that TPN increases the production of tumour necrosis factor in response to endotoxin exposure and that there is a significant reduction in helper/suppressor T lymphocyte ratio in patients kept solely on TPN and an increase in their mortality rate;26,27 it has also been shown22 that the use of TPN results in atrophy of the intestinal mucosa, although the addition of glutamine to the parenteral preparation has been proved to protect and preserve small bowel mucosa;28 and it has also been reported that severely burned patients on TPN may have an excessively high insulin level11,12 and that therefore they may be unable to generate a lipolysis (ketogenesis) and thereby limit protein catabolism in response to stress.11-16, 29

The current study has shown that parenteral supplementation of enteral nutrition is safe, gives better results in minimizing the negative nitrogen balance, and to a great extent preserves the nutritional integrity of severely burned patients. We have not encountered any major problems associated with parenteral infusion,30,31 which may be due, in part, to our practice of giving the patient one day off (without infusion) after every four days of supplementation, periodically, and also to our avoidance whenever possible of the use of a central line. On the other hand, we must admit that the limited number of patients in this series may have reduced the likelihood of the appearance of some possible complications: it is also difficult for us to say whether such parenteral supplementation is appropriate in children below 10 years of age. We therefore conclude that in view of our limited experience further similar studies are called for in order to ascertain and test the value of this feeding regime before it can be proposed as a nutritional supporting option.

RESUME. Les Auteurs présentent les résultats de leur expérience avec l’emploi du support nutritionnel entéral supplémenté parentéralement. Ils ont observé l’utilité de ce type de support pour préserver l’équilibre de l’azote et pour maintenir l’intégrité nutritionnelle des grands brûlés. Trente patients atteints de brûlures (18 mâles et 12 femelles) ont été sélectionnés pour cette étude prospective entre les patients qui présentaient une superficie brûlée étendue (20-50%) hospitalisés pendant une période de 5 ans (1995-2000) dans l’unité de brûlures située auprès de l’Hôpital Ajala à Benghazi (Libye). La sélection a été réalisée pour former deux groupes de patients comparables. Les patients ont été assignés au hasard à un type de support nutritionnel: ou le support entéral supplémenté parentéralement (groupe A) ou le support entéral seul (groupe B). A part la nutrition, la gestion des brûlures était identique dans les deux groupes. Pour évaluer l’efficacité du support nutritionnel donné, les Auteurs ont utilisé les modifications du poids corporel des patients et la protéine sérique totale. La comparaison des résultats obtenus a démontré des différences significatives entre les deux groupes pour ce qui concerne leur réponse nutritionnelle.

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