Medical Science Publication No. 4, Volume II
WEDNESDAY MORNING SESSION
28 April 1954
MODERATOR
STANLEY M. LEVENSON, M. D.
NUTRITION OF THE INJURED*
STANLEY M. LEVENSON,M. D.
Last week, in the discussions of the care of patients with severe battlewounds and renal failure, mention was made of the serious nutritional problemsencountered in these patients. You will recall that weight losses of 20to 30 pounds in 2 to 4 weeks were frequent and losses up to 45 pounds inthe same period of time were not uncommon (table 1).
Table 1. Wound Healing in Patients with RenalDysfunction
Group | Number of patients | Weight loss (lbs.) | Number of deaths | Average day of death |
Patients with unimpaired wound healing | 11 | 20-30 | 0 | ----- |
Patients with impaired wound healing | 31 | 30-45 | 16 | 15 |
Malnutrition was not limited, however, to wounded soldiers with concomitantrenal failure but was observed in many seriously wounded patients withrenal failure. In general, the more severe the injury, the greater thenutritional disturbance. Where malnutrition developed, a number of complicationsensued: Gastrointestinal and hepatic functions were impaired, wound healingwas delayed, infection was more serious, morbidity was prolonged and mortalitywas increased.
Several factors are involved in the development of malnutrition followinginjury. Derangements in water, electrolyte, vitamin, fat carbohydrate andprotein metabolism occur. Characteristically, an injured individual excretesexcessive amounts of nonprotein nitrogen in his urine for 3 to 7 weeksfollowing injury. During this time he is in negative nitrogen balance andis gradually losing body protein. The intensity and duration of this periodof protein depletion depends on a number of factors, among which are theextent of the injury and the state of the individual at the time of injury.However, we still are not entirely clear as to what the basic mechanismis for
*Presented 28 April 1954, to the Course on Recent Advances in Medicine and Surgery, Army Medical Service Graduate School, Walter Reed Army Medical Center, Washington,
D. C.
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the metabolic derangements after injury. There are a number of factorsinvolved, including imbalance of endocrine activity, immobilization andreduced dietary intake. The possibility that a disturbance in the metabolismof one or more of the essential amino acids is one of the important factorsin the pathogenesis of the increased catabolism following injury was suggesteda number of years ago by various investigators. However, there have beenno conclusive data in this regard. Plasma amino acids have been littlestudied in the past for lack of appropriate methods. In the past few years,with the advent of ion exchange chromatography, it has become possibleto separate quantitatively each of 18 amino acids, and to study their quantitativerelations to the other plasma NPN components.
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We have been investigating these problems in battle injuries with andwithout associated renal failure. Samples of plasma were collected at the46th MASH and at the 11th Evacuation Hospital. These samples were immediatelyfrozen and shipped in the frozen state to the Army Medical Service GraduateSchool.
It has been previously thought that trauma of various types is followedby a general rise in plasma amino acids. We have found that such is notthe case. For example, in patients with battle wounds and renal dysfunction,the total nitrogen of the free amino acids remained very close to normal,in spite of extremely high NPN's-some higher than 400 mg. per 100 cc. (fig.1). Examination of the individual amino acids reveals that each of theplasma amino acids reacts to injury of the organism in its own fashion(figs. 2, 3, 4, 5, 6).
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Some of these patients were dialyzed by the artificial kidney. Analysesdone on plasma taken immediately before and after dialysis indicate thata homeostatic mechanism operates to keep the plasma amino acid concentrationsextremely constant despite the washing-out process of dialysis (fig. 7).
Although the total free amino acid concentrations remain near normal,large quantities of an amino acid conjugate characteristically appear inthe plasma of patients with injury and renal dysfunction. On hydrolysis,this component consists of glycine, threonine and glutamic acid, in normalindividuals. Amino acids appear on hydrolysis which are not found in measurableamounts in the normals
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(fig. 8). The ratios of the amino acids of the conjugates may vary frompatient to patient, and from day to day in the same patient, suggestingheterogeneity of the substance (fig. 9). Further studies are in progressto determine the nature of this component, its metabolic origin, and itsphysiologic activity.
From the practical point of view, we know that one of the most importantfactors which influence the metabolic response to injury and the extentof subsequent nutritional depletion is the food intake. The intake of theseriously injured patient is normally decreased in the early period followingtrauma and this accentuates the nitrogen loss. If the dietary intake ofthe seriously injured individual were maintained at an adequate level,beginning shortly after trauma, many
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of the problems associated with the development of malnutrition wouldbe averted. This was not usually obtained during the Korean conflict.
Situation at the MASH Level
The following remarks are based on observations made at the 46th MASHduring January and February 1953. The majority of patients remained atthe MASH for only a few days, and were chiefly on
intravenous fluids (blood, dextran, glucose, water, saline) during thistime. A lesser number of patients remained 7 to 10 days. Adequate nutrientintake was often not provided these patients. Neither special foods norindividuals with special knowledge of dietetics were available. The foodoffered them was the same as that prepared for the MASH personnel and wasoften cold by the time it was served to the patients. So-called "nourishingdrinks" (cocoa, fruit juices, etc.) were offered most patients betweenmeals.
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Vitamins were not given during the preoperative period. In the postoperativeperiod, patients on oral intake were occasionally given one or more multivitamincapsules daily. Those patients receiving intravenous fluids were given500 mg. of vitamin C and 50 mg. of thiamine once or twice a day. VitaminK preparations were occasionally given when there appeared to be a specificindication, for example, a decreased plasma prothrombin concentration.This type of vitamin therapy is imbalanced.
It was the impression of the nurses and the staff that most of the patientsate fairly well, but it would appear that the patients who
ate well were the ones with the less severe injuries; the patients withextensive injuries usually ate poorly. A close check of the dietary intakeof some severely injured patients revealed a totally inadequate intake.Body weights were measured only occasionally, but some patients apparentlylost as much as 20 pounds in 10 days. The neurosurgeons were particularlyfirm in their conviction that serious weight loss occurred very rapidlyin their patients.
Experiences at the Renal Center
As already mentioned, serious malnutrition developed rapidly and wasan important complication in the patients with severe battle
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wounds and renal failure. All these patients lost weight rapidly. Impairmentof wound healing and mortality paralleled weight loss. What the weightloss specifically represents in terms of body tissue, water, fat, etc.,is not known. However, data of apparent nonprotein nitrogen productionobtained in a few patients reveals a very large nitrogen "loss."In one patient, this amounted to about 45 gm. N per day. This representsthe daily breakdown of 2.5 lbs. fat-free tissue.
Providing an adequate nutrient intake was a very difficult problem inthese patients. Many were unable to take food orally over long periodsof time. Parenteral alimentation was limited by the policy of rigid fluidrestriction during the period of oliguria which in some cases persistedfor 2 or 3 weeks. The problem was futher complicated by the policy of noprotein administration during this same period. This was based on the considerationthat in renal failure administration of dietary protein may be harmful.Consequently, the nutrient intake of these patients was very low and grosslyinadequate. The
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average daily caloric intake when the patient was on only parenteralfluids was 500 to 1,000 calories per day-supplied as 25 or 50 percent glucose.The only parenteral vitamin preparations available were vitamin C (in 500mg. ampules), thiamine chloride (50 mg./cc.), and various vitamin K preparations.As mentioned, this resulted in a markedly imbalanced vitamin intake.
It is not possible to determine the exact oral dietary intake of thesepatients from the available records, but it appears that the oral foodintake was low until long in the convalescent period. Both the diminishedcaloric and protein intake of these patients undoubtedly contributed totheir rapid body tissue loss. This may be illustrated by table 2 whichdepicts data on two patients of similar age with almost identical injuries.The injuries were full-thickness burns involving about 12 percent of thebody surface.
Table 2. Effect of Protein Intake on NitrogenLoss Following Injury Cumulative Nitrogen Balance (gm.)
Days | Patient A | Patient B |
1-13 | - 6 | - 110 |
14-25 | - 16 | - 175 |
The patients were placed on constant diets supplying to each 45 caloriesper kilogram body weight but no protein was included in the diet of patientA, whereas patient B ingested 11/2grams of protein per kilogram body weight. The net losses of body nitrogenby the two patients are strikingly different. The patient ingesting proteinhad a net loss of 16 grams of nitrogen in the first 25 days after injury,while the net loss of the patient receiving no dietary protein was 175grams of nitrogen or 10 times as much.
It is clear that inadequate food intake is one of the important factorsin the pathogensis of the malnutrition observed following injury. In anyfuture conflict, attention should be paid to insure adequate dietary intake.
We do not yet know what the optimal intake should be for the severelywounded soldier, but from studies carried out in patients with extensiveburns, it would appear that 4 grams of protein and 55 to 65 calories perkilogram body weight is desirable for the patient with extensive woundsand without renal failure. Now what does this mean quantitatively? It meansthat a seriously injured young adult male weighing 70 kilograms may needabout 275 grams of protein and 4,000 calories daily. About 40 percent ofthe calories ought to be supplied by fat, 30 percent by carbohydrate and30 percent by pro-
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tein. Considerably less protein would, of course, be given patientswith renal dysfunction. We do not know what the optimal requirements areof the patients with serious wounds and renal failure.
The vitamin requirements of the seriously injured are not known, butwe have been using 5 times the normal requirements of the B vitamin, about10 times that of vitamin C, and 1 or 2 times the normal requirements ofthe fat-soluble vitamins.
As far as the routes for feeding patients are concerned, all would agreethat the oral route, when possible, is most satisfactory. No blanket statementcan be made as to how soon after injury oral diets can be started. Thistime would vary depending upon the severity and type of injury. Certainsevere abdominal injuries, prolonged circulatory failure and marked renaldysfunction adversely affect gastrointestinal tract function. In such patientsoral feedings would have to be delayed. In most other patients, diets canusually be started by the second to fourth day after injury. It is wellto take a number of days to increase the food intake gradually since suddenincreases are likely to be followed by gastrointestinal upsets.
Since personnel, equipment and food supplies are limited at the forwardand evacuation hospitals, we feel that a liquid diet is the dietarytreatment of choice under these circumstances.
A palatable formula that contains all of the food elements needed isof course necessary. The ingredients should be simple, inexpensive andwell tolerated. Milk solids are a useful source of proteins. Ordinary milkpowders, whole or skimmed, can be used. Additional carbohydrate, fat, minerals,water and vitamins are added to the protein base to make the preparationsessentially complete. Fat emulsions have proved to be a very useful sourceof fat. They are bland, stable, well tolerated, blend easily and do notseparate from the other ingredients upon standing. For a carbohydrate source,dextrimaltose and lactose are useful. Gavage feedings may be indicatedin instances where the gastrointestinal tract is functioning but the patientfor one reason or another is not ingesting the proper quantity or amountsof food. However, gavage feeding should be undertaken only if a reasonableamount of supervision is possible. Aspiration of the stomach should bedone before each feeding.
Forcing the diet orally or by tube may not always be beneficial. Nausea,vomiting, distention and diarrhea are limiting factors. Further, certainpatients may not be able to take food orally. Under these conditions, supplementationby the intravenous route is indicated. There are certain fundamental considerationswhich hold for intravenous as well as for oral feeding. It is obvious thatthe intravenous preparation should be nutritionally complete and the infusioncarried out at a rate suitable for optimal utilization. At present, itis usually
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impossible to supply adequate calories by the preparations of glucose,fructose and alcohol now available. There is no preparation of fat forintravenous infusion available for general use but it is hoped that sucha preparation will soon be available. When hypoproteinemia is present andthere is a specific indication for raising the plasma protein concentrationquickly (e. g., to reduce gastrointestinal tract edema), the best way ofaccomplishing this is by the infusion of plasma or albumin. Albumin shouldbe used in preference to plasma because of the complications of plasmatherapy (homologous serum jaundice; anemia). If anemia is present, it shouldbe corrected by whole blood or red cell transfusions, but one should notovertransfuse a patient with the expectation of improving the general bodilynutrition of the individual. The nitrogen in the infused compatible redcells will enter the body nitrogen pool only when the infused red cellsare destroyed-and the average survival of normal cells is about 120 days.
The high nutrient intake must be continued at a sufficient level notonly to maintain the patient in nutritional equilibrium but also to restoreat a rapid rate all tissues that have been depleted. Testosterone propionatein doses of 25 mg./day intramuscularly has been used with some successin the late stages of convalescence. Cognizance should be taken of thepossible systemic changes brought about by such therapy when continuedover long periods of time.
