Cent Of Body Surface Area Research Articles

The effect of heparin on dermal ischaemia after burning

Heparin has been said to improve microvascular perfusion in the burn wound. Using 75°C, 10 s, 5 per cent body surface area guinea-pig scald burns, histology was studied and the amount of dermal perfusion was measured periodically after burning. Microcirculatory dermal perfusion was evaluated after indian ink injection. Untreated control animals were compared with animals treated with topical heparin, animals treated with systemic heparin and animals treated with both topical and systemic heparin. Immediately and up to 2 h post burn there was vascular filling to 85 percent thickness of the dermis in all animals. By 8 h, the dermal perfusion had fallen to 40 per cent dermal thickness and at 24 h no dermal perfusion occurred. At 24 h only the subdermal vessels contained indian ink. The animals' wounds which were allowed to heal showed no regeneration of dermal appendages, grossly or microscopically. In this model, heparin failed to prevent progressive dermal ischaemia or to allow regeneration of dermal appendages.

Elevated cortisol levels and changes in thymus metabolism in burn trauma

Burns greater than 15–30 per cent body surface area (BSA) are associated both with an acquired immunologic deficiency in the cell-mediated thymus-regulated immunity and a significant increase in the glucocorticoid levels. Since the majority of thymus lymphocytes undergoing maturation are cortisol-sensitive, we have investigated the synthesis of nucleic acid and proteins in the thymus in relation to cortisol elevation during the first week following a 30 per cent third-degree scald burn in young guinea-pigs. At various times post burn thymus cell suspensions from burn and control animals were incubated in vitro with [ 3H]-thymidine, [ 3H]-uridine or [ 3H]-amino acid mixture to assess the synthesis of DNA, RNA or proteins respectively. The synthesis of macromolecules was measured in terms of radioactivity incorporated into acid-insoluble material and normalized to the DNA content. Parallel measurements of 24 h urinary ‘free’ cortisol levels were performed by radioimmunoassay. Observed decreases to 64 and 83 per cent of the control values in DNA and RNA synthesis respectively, at 6 days post burn, are independent of the changes in the precursor uptake. The decrease in nucleic acid synthesis is associated with significant elevation in both urinary 24 h ‘free’ cortisol levels (185 per cent control) and cortisol levels in thymus (approx. 300 per cent control). These results suggest that changes in thymus metabolism associated with elevated cortisol levels could contribute to suppression of T lymphocyte production or maturation and result in a relative immunodeficient state.

Increased rates of whole body protein synthesis and breakdown in children recovering from burns.

The rates of whole body protein synthesis and breakdown were determined, with the aid of a constant administration of [15N]glycine, during recovery in 11 acutely burned children, involving a total of 24 studies. Eleven studies were also conducted in seven healthy children before and after reconstructive surgery. Rates of whole body protein synthesis and breakdown, expressed as g protein/kg body weight/day, were significantly (p less than 0.05) and positiviely correlated with per cent body surface area total burn, per cent third-degree burn, and per cent open wound. These rates (synthesis, 7.1 +/- 2.1 g protein/kg/day; breakdown, 6.3 +/- 1.8 g protein/kg/day) were 80 to 100% greater (p less than 0.05) in patients with total burns greater than or equal to 60%, as compared to patients with less than 25% total burns or to the surgical patients. Because of the high energy cost of protein synthesis, it is proposed that an increased whole body protein turnover is partly responsible for the reported elevations in rates of heat production occurring in patients recovering from thermal injury.

An unusual case of low α1 antichymotrypsin in a burned patient

Measurement of the level of serum α 1 antitrypsin ( α 1AT) and α 1 antichymotrypsin ( α 1ACT) in a 31-year-old male with a 35 per cent body surface area burn showed the patient to have low levels of α 1ACT on admission to the Wessex Regional Burns Centre. The rise in the level of this protein was depressed by comparison with other patients sustaining comparable injuries and the level of the protein returned to about 50 per cent of the normal value. The α 1AT level was also depressed and it is possible that this patient has a genetic deficiency of both α 1AT and α 1ACT.

Nutritional requirements and parenteral nutrition

ENERGY REQUIREMENTS In the context of this discussion it is appropriate to think of a big burn, one of between 30 and 60 per cent of body surface area, where there are likely to be quite extensive areas of full-thickness involvement. In burns of this severity, metabolic rate changes have an important impact on the outcome. Clearly, similar changes occur with smaller burns, but these are of a different order of magnitude and therefore proportionately less important. In a big burn, the metabolic response to injury, already the subject of so much discussion in theliterature, the effect of integumentary damage leading to energy loss from evaporative cooling of water and the not infrequent occurrence of infection leading to fever all contribute to an increase in energy expenditure. The net result is an increase in metabolic rate which will vary with the extent of burn, the stage of the reparative process and the environmental conditions in which the patient is placed (Barr et al., 1968). In terms of energy cost this may amount to much more than 5000 calories per day in an adult weighing 65 kg or more and burned over an area greater than 40 per cent of his body surface (Wilmore, 1972). Comparative figures for the energy requirements in burns are shown in Table I. In normal health there is ample information about the energy expenditure of people in different activities and there is no doubt about how many calories are required in different circumstances to maintain balance. It is more difficult to define protein needs in health. The answer must lie somewhere between the excessive consumption of animal protein found in the affluent industrialized nations and the often extremely poor intake in people in many of the emerging nations. Monroe, who has contributed so much to our knowledge

Fungal infection in burn patients: Results of using 5-fluorocytosine (flucytosine)

Fungal infection and use of 5-fluorocytosine were studied prospectively among burn patients receiving multiple antibiotics. From 22 out of 23 patients positive cultures for Candida were obtained. Cultures from the mouth and rectum became positive first. Averaging 6 days later, 16 patients had positive urine cultures. Candida in urine was the best way to detect systemic candidiasis. Nine patients received 5-fluorocytosine. Although this drug did not influence survival among patients with burns of less than 59 per cent of body surface area, it prevented death from disseminated Candida infection among patients with burns of greater than 60 per cent body surface area. Patients with large surface burns receiving multiple antibiotics should have prophylaxis against fungi. If Candida is detected in urine, systemic treatment should be given. 5-Fluorocytosine is a safe and effective systemic drug for this purpose.

F(ab')2-like fragments from severely burned patients provide a new serum immunoglobin component.

INTEREST in immunoglobulin fragments in serum centres around their antigenic sites which stimulate autoantibody1, and the insight they provide into the metabolism of immunoglobulins. They also have the potential to alter host immune defence mechanisms. For example, the F(ab′)2 fragment prepared in vitro from IgG is less effective than intact IgG in protecting animals injected with pathogens2, in aiding phagocytosis3,4 and in clearing bacteria from the blood stream2,5. Also, F(ab′)2 fragments are non-cytotoxic in the presence of complement6,7 and enhance the growth of tumours8,9. Because severely burned patients have larger than normal concentrations of proteolytic enzymes10 and immunoglobulins in their serum11–13, we regarded them as potential models for in vivo degradation of immunoglobulin, and examined serum from forty patients with 3–70 per cent body surface area full-thickness burns for immunoglobulin fragments. The following report identifies for the first time a serum F(ab′)2-like fragment in severely burned patients.

Myocardial function following thermal injury.

Several investigators have suggested that a defect in myocardial function occurs in the dog following severe thermal burn. A study was therefore undertaken in which myocardial contractility was measured before and after burn. The left ventricular function curve was used as an index of contractility. Ventricular function was measured immediately before and 30 minutes following 30 per cent body surface area burn in 25 dogs, and before and after a sham burn in 13 control dogs. It was found that the burn produced a significantly greater impairment of myocardial contractility than did the sham burn. The mechanism by which the burn produced this alteration in contractility was not apparent from the results of this study.

Observations on the Effects of Blood, Plasma, and Sodium Salt Solutions in the Treatment of Extensive Burns

T HE ffuid therapy of extensive full-thickness burns has been a subject for investigation and controversy for the past thirty years. UnderhiII’ emphasized the fluid 10s~; BIaIock2 believed this to be primariIy Ioss of pIasma. On the other hand, Davidson3 described a disturbance in sodium chloride metaboIism. The therapeutic roIe of sodium in burned mice was discovered by RosenthaI in numerous experiments which revealed the critica importance of an adequate volume of administered fluid. These factors were then explored in humans in preliminary clinica triaIs of the use of sodium saIt soIutions by Fox. 5 Whole blood was then combined with eIectroIyte soIutions in burned dogs by Moyer,6 and Abbott? utilized this combination in humans. McCarthy and Parkins@ and hlcCarthy8b in Ravdin’s Iaboratory, investigated aIbumin, saline, dextrose in water and various combinations with blood, pIasma and sodium Iactate in burned rats. Based on observations in humans and dogs, Evans9 proposed a formula combining bIood, pIasma or plasma extender, saline and dextrose in water. In a11 of these investigations the experimenta conditions, species of anima1 utiIized, criteria of efficacy and basis for evaluation have been different. In most instances the investigators have not compared their studies with those of earIier investigators. When the obvious hazard of extrapoIating resuIts of anima1 experimentation to man is added, it becomes apparent that a sotid foundation for prescribing a formuIa for the treatment of fuII-thickness extensive burns in man does not exist. AccordingIy, three years ago we attempted to organize a comparative study of the Buid therapy of burns in patients. After consultation with numerous experts it was decided to Iimit the study to comparison of two treatment scheduIes: the combination of bIood, pIasma or plasma extender, saIine and dextrose in water versus sodium salt soIutions onIy. The period of comparative study was to extend over the first three days from the time of injury; subsequentIy bIood was to be used as IiberaIIy as required in both groups of patients in preparation for skin grafting. Patients were pIaced in each group on the basis of strict alternation. In both groups measurements of bIood and urine composition were made at frequent intervaIs. The exposure method of Iocal treatment was used wherever feasibIe in both groups. Patients were observed most carefuIIy; had those receiving eIectroIyte onIy shown any need for blood and plasma, these were to be utiIized. The number of patients made avaiIabIe for this study was much smaIIer than anticipated; but the program has been continued and with the passage of time a Iarger and proportionateIy more vaIuabIe series of study cases will be achieved. Because of the Iimited number of patients it is essentia1 to recognize the preIiminary nature of this report and to understand that we are unabIe to draw any statisticahy vaIid conclusions at this time. We also conducted a detaiIed survey of approximately 140 patients with extensive burns, of whom 100 died. The combined clinical materia1 raises many important questions which we present for your consideration. It is apparent from our experiences and those of others that extensive fuII-thickness burns of more than 40 per cent of body surface area (BSA) are frequentIy fata1, and unfortunatety many patients with Iess extensive burns

Observations on the effects of blood, plasma and sodium salt solutions in the treatment of extensive burns

T HE ffuid therapy of extensive full-thickness burns has been a subject for investigation and controversy for the past thirty years. UnderhiII’ emphasized the fluid 10s~; BIaIock2 believed this to be primariIy Ioss of pIasma. On the other hand, Davidson3 described a disturbance in sodium chloride metaboIism. The therapeutic roIe of sodium in burned mice was discovered by RosenthaI in numerous experiments which revealed the critica importance of an adequate volume of administered fluid. These factors were then explored in humans in preliminary clinica triaIs of the use of sodium saIt soIutions by Fox. 5 Whole blood was then combined with eIectroIyte soIutions in burned dogs by Moyer,6 and Abbott? utilized this combination in humans. McCarthy and Parkins@ and hlcCarthy8b in Ravdin’s Iaboratory, investigated aIbumin, saline, dextrose in water and various combinations with blood, pIasma and sodium Iactate in burned rats. Based on observations in humans and dogs, Evans9 proposed a formula combining bIood, pIasma or plasma extender, saline and dextrose in water. In a11 of these investigations the experimenta conditions, species of anima1 utiIized, criteria of efficacy and basis for evaluation have been different. In most instances the investigators have not compared their studies with those of earIier investigators. When the obvious hazard of extrapoIating resuIts of anima1 experimentation to man is added, it becomes apparent that a sotid foundation for prescribing a formuIa for the treatment of fuII-thickness extensive burns in man does not exist. AccordingIy, three years ago we attempted to organize a comparative study of the Buid therapy of burns in patients. After consultation with numerous experts it was decided to Iimit the study to comparison of two treatment scheduIes: the combination of bIood, pIasma or plasma extender, saIine and dextrose in water versus sodium salt soIutions onIy. The period of comparative study was to extend over the first three days from the time of injury; subsequentIy bIood was to be used as IiberaIIy as required in both groups of patients in preparation for skin grafting. Patients were pIaced in each group on the basis of strict alternation. In both groups measurements of bIood and urine composition were made at frequent intervaIs. The exposure method of Iocal treatment was used wherever feasibIe in both groups. Patients were observed most carefuIIy; had those receiving eIectroIyte onIy shown any need for blood and plasma, these were to be utiIized. The number of patients made avaiIabIe for this study was much smaIIer than anticipated; but the program has been continued and with the passage of time a Iarger and proportionateIy more vaIuabIe series of study cases will be achieved. Because of the Iimited number of patients it is essentia1 to recognize the preIiminary nature of this report and to understand that we are unabIe to draw any statisticahy vaIid conclusions at this time. We also conducted a detaiIed survey of approximately 140 patients with extensive burns, of whom 100 died. The combined clinical materia1 raises many important questions which we present for your consideration. It is apparent from our experiences and those of others that extensive fuII-thickness burns of more than 40 per cent of body surface area (BSA) are frequentIy fata1, and unfortunatety many patients with Iess extensive burns