Supportive Therapy in Burn Care National Institutes of Health
Consensus Development Conference Statement
November 10-11, 1978
This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong. For reliable, current information on this and other health topics, we recommend consulting the National Institutes of Health's MedlinePlus http://www.nlm.nih.gov/medlineplus/.
This statement was originally published as: Supportive Therapy in Burn Care. NIH Consens Statement 1978 Nov 10-11;1(9):35-38.For making bibliographic reference to the statement in the electronic form displayed here, it is recommended that the following format be used: Supportive Therapy in Burn Care. NIH Consens Statement Online 1978 Nov 10-11 [cited year month day];1(9):35-38.
On November 10 and 11, 1978, the National Institute of General Medical Sciences, with the cooperation of the American Burn Association, sponsored a
Consensus Development Conference on Supportive Therapy in Burn Care. Topics in five major areas were considered by the participants. These included: establishment of the appropriate parameters for the optimization of fluid resuscitation in the severely burned patient, analysis of the major methods for primary control of infection, review of the most reliable techniques for the maintenance of nitrogen balance, discussion of the mechanisms available for determining the extent of smoke inhalation, and resolution of the appropriate time during burn therapy for the use of excisional therapy. In addition two ethical issues were considered: under what conditions, if any, of burn injury would it prove futile to attempt resuscitation; and, considering their role in lowering resistance to infection, when would it be justified in administering steroids in response to smoke inhalation. Each question was debated by a panel of experts involved in the research and practice of burn medicine. Discussants from the audience, selected in advance of the meeting, attempted to probe and question the scientific arguments. At a plenary session, the moderator of each panel presented a series of consensus recommendations to the audience. After discussion, many of the panel summaries were amended to reflect the wider consensus among all participants at the conference.
The technical charge to the conference was given by Dr. Emilie Black, Assistant Director for Clinical Research of the NIGMS. In her introductory remarks she defined technical consensus development as a process that is designed to force the traditional laissez-faire attitude of science in a new direction in which there is an attempt to validate the safety and efficacy of clinically relevant knowledge. It's designed to facilitate agreement both on those approaches or treatments that appear most effective at present and on future research directions for issues that cannot be easily resolved. Conversely, technical consensus is not expected to yield definitive statements on health care that do not also permit the introduction of alternative technologies.
In responding to the charge the moderator of each panel first summarized those areas in which consensus was reached and then described those issues where the panelists failed to reach agreement or where they concluded that further research was necessary. The plenary session was begun with a discussion of the conclusions reached by the panel on FLUID RESUSCITATION. The panelists agreed that for effective resuscitation the keystones of therapy are sodium and water. Treatment should be begun with a balanced salt solution, such as Ringers lactate. Colloid may be incorporated into this treatment regime. Many felt that its best use might be after 24 hours. There was general agreement that the total fluid replacement should be largely within 24 hours and range between two and four milliliters per kilogram percent burn, with the rate of administration striking a balance between potential overload and the need to achieve physiological repair. The panel emphasized that although there was a need for modulation and individualization in treatment, formulas do play a vital role by serving as a standardized baseline from which adjustments and deviations can be made. They concurred that generalized cardiovascular response as including the patient's sensorium and urine output (30-50 ml/hour in adults) should be employed to monitor response to resuscitation.
With regard to the question of efficacy of fluid resuscitation in patients with burns over 70% of the body area, the panel stated that physicians had an ethical and moral responsibility to initiate therapy on all patients. Physical and/or emotional shock in the burn patient make it impossible for the victim to contribute to the early decision-making process.
They suggested that future directions in research include: the effect of resuscitative regime on the post-resuscitatory phase of burn illness, more studies on the composition, tonicity, and sodium content of resuscitating fluids, and elucidation of the factors leading to altered vascular permeability, which causes the need for fluid resuscitation.
The second panel, which was concerned with the response to infection, emphasized the need to test prospective modalities and regimes under circumstances which allow a clearer documentation of benefit. They noted that several classes of patients, namely those at both extremes of age, those with very deep, full-thickness injury, and those with serious associated diseases are at the greatest obvious risk, but that other patients may become abnormal in some physiologic way during the course of treatment.
The panel stressed the value of a basic inquiry into the normal mediators of inflammation. Similarly they recommended consideration in much greater detail of ways to stimulate host defense mechanisms, both of the non-immune and immune or specific type. The group concurred with the findings of the metabolism panel (vide infra) that nutrition is a significant factor in combating both systemic and local infection, while at the same time noting that the local wound and its ability to withstand infection may be influenced by the characteristics of the fluid resuscitation scheme chosen.
There was also consensus reached about the need for more research in the areas of multiple system interactions and their utility in predicting host response to infection, employment of immunosuppressive substances, especially with the danger of variable response, development of vaccines which would permit specific immune protection from a variety of pathologic microorganisms, and the possible role of non-bacterial opsonization of particulate matter in amelioration of remote vital organ failure.
On the other hand, the panel could not reach a solid consensus about the applicability of barrier systems or about the specific role of dressings in the control of infection. Systemic antibiotics were discussed in some detail and although there was broad agreement regarding their use in established burn wound sepsis or in the circumstances of remote organ infection, initial penicillin in particular, posed a problem. In analogous fashion, the panel concurred on the beneficial effect of topical agents. There was only disagreement as to whether the respective agents needed to be classified for prophylaxis and/or therapy.
The third question, regarding the development of nutritional requirements to overcome the metabolic effects of burn injury, was addressed in several ways by the panelists. The group first reviewed those areas of biochemical response to burns in which there was consensus about the mechanism of action. Thus, in the area of carbohydrate metabolism, there appears to be increased gluconeogenic flux associated with an increase in glucagon, glucocorticoids, and catecholamines. There is a variable response of insulin. The protein catabolic state is characterized by increased urinary nitrogen excretion and the requirement for both increased nitrogen and caloric intake to achieve nitrogen balance. There is exaggerated nitrogen catabolism and weight loss whose magnitude is curvilinearly related to the extent of injury. The hypermetabolic state following burn injury is the result of an intrinsic metabolic drive which is mediated by humoral factors.
With regard to therapeutic applications for the treatment of the metabolic deficits in burn injury, the panel concurred that burn patients who require nutritional replacement are those who either have greater than 20% total body surface burn, pre-injury nutritional deprivation, severe endocrine, pulmonary or septic complications, or suffer greater than 10% decrease in pre-burn body weight during hospitalization. Nutritional replacement should be started as soon as functional G.I. tract motility is demonstrated and at latest by the fourth post burn day with optimal caloric requirements administered by the seventh day. The group recommended in order of priority the enteral route and if necessary supplemented by the peripheral vein for administration of amino acid-fat emulsion. The central vein was to be employed for glucose-amino acid solutions only when the enteral route was not available. In adults the general formula 25 kcal/kg body weight plus 40 kcal/percent total body surface burn was regarded as an acceptable method for estimating the extent of nutritional replacement providing that readjustments are made for body weight changes, septic complications, and decreased host resistance. A specific formula could not be agreed upon for children.
Finally the panel suggested a number of topics as appropriate for future research. In therapeutic applications these included more accurate nitrogen caloric ratios, effect of trace elements, minerals and vitamins in nutritional therapy, and the use of alternative amino acid mixtures. In addition, there were recommendations for studies on the definition of insulin resistance in burns, hormonal effects on carbohydrate and protein metabolism, and the metabolism of both endogenous and exogenous (parenterally administered) fat metabolism.
The topic dealt with by the fourth panel concerned both the determination and treatment of injury caused by SMOKE INHALATION. The group began with a categorization of the types of injury, which can include either an increase in the levels of carbon monoxide, damage to the airway, lowering of oxygen levels, or development of a form of respiratory distress syndrome which results from the combined insult of the airway and cutaneous injuries. They agreed that the variety of insults requires a more precise, universally accepted classification scheme.
They then considered the techniques currently available for the diagnosis of smoke inhalation. The choice of technique will depend upon the type of injury with relatively simple tools such as the laryngeal mirror being used for upper airway injury. There was a consensus that a concentrated research effort must be launched for the early detection of parenchymal airway injury. Fruitful lines of approach include measurements of the distribution of ventilation profusion ratios and the techniques of compartmental analysis of nitrogen wash-out and inert gas elimination.
In analyzing the need for steroids in treating smoke inhalation injury, the panel took note of a recent study in which steroid treated patients suffered a mortality rate four times as great as the control group. They concurred that the use of steroids is not indicated for any degree of smoke inhalation at the present time.
Profitable directions in research include therapeutic approaches to combine airway and cutaneous injuries, continuation of current investigative programs into the disruption of the microcirculation and particularly the effect of damage to the pulmonary endothelial cell on the evolution of the late forms of smoke inhalation injury.
The last panel reviewed the role of excisional therapy in minimizing the metabolic and bacteriological complications attendant upon the creation of a large unhealed wound. They noted that if after thermal injury, recovery of skin function does not take place within a matter of a few weeks through healing of the partial thickness component and wound closure through skin grafting, the patient is quite likely to die. Thus, logically, it follows that the burn illness can be terminated by prompt burn wound closure. In practical terms this means the early excision of all deep components of the burn and skin grafting with autografts.
In discussing how best to treat deep burn wounds, the panel agreed that assessment of burn depth is critical. They found that vital dyes have not been of help and that although thermography and ultrasound can be useful in mapping the area and depth of injury these methods are tedious, cumbersome and impractical at present. Most superficial burns (i.e., second-degree) can be accurately recognized.
There was a general consensus that for deep thermal injury excision should be carried out when the patient is hemodynamically stable. However, excisional therapy was not recommended for the patient who has associated smoke inhalation injury or who has other injuries in addition to the burn.
The most effective technique at present is sequential, or layered, excision. The method allows the surgeon to sculpt the wound and minimizes the loss of viable tissue although there is considerable loss of blood. Excision of fascia should be reserved for deep third degree burns of large extent and can be carried out with conventional scalpel or electrocautery. Soon after burn wound excision, grafting is carried out. Meshed autograft expanded to at least three to one should be used to the extent possible. Cadaver allografts, amniotic membranes, or xenografts can also serve as useful biologic covers. The technique of allografting using HLA compatible live donors coupled with the use of immunosuppressive agents appeared promising but the panel recommended that it only be attempted in a specialized burn center. In all cases excisional therapy should be done only under controlled circumstances by skilled surgeons.
In assessing promising avenues of research, the panel pointed to the potential of chemical debridement which may obviate the requirement for anesthesia while permitting an accurate determination of burn wound depth. They agreed that the development of hemostatic scalpels is to be encouraged.
In summary the panels were able to reach consensus in a number of areas that directly affect the type of treatment provided to the severely burned patient. In addition they defined several approaches and technologies that appeared to hold great promise.
The National Institute of General Medical Sciences, acknowledging its role as a catalyst in the technology transfer process, will attempt to disseminate the conference conclusions as widely as possible. Both lay and technical articles will appear in other magazines and journals. The edited proceedings of the conference, including the complete summaries from each panel, will be published within six months. In addition, tapes will be made available through the auspices of the National Library of Medicine. Finally, members of the Institute staff together with several of the panelists will discuss the findings of the conference at a session to be held at the annual meeting of the American Burn Association, with the view toward revising the Guide to Initial Management of Burns prepared by the Subcommittee on Burns, Committee on Trauma, American College of Surgeons.
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