666
DOUGLAS C. HEIMBURGER, M.D. Associate Professor and Director Division of Clinical Nutrition Departments of Nutrition Sciences and Medicine University of Alabama Birmingham, AL 35294
SALIM S. AKRABAWI, PH.D., M.D. Director, Medical Services Mead Johnson Nutritional Group Evansville, Indiana 47721
Response to Letter from Drs. Heimburger and Akrabawi To the Editor: We read with interest the letter of Drs. Heimburger and Akrabawi. They have properly summarized our conclusion that the administration of a new modular tube feeding recipe designed to meet the unique nutritional needs of burn patients supported a better outcome in terms of wound infection and length of hospital stay. We maintain this viewpoint, but are not surprised that such findings would generate concern from the proprietors of Traumacal (Mead Johnson). In burn centers, the severity and predicted outcome from thermal injuries is typically estimated by the age and percent of the body surface area burned.’,’ For this reason, the aforementioned study utilized an experimental design in which diets were tested for efficacy by randomizing patients into three different feeding groups utilizing a random number table stratified for age, institution, and burn size. Patients with burns less than 40%, 40 to 60%, and above 60% were randomized independently into subsets in order to help insure comparability of burn size between the control and experimental groups. Subjects were also blocked into the following age categories: 3 through 11, ages greater than 11 and less than or equal to 21, ages greater than 21 and less than 40, ages greater than or equal to 40 and less than or equal to 65, and finally, greater than 65 years of age. Only patients able to take at least 75% of their targeted calories enterally during the first week after admission were included in the final analysis, because deficiencies caused by early caloric deprivation could have overshadowed any influence of difference in the three feeding
systems.
properly randomized clinical trials, such as the one described, the use of differences in relevant patient characteristics can be considerably reduced, but is not eliminated. For factors which can be measured, treatment group comparability can be tested by some objective criterion (a statistical test), and significant differences can be adjusted for in the analysis stage, sample size permitting. In this study, no significant differences were found between the treatment groups, so subgroup analysis was not undertaken. Additionally, while group 3 In
(Traumacal)
appears to have
a
greater share of smoke
inhalation among the measurable patient factors, there are innumerable clinical effects which theoretically could present unrecognized negative bias in the other two as well, such as alcoholism, drug abuse, preburn malnutrition, natural immunity, severity of inhalation injury, medical history, and associated trauma, to name
groups
a
few.
Certainly, the response to a burn is multifactorial. Outcome can be modified to a great degree by the presence or absence of other disease conditions or associated injuries. We elected not to exclude patients with inhalation injury because it is commonly present in this population and our objective was to determine an optimal diet therapy program for all burns. As we state on page 234 of the original article, &dquo;It is likely that the mortality data partially reflect complications resulting from concomitant pulmonary injury, although both death and smoke inhalation were not statistically different among the three groups.&dquo; Since there were no statistical differences found in smoke inhalation or any other patient factor studied, subgroup analysis or complicated regression techniques (multiple logistic model for qualitative outcomes as primarily measured here) were not undertaken. If significant differences had existed between the treatment groups, these technique(s) would have been appropriate. In summary, the concept of improving outcome by the use of a tube feeding recipe designed to meet the unique nutritional needs of burn patients portends an exciting future in terms of diet therapy. However, a major limitation of the aforementioned clinical trial, as with most studies involving human subjects include the inability to precisely control extraneous clinical effectors. Numerous events and intake variables indeed complicate the process.
MICHELE GOTTSCHLICH, PH.D., R.D., C.N.S.D. GLENN D. WARDEN, M.D. MARK CAREY, M.S. Shriners Burns Institute
Department of Surgery University Hospital Cincinnati, Ohio REFERENCES
I, Flora JD, Bawol R: Baseline results of therapy for burned patients. JAMA 236:1943-1947, 1976 Feller I, Jones CA: The National Burn Information Exchange. The use of a national burn registry to evaluate and address the burn problem. Surg Clin North Am 67:167-189, 1987
1. Feller 2.
Assessing Three Enteral Dietary Regimens for Burn Patients To the Editor: We read with great interest the paper by Gottschlich et al’ in which they describe the use of three enteral
667
dietary regimens for burn patients and assess outcome variables. From the data presented, clear differences in outcome
Lipids and the development of immune dysfunction- JPEN 12:435475, 19S8
existed among the three groups, with the diet
developed by Shriners Burns Institute staff being far superior to the others. Patients randomized to this diet had significantly fewer wound infections and shorter length of stay/percent burn. In addition, these patients had fewer pneumonias (p 0.06), fewer infectious episodes (p 0.07), and fewer deaths (p 0.06). However, we are concerned that although the data in Table III denote no significant differences between the patient groups (except in preburn weights), there may be important clinically relevant differences that did not achieve statistical significance. Specifically, twice as many patients in group 3 suffered smoke inhalation (n=8) than in the other groups (n=4); =
=
=
Table VIII indicates that 50% of deaths were attributed to smoke inhalation injury. Whereas only one of the two deaths in groups 2 (Shriner’s diet) was directly attributed to smoke inhalation, four of seven deaths in group 3 resulted from smoke inhalation injury. Thus it is difficult to conclude that the differences in outcome are due to diet alone; patient differences most likely played a role as well. Regarding the diets themselves, Table I lists the three diets as Osmolite-enriched with Promix; Modular tube feeding; and Traumacal. In reality, all three formulas are modular in nature, as each of the regimens were manipulated. In addition to Promix (whey protein), Osmolite had supplemental multivitamins and single doses of vitamins A, C, and zinc. Traumacal (1.5 kcal/ml) had these same additions and was diluted with water to yield a final concentration of 1.0 kcal/ml. Thus, neither Osmolite nor Traumacal was truely fed to patients, as both were altered prior to feeding. Moreover, the Modular tube feeding (Shriner’s diet) group received a low-fat, low-calorie diet compared to the other groups, for whom caloric and fat intake was not restricted, Moreover, it was not easily ascertained from the text what the caloric contribution of oral versus tube feeding even was. As a result, while caloric and protein intake was similar among the three groups, intake of total fat and linoleic acid in particular was significantly lower in the Shriner’s modular diet-a difference that would indeed affect final outcome.2-4 BRADLEY C. BORLASE, M.D. STACEY J. BELL, M.S., R.D. GEORGE L. BLACKBURN, M.D., PH.D. New England Deaconess Hospital Boston, MA 02215
Response to Letter from Drs. Borlase, Blackburn, and Ms. Bell To the Editor: Thank you for the opportunity to respond to the letter from Drs. Borlase, Blackburn, and Ms. Bell. Their point is well taken that neither Osmolite nor Traumacal wars truly fed to patients, as both products were modulated (ie, enriched with protein and vitamins in the case of Osmolite; and Traumacal was diluted with water and fortified with vitamins). This was an intentional component of our study design since we felt that it was important to deliver to all three groups an isovolemic, isonitrogenous tube-feeding regimen containing 1 adequate micronutrient supplementation for burns.’ We were more interested in studying quantitative differences of nutrient intake rather than specific products. Furthermore, Dr. Borlase’s letter incorrectly states that the Traumacal group received a low-fat, low-calorie diet. On the contrary, the modular tube feeding group (group 2) was the only group restricted in fat and calories by mouth. This was done in an effort to ensure that total fat and linoleic acid intake would be lowest in group 2. Finally, we agree with Drs. Borlase, Blackburn, and Ms. Bell that incidence of smoke inhalation may be a confounding variable. As we concluded on page 234 of the original article, &dquo;It is likely that mortality data partially reflect complications resulting from concomitant pulmonary injury, although both death and smoke inhalation were not statistically different among the three groups.&dquo; We have addressed this concern in more detail
elsewhere.22
MICHELE GOTTSCHLICH, PH.D., R.D., C.N.S.D. GLENN D. WARDEN, M.D. Shriners Hospital for Crippled Children Burns Institute Cincinnati, OH 45219 REFERENCES 1. Gottschlich
MM, Jenkins M, Warden GD, et al: Differential effects of three enteral dietary regimens on selected outcome variables in burn patients. JPEN 14:225-236, 1990. 2. Gottschlich M, Warden GD, Carey M: Response to letter from Drs. Heimburger and Akrabawi. JPEN 14:666, 1990.
REFERENCES
The 1. Gottschlich
MM, Jenkins M, Warden GD, et al: Differential effects of three enteral dietary regimens on selected outcome variables in burn patients. JPEN 14:225-236, 1990 2. Bell SJ, Molnar JA, Carey M, Burke JF: Adequacy of a modular tube feeding diet for burned patients. J Am Dietet Assoc 86:13861391, 1986 3. Bell SJ, Blackburn GL: Nutritional support of the burned patients. In: Acute Management of the Burned Patient, Martyn JA (ed). W. B. Saunders Co, Philadelphia, 1990, Chap 10, pp 138-158 4. Wan JMF, Teo TC, Babayan VK, Blackburn GL: Invited comment:
Refeeding syndrome: A Review
To the Editor: The scholarly review by Drs. Solomon and Kirby addresses many important questions, and provides a clear
DOUGLAS C. HEIMBURGER, M.D. Associate Professor and Director Division of Clinical Nutrition Departments of Nutrition Sciences and Medicine University of Alabama Birmingham, AL 35294
SALIM S. AKRABAWI, PH.D., M.D. Director, Medical Services Mead Johnson Nutritional Group Evansville, Indiana 47721
Response to Letter from Drs. Heimburger and Akrabawi To the Editor: We read with interest the letter of Drs. Heimburger and Akrabawi. They have properly summarized our conclusion that the administration of a new modular tube feeding recipe designed to meet the unique nutritional needs of burn patients supported a better outcome in terms of wound infection and length of hospital stay. We maintain this viewpoint, but are not surprised that such findings would generate concern from the proprietors of Traumacal (Mead Johnson). In burn centers, the severity and predicted outcome from thermal injuries is typically estimated by the age and percent of the body surface area burned.’,’ For this reason, the aforementioned study utilized an experimental design in which diets were tested for efficacy by randomizing patients into three different feeding groups utilizing a random number table stratified for age, institution, and burn size. Patients with burns less than 40%, 40 to 60%, and above 60% were randomized independently into subsets in order to help insure comparability of burn size between the control and experimental groups. Subjects were also blocked into the following age categories: 3 through 11, ages greater than 11 and less than or equal to 21, ages greater than 21 and less than 40, ages greater than or equal to 40 and less than or equal to 65, and finally, greater than 65 years of age. Only patients able to take at least 75% of their targeted calories enterally during the first week after admission were included in the final analysis, because deficiencies caused by early caloric deprivation could have overshadowed any influence of difference in the three feeding
systems.
properly randomized clinical trials, such as the one described, the use of differences in relevant patient characteristics can be considerably reduced, but is not eliminated. For factors which can be measured, treatment group comparability can be tested by some objective criterion (a statistical test), and significant differences can be adjusted for in the analysis stage, sample size permitting. In this study, no significant differences were found between the treatment groups, so subgroup analysis was not undertaken. Additionally, while group 3 In
(Traumacal)
appears to have
a
greater share of smoke
inhalation among the measurable patient factors, there are innumerable clinical effects which theoretically could present unrecognized negative bias in the other two as well, such as alcoholism, drug abuse, preburn malnutrition, natural immunity, severity of inhalation injury, medical history, and associated trauma, to name
groups
a
few.
Certainly, the response to a burn is multifactorial. Outcome can be modified to a great degree by the presence or absence of other disease conditions or associated injuries. We elected not to exclude patients with inhalation injury because it is commonly present in this population and our objective was to determine an optimal diet therapy program for all burns. As we state on page 234 of the original article, &dquo;It is likely that the mortality data partially reflect complications resulting from concomitant pulmonary injury, although both death and smoke inhalation were not statistically different among the three groups.&dquo; Since there were no statistical differences found in smoke inhalation or any other patient factor studied, subgroup analysis or complicated regression techniques (multiple logistic model for qualitative outcomes as primarily measured here) were not undertaken. If significant differences had existed between the treatment groups, these technique(s) would have been appropriate. In summary, the concept of improving outcome by the use of a tube feeding recipe designed to meet the unique nutritional needs of burn patients portends an exciting future in terms of diet therapy. However, a major limitation of the aforementioned clinical trial, as with most studies involving human subjects include the inability to precisely control extraneous clinical effectors. Numerous events and intake variables indeed complicate the process.
MICHELE GOTTSCHLICH, PH.D., R.D., C.N.S.D. GLENN D. WARDEN, M.D. MARK CAREY, M.S. Shriners Burns Institute
Department of Surgery University Hospital Cincinnati, Ohio REFERENCES
I, Flora JD, Bawol R: Baseline results of therapy for burned patients. JAMA 236:1943-1947, 1976 Feller I, Jones CA: The National Burn Information Exchange. The use of a national burn registry to evaluate and address the burn problem. Surg Clin North Am 67:167-189, 1987
1. Feller 2.
Assessing Three Enteral Dietary Regimens for Burn Patients To the Editor: We read with great interest the paper by Gottschlich et al’ in which they describe the use of three enteral
667
dietary regimens for burn patients and assess outcome variables. From the data presented, clear differences in outcome
Lipids and the development of immune dysfunction- JPEN 12:435475, 19S8
existed among the three groups, with the diet
developed by Shriners Burns Institute staff being far superior to the others. Patients randomized to this diet had significantly fewer wound infections and shorter length of stay/percent burn. In addition, these patients had fewer pneumonias (p 0.06), fewer infectious episodes (p 0.07), and fewer deaths (p 0.06). However, we are concerned that although the data in Table III denote no significant differences between the patient groups (except in preburn weights), there may be important clinically relevant differences that did not achieve statistical significance. Specifically, twice as many patients in group 3 suffered smoke inhalation (n=8) than in the other groups (n=4); =
=
=
Table VIII indicates that 50% of deaths were attributed to smoke inhalation injury. Whereas only one of the two deaths in groups 2 (Shriner’s diet) was directly attributed to smoke inhalation, four of seven deaths in group 3 resulted from smoke inhalation injury. Thus it is difficult to conclude that the differences in outcome are due to diet alone; patient differences most likely played a role as well. Regarding the diets themselves, Table I lists the three diets as Osmolite-enriched with Promix; Modular tube feeding; and Traumacal. In reality, all three formulas are modular in nature, as each of the regimens were manipulated. In addition to Promix (whey protein), Osmolite had supplemental multivitamins and single doses of vitamins A, C, and zinc. Traumacal (1.5 kcal/ml) had these same additions and was diluted with water to yield a final concentration of 1.0 kcal/ml. Thus, neither Osmolite nor Traumacal was truely fed to patients, as both were altered prior to feeding. Moreover, the Modular tube feeding (Shriner’s diet) group received a low-fat, low-calorie diet compared to the other groups, for whom caloric and fat intake was not restricted, Moreover, it was not easily ascertained from the text what the caloric contribution of oral versus tube feeding even was. As a result, while caloric and protein intake was similar among the three groups, intake of total fat and linoleic acid in particular was significantly lower in the Shriner’s modular diet-a difference that would indeed affect final outcome.2-4 BRADLEY C. BORLASE, M.D. STACEY J. BELL, M.S., R.D. GEORGE L. BLACKBURN, M.D., PH.D. New England Deaconess Hospital Boston, MA 02215
Response to Letter from Drs. Borlase, Blackburn, and Ms. Bell To the Editor: Thank you for the opportunity to respond to the letter from Drs. Borlase, Blackburn, and Ms. Bell. Their point is well taken that neither Osmolite nor Traumacal wars truly fed to patients, as both products were modulated (ie, enriched with protein and vitamins in the case of Osmolite; and Traumacal was diluted with water and fortified with vitamins). This was an intentional component of our study design since we felt that it was important to deliver to all three groups an isovolemic, isonitrogenous tube-feeding regimen containing 1 adequate micronutrient supplementation for burns.’ We were more interested in studying quantitative differences of nutrient intake rather than specific products. Furthermore, Dr. Borlase’s letter incorrectly states that the Traumacal group received a low-fat, low-calorie diet. On the contrary, the modular tube feeding group (group 2) was the only group restricted in fat and calories by mouth. This was done in an effort to ensure that total fat and linoleic acid intake would be lowest in group 2. Finally, we agree with Drs. Borlase, Blackburn, and Ms. Bell that incidence of smoke inhalation may be a confounding variable. As we concluded on page 234 of the original article, &dquo;It is likely that mortality data partially reflect complications resulting from concomitant pulmonary injury, although both death and smoke inhalation were not statistically different among the three groups.&dquo; We have addressed this concern in more detail
elsewhere.22
MICHELE GOTTSCHLICH, PH.D., R.D., C.N.S.D. GLENN D. WARDEN, M.D. Shriners Hospital for Crippled Children Burns Institute Cincinnati, OH 45219 REFERENCES 1. Gottschlich
MM, Jenkins M, Warden GD, et al: Differential effects of three enteral dietary regimens on selected outcome variables in burn patients. JPEN 14:225-236, 1990. 2. Gottschlich M, Warden GD, Carey M: Response to letter from Drs. Heimburger and Akrabawi. JPEN 14:666, 1990.
REFERENCES
The 1. Gottschlich
MM, Jenkins M, Warden GD, et al: Differential effects of three enteral dietary regimens on selected outcome variables in burn patients. JPEN 14:225-236, 1990 2. Bell SJ, Molnar JA, Carey M, Burke JF: Adequacy of a modular tube feeding diet for burned patients. J Am Dietet Assoc 86:13861391, 1986 3. Bell SJ, Blackburn GL: Nutritional support of the burned patients. In: Acute Management of the Burned Patient, Martyn JA (ed). W. B. Saunders Co, Philadelphia, 1990, Chap 10, pp 138-158 4. Wan JMF, Teo TC, Babayan VK, Blackburn GL: Invited comment:
Refeeding syndrome: A Review
To the Editor: The scholarly review by Drs. Solomon and Kirby addresses many important questions, and provides a clear
