Bonny H. Wallace

The tumescent technique to significantly reduce blood loss during burn surgery

INTRODUCTION Burn surgery is complicated by blood loss. The tumescent technique of subdermal injection of epinephrine has been utilized to decrease intraoperative blood loss. We hypothesized that this would safely decrease blood loss during burn surgery. METHODS Twenty patients utilized the tumescent technique. The tumescent group had subdermal injections of epinephrine beneath the excision and donor site plus thrombin spray and warm saline soaked laparotomy pads. Ten patients grafted prior to adopting the tumescent technique utilized thrombin spray and warm saline soaked laparotomy pads for hemostasis. Blood loss was determined by operative estimation and calculation. Data were analyzed by Students t-test and paired t-test. RESULTS The two groups were demographically similar. The tumescent group had significantly less total blood loss and blood loss per unit area excised. There were no clinically detectable arrythmias, changes in heart rate or blood pressure noted. CONCLUSIONS The tumescent technique significantly reduced intraoperative blood loss. It is safe, inexpensive and easy to use. The subdermal epinephrine/saline injection creates a smooth, tense surface which assists with debridement and donor harvest.

Humoral versus neural pathways for fever production in rats after administration of lipopolysaccharide.

BACKGROUND These studies address the question of the relative roles of humoral and neural pathways in the genesis and control of the fever component of the acute phase response. METHODS Two experiments were performed to examine the effect of vagotomy (VagX) on the febrile response to intraperitoneal (i.p.) and intra-arterial (i.a.) lipopolysaccharide (LPS), and plasma cytokine and LPS concentrations after intravenous (i.v.) or i.p. injections of LPS. In experiment 1, body temperature (T(B)) was obtained from unperturbed animals by using radio transmitters and telemetry after injection of LPS i.a. or i.p. In the second study, serial blood samples were obtained for cytokine and LPS assay after injection of LPS either i.v. or i.p. Colonic temperatures (T(C)) were obtained from indwelling thermistors. RESULTS The maximal increments in T(B) for animals receiving LPS i.a. and i.p. with or without VagX were not different from one another: sham vagotomy (Sham-VagX) + LPS i.a., 1.20 +/- 0.26 degrees C; VagX + LPS i.a., 1.23 +/- 0.64 degrees C; Sham-VagX + LPS i.p., 1.45 +/- 0.27 degrees C; VagX + LPS i.p., 1.50 +/- 0.35 degrees C (F = 1.12, p = 0.36). Neither were the four resulting response curves for T(B) different from one another. Plasma levels of LPS, tumor necrosis factor-alpha, and interleukin-6 were significantly elevated at 45 minutes after LPS injection by either the i.v. or i.p. routes, preceding any increments in T(B), and were not effected by VagX. CONCLUSION Fever development for animals receiving LPS in experiment 1 demonstrates a temporal relationship -- with increments in plasma levels of LPS and pyrogenic cytokines obtained in experiment 2 after administration of LPS either i.p. or i.v. Vagotomy had no discernible effect on the responses regardless of the route of administration of LPS.

The interrelationships between wound management, thermal stress, energy metabolism, and temperature profiles of patients with burns

This prospective randomized study was performed to evaluate the metabolic and thermal responsiveness of patients with burns to thermal stress with three protocols of wound care: group I (n = 7) treated with dressings and variable ambient temperature selected for patients subjective comfort; group II (n = 7) treated without dressings and variable ambient temperature for patient comfort; group III (n = 6) treated without dressings and ambient temperature of 25 degrees C, electromagnetic heaters were set to achieve patient subjective comfort; and group IV (n = 6) healthy volunteers. After baseline partitional calorimetry was performed, individual patients were cold-challenged while subjectively comfortable by sequentially lowering either the ambient temperature or the output from the electromagnetic heaters. Heat balance and temperatures were obtained after each perturbation in external energy support. For patients in groups I and II, subjective perception of thermal comfort (warm, neutral, neutral and fed, cool, or cold) was more strongly correlated (p < 0.02) with the changes in the rate of heat production than the actual ambient temperature. For patients treated with electromagnetic heaters, changes in heat production were most strongly correlated with the energy output from the electromagnetic heaters. Even though the environmental conditions required to achieve a particular level of comfort are quite different between treatment groups, the difference in temperature between the patients surface and ambient is approximately the same for groups I, II, and IV for each subjective state.(ABSTRACT TRUNCATED AT 250 WORDS)

Ibuprofen lowers body temperature and metabolic rate of humans with burn injury.

A group of 15 burned children and young adults with large burns (mean, 41% +/- 15% BSA) were administered ibuprofen (40 mg/kg for 3 days). Each patient served as his or her own control in this crossover study (with and without ibuprofen). Paired calorimetric and temperature studies and urinary nitrogen measurements were performed. No nitrogen-sparing effect was identified for this dose of ibuprofen. However, patients demonstrated a statistically significant reduction in average rectal temperature (0.67 degrees C decreases) (p less than 0.01) and in metabolic rate (11.4% decreases) (p less than 0.01) while taking ibuprofen. Linear regression analysis of the reduction in temperature versus the reduction in metabolic rate yielded a statistically significant correlation (p less than 0.01) with a slope of 13.6% reduction in metabolic rate per degree centigrade reduction in the 72-hour average rectal temperature. These results support the hypothesis that ibuprofen attenuates the hypermetabolic response to thermal injury by blunting the temperature elevation that is usually seen.

Manipulation of the inflammatory response to burn injury

BACKGROUND Burn injury is characterized by hypermetabolism and protein catabolism. Endotoxin, derived from either wound or gut, may participate in this response. METHODS Eleven seriously burned patients were treated with the endotoxin-binding agent polymyxin B and underwent partitional calorimetry and nitrogen balance studies. The data from theses patients were compared with data from 28 contemporary, similarly burned patients who did not receive polymyxin B. RESULTS Elevated levels of circulating endotoxin were not consistently detected in either group. Interleukin-6 was elevated and correlated with rectal temperature and nitrogen excretion in both groups. Administration of polymyxin B produced no change in metabolic rate but produced a significantly more positive nitrogen balance and was associated with a prompt reduction in interleukin-6 levels. CONCLUSIONS These data support the hypothesis that endotoxin plays a role in the postburn protein catabolism but not in the hypermetabolic response. This protein catabolic response is statistically associated with circulating interleukin-6 levels, suggesting a possible role for interleukin-6 in postinjury protein wasting.

Pathogenesis of fever in a rat burn model : The role of cytokines and lipopolysaccharide

We investigated the possible causal relationship between interleukin-6 (IL-6) and increased body temperature (T(B)) in a rat burn model. Transmitters for measuring core temperature and estimating activity were implanted in the abdominal cavity. Animals in the burn group were clipped and received full-thickness scald burns to 45% to 55% of the body surface area, and control animals were clipped. T(B) and activity were measured continuously through the tenth postburn day. Carotid lines were placed, and serial blood samples obtained for lipopolysaccharide, IL-6, and tumor necrosis factor-alpha assay. From the third through the tenth postburn day, the burn group had a consistently significantly higher T(B) during light hours than the control group did (average, 0.45 degrees C +/- 10 degrees C, p = 0.0001). Differences in activity during light hours were not significant between the two groups, therefore, do not account for the observed significant difference in T(B). The average IL-6 serum levels were 3.5-fold higher for the burned animals. In this study, burn and control serum levels of IL-6 demonstrated positive correlation with T(B). These data suggest, but do not prove, a causal relationship between IL-6 and fever in the rat burn model, and make it unlikely that circulating systemic lipopolysaccharide is the cause.We investigated the possible causal relationship between interleukin-6 (IL-6) and increased body temperature (T(B)) in a rat burn model. Transmitters for measuring core temperature and estimating activity were implanted in the abdominal cavity. Animals in the burn group were clipped and received full-thickness scald burns to 45% to 55% of the body surface area, and control animals were clipped. T(B) and activity were measured continuously through the tenth postburn day. Carotid lines were placed, and serial blood samples obtained for lipopolysaccharide, IL-6, and tumor necrosis factor-alpha assay. From the third through the tenth postburn day, the burn group had a consistently significantly higher T(B) during light hours than the control group did (average, 0.45 degrees C +/- 10 degrees C, p = 0.0001). Differences in activity during light hours were not significant between the two groups, therefore, do not account for the observed significant difference in T(B). The average IL-6 serum levels were 3.5-fold higher for the burned animals. In this study, burn and control serum levels of IL-6 demonstrated positive correlation with T(B). These data suggest, but do not prove, a causal relationship between IL-6 and fever in the rat burn model, and make it unlikely that circulating systemic lipopolysaccharide is the cause.

Retrospective evaluation of admission criteria for paediatric electrical injuries

In the medical community, the practice of admitting all electrical burns for 24-48 h of observation, monitoring and laboratory evaluation is widespread. This retrospective review of paediatric electrical burns was conducted to determine which patients may safely be treated as outpatients. Retrospective analysis of all paediatric burns admitted between 1980 and 1991 identified 35 patients with electrical injuries. Patients were divided into two groups for analysis: those burned by exposure to household voltages (120-240 V; n = 26) and those exposed to high voltages, in excess of 1000 V (n = 9). The majority of household electrical injuries occurred secondary to contact with the household 120 V (21/26). Contact with an extremity accounted for the largest number of these injuries (18/26). The mouth was the second most frequent site of injury (7/26). Most of these patients (20/26) had < 1 per cent BSA burn. No patient in the household-voltage group had an arrythmia that required treatment, nor were there any identified examples of compartment syndrome or other vascular complications. Seven patients did require minimal skin grafting. No deaths occurred in either group. The patients in the household-voltage group were significantly younger. High-voltage electrical injuries occurred in an older patient population and required more aggressive care and surgical intervention. This was evident at the time of initial evaluation. Based on these data, healthy children with small partial-thickness electrical burns and no initial evidence of cardiac or neurovascular injury do not appear to need hospital admission.

Studies on the mechanism of fever after intravenous administration of endotoxin

BACKGROUND The sequential events in fever production after intravenous administration of lipopolysaccharide (LPS) remain unsettled and controversial. Vessels of the organum vasculosum laminae terminalis (OVLT) lack the tight junctions of the blood-brain barrier and allow substances of high molecular weight to enter the interstitium but not the neuropil. The present studies investigate the hypothesis that the OVLT is needed for fever production after intravenous administration of LPS in the rat. METHODS Electrolytic lesions were produced in the OVLT of rats. After recovery, left carotid and right atrial catheters were inserted, and 24 hours later calorimetry was performed. Blood was drawn for baseline assay for cytokines and LPS after which LPS was given intravenously, with studies continued for 5 hours, and additional blood samples were drawn at 90 and 300 minutes. RESULTS The maximal increment in rectal temperature for the sham lesion LPS group (1.25 +/- 0.44 degrees C) was significantly greater than for the sham-saline (-0.05 +/- 0.46 degrees C) and the lesion-LPS groups (0.35 +/- 0.45 degrees C) for minutes 120 to 300. Ninety minutes after LPS administration, serum levels of interleukin (IL)-6, tumor necrosis factor-alpha, and LPS were significantly elevated (p < 0.0001) above baseline for the sham-LPS and lesion-LPS groups. IL-1beta serum levels remained below detection levels. CONCLUSION Large lesions of the OVLT prevent and/or attenuate fever due to LPS even though tumor necrosis factor-alpha and IL-6 are greatly increased in serum. IL-1beta does not seem to be an endogenous humoral mediator in this model.

Sequential excision and grafting of the burn injuries of 1507 patients treated between 1967 and 1986: end results and the determinants of death.

The development of a more aggressive approach to burn wound management, leading to complete excision within 72 hours after burn, has led some to conclude that total early excision is a major force behind improved survival rates. We have summarized the results of treatment of 1507 patients with burn injuries treated between 1967 and 1986. Wounds were managed with use of standard topical therapy, occlusive dressings, and staged excision and grafting of full-thickness injury or deep dermal injury (not healed by 21 days). Data were analyzed with use of a logistic-regression model because, with the exception of older patient cohorts, the data did not fit the probit model. The major determinants predicting death were the percentage of body surface area burned, age, smoke inhalation, and the percentage of full-thickness burn. Concordance was 97%. These data show that aggressive sequential wound excision and grafting produces end results comparable with those achieved with complete early burn wound excision for similar age ranges and injury. Early harvest of available donor sites in patients with large burns may be more important to survival than complete early wound excision.

Severe acidosis alone does not predict mortality in the trauma patient

BACKGROUND Because severe acidosis is an indicator of poor prognosis in trauma patients, medical records of these patients were analyzed to determine whether aggressive resuscitation was appropriate. PATIENTS AND METHODS Data from a level 1 trauma center registry were reviewed retrospectively to identify patients with a pH < or = 7.0. Thirty-seven patients were identified. Severely acidotic patients were compared to average trauma patients in terms of demographics, resuscitation, injury, and outcome. Surviving acidotic patients were also compared to nonsurviving acidotic patients. RESULTS Half of the severely acidotic group survived initial resuscitation with approximately one third surviving to leave the hospital. There were no chronically disabled survivors. Nonsurviving acidotic patients were more unstable, more neurologically depressed, and more severely injured. Resuscitation efforts did not consume excessive hospital resources. CONCLUSION Severe acidosis alone is not a sufficiently powerful predictor of outcome to justify withholding resuscitation; however, when combined with coma and shock, this condition had no survivors in this small series.