Annals of Burns and Fire Disasters - vol. XIII - n. 2 - June 2000

TREATMENT AND MORTALITY TRENDS AMONG MASSIVELY
BURNED PATIENTS

O'Mara M.S., Caushaj P., Goldfarb I.W., Slater H.

Department of Surgery, Burn Trauma Unit, The Western Pennsylvania Health System, Pittsburgh, Pennsylvania, USA

RESUME. Despite advances in burn care techniques, there remains a trend towards therapeutic failure in patients who sustain burns in more than 60% total body surface area (TBSA). Predictors of survival that have been seen include age, burn size, amount of full-thickness burn, inhalation injury, mechanism of burn, timing and appropriateness of resuscitation, and concurrent complications. We reviewed the data of patients with 60% or greater TBSA burns seen at our Burn Trauma Unit over the past five years. The purpose of this was to evaluate our practices as well as the success of current therapy. During the time period reviewed 39 patients were admitted with this significant level of injury. They were all treated with appropriate resuscitation and early excision and grafting. All available demographic, historical, therapeutic, and outcome data were gathered. Statistical analysis was undertaken to identify variables, which presented significant differences between the group of survivors and that of patients who died. Of the 39, 28 patients succumbed. Larger burns, more full-thickness burns, inhalation injury, the need of escharotomy, and anuria/oliguria were all associated with a decreasing chance of survival. Delay in arrival at the burn trauma unit was also associated with poor outcome, as was earlier first operative excision. Greater burns severity led to basic malfunctioning of the physiological response, as seen in the inadequate effect of resuscitation: essentially, the more extensive the burn the higher the likelihood of mortality. The key to improving our ability to treat massively burned patients seems to lie in be;ter and prompter resuscitation, better treatment of pulmonary injury, and better understanding of how to halt the underlying deteriorating physiological process in more severe burns.

Despite advances in burn care techniques, there remains a trend towards therapeutic failure in patients who sustain burns in more than 60% total body surface area (TBSA). Predictors of survival that have been seen include age, burn size, amount of full-thickness burn, inhalation injury, mechanism of burn, timing and appropriateness of resuscitation, and concurrent complications. We reviewed the data of patients with 60% or greater TBSA burns seen at our Burn Trauma Unit over the past five years. The purpose of this was to evaluate our practices as well as the success of current therapy. During the time period reviewed 39 patients were admitted with this significant level of injury. They were all treated with appropriate resuscitation and early excision and grafting. All available demographic, historical, therapeutic, and outcome data were gathered. Statistical analysis was undertaken to identify variables, which presented significant differences between the group of survivors and that of patients who died. Of the 39, 28 patients succumbed. Larger burns, more full-thickness burns, inhalation injury, the need of escharotomy, and anuria/oliguria were all associated with a decreasing chance of survival. Delay in arrival at the burn trauma unit was also associated with poor outcome, as was earlier first operative excision. Greater burns severity led to basic malfunctioning of the physiological response, as seen in the inadequate effect of resuscitation: essentially, the more extensive the burn the higher the likelihood of mortality. The key to improving our ability to treat massively burned patients seems to lie in be;ter and prompter resuscitation, better treatment of pulmonary injury, and better understanding of how to halt the underlying deteriorating physiological process in more severe burns.

Methods

The data of all patients treated in our burn trauma unit over a five-year period were reviewed. Only patients of at least 18 years of age were included. All demographic, historical, therapeutic, and outcome data were considered. Patient data were subsequently analysed for age, TBSA burn, area of full-thickness burn, presence of inhalation injury, and the need of escharotomy. Also evaluated were the quantities of initial 24 h urine output, the presence of anuria or oliguria, and the duration of transport to the burn trauma unit. Surgical procedures were quantified as to number and the timing of the first excision and grafting.
All patients with massive burns were treated with plasma or crystalloid resuscitation, while patients with smaller burns or without full-thickness burns received crystalloid resuscitation. Resuscitation efforts were modified on the basis of patient response in order to maintain adequate urine output. The diagnosis of inhalation injury was made on clinical grounds based on the injury mechanism, the presence of carbonaceous sputum, and singeing of the nares. If pulmonary injury was suspected but could not be objectively evaluated, bronchoscopy was performed for diagnosis. Early excision and grafting were undertaken within the first seven days of hospitalization, according to the attending surgeon's evaluation of the patient's clinical readiness. Dressing changes were done with topical silver sulphadiazine for general care and mafenide acetate to the ears. Patient data were gathered on an hourly basis.
Statistical analysis of the data was done using chisquare and t-test as appropriate to compare the data of survivors with those of mortalities, and early mortalities with later mortalities (i.e. after the initial 24 h period).

Results

During the period under review, 39 patients with burns in 60% or greater TI3SA were admitted (Table I). Of these, 11 survived and 28 died, 10 within the first 24 h after being burned and 18 subsequently. Demographic data revealed that the survivors consisted of nine males and two females with a mean age of 45.9 yr (range, 18 to 86 yr). Mortalities consisted of 23 men and five women, mean age 52.0 yr (range, 20 to 83 yr). Early mortalities and late mortalities were similarly divided. There were no significant differences with regard to sex or age in any group of patients surviving or dying.

Burn severity was less in survivors, as manifest in TBSA (67.2% versus 80.2% in mortalities) and fullthickness burns (19.4% versus 72.3% in mortalities) (Table II).

Inhalation injury was more frequent in mortalities (92.9% versus 18.2% in survivors (Table III), and patients dying were more likely to require escharotomies (60.7% versus 18.2% in survivors) (TableIV).

Oliguria and anuria, taken together, were more common in mortalities (75.0% versus 36.4% in survivors), anuria being defined as no urine output for a given 8 hr period and oliguria as less than 0.5 cc/kg/h urine output for 8 h (Table V). Survivors also appeared to gain less weight (11.3% of admission weight) than non-surviving patients who lived beyond the first 24 h (20.8% gain) (Table V).

A comparison between the groups of patients who died early and those whose mortality was delayed indicated a cut-off before and after the first 24 h post-burn. Late mortalities had smaller burns and fewer full-thickness burns compared with early mortalities (T13SA 74.4% versus 90.6%, p < 0.00 1; full-thickness burns 64.5% versus 86.4%, p < 0.01) (Table 11). There was no difference in the incidence of inhalation injury among mortalities (Table III). The two groups presented a similar need for escharotomy (Table IV). Resuscitation outcomes were also similar in the two groups
(Table V). Survivors and patients who died late underwent a similar number of procedures (2.9 versus 3.2 in mortalities)

(Table VI), but survivors showed a greater delay before the first procedure (4.1 days versus 1.8 in mortalities) (Table VI).

Mortalities surviving beyond the first 24 h had experienced a delay in arrival at the burn trauma unit. Late deaths had a 3.93 h delay before reaching the unit, survivors 2.54 h, and early mortalities 2.45 h (Table VII).

A comparison of patients who were taken for their first excision early (within the first 3 days) with patients who were taken later shows a clear difference in full-thickness burns (46.4% versus 26% for later excision), inhalation injury (71.4% versus 0% for later excision), and incidence of death (64.3% versus 16.7% in later excision) (Table VIII). These two groups, i.e. early and later excision, presented similar TWA, age, and number of procedures.

Discussion

The poor outcome of patients sustaining massive burns remains an ever-present problem in burn care. The 72% mortality rate among patients in our burn trauma unit bears witness to this fact. Although this is a higher mortality rate than that seen in many other studies, it is only slightly higher, with others reporting rates in the 50-65% range in this extent of burns. This higher incidence of burns may stem from the non-selectivity of admission to our burn trauma unit, which takes all burn patients in all states of injury, and also from the long distances many of our patients need to be transported before adequate resuscitation can be instituted.For the most part, the demographic factors we examined reflect known areas of mortality risk that have already been delineated. Specifically, burns of larger area and greater full thickness lead to an increased numbers of deaths. Inhalation injury remains a continued confounding factor that aggravates the outcome. Interestingly, in our patients we saw no difference as regards survivors and mortalities. Resuscitation parameters were used both to measure the patients progress and as a predictor of outcome. Although the differences were not significant, the patients who died from their burns had a lower urine output in the initial 24 h as well as a larger weight gain during the course of resuscitation. Both these parameters have been shown to be indicators of poorer outcome, The effect of fluid retention was probably mitigated in our patients owing to our wide use of plasma resuscitation." Plasma has been shown to decrease fluid retention, and it might thus improve outcome.In the past, early death has meant patients dying within the first seven days post-burn. In our review we noted a distinctive cut-off after the first 24 h. Either patients died before or at 24 h or we were able to sustain them up to 72 h and beyond. Early mortalities (patients dying during the initial 24 h post-burn) presented more serious burns, i.e., larger TBSA and more full-thickness burns. The differences did not go beyond that, as inhalation injury incidence and resuscitation values were similar in the two groups.It is known that delay in the initiation of resuscitation will lead to the rapid demise of burn patients. There was a trend among our patients for one particular group to take longer to anive at the burn trauma unit. This group consisted of patients who died after the initial 24 h postburn, i.e. late mortalities. Although the time difference was only about one and a half hours, it was associated with a higher incidence of delayed death.Recent trends favour earlier and more aggressive operative intervention, and early excision is defined as that performed done within the first 7 days post-burn.Among our patients, those who died had been taken to the operating room earlier, by an average of more than two days (1.8 versus 4.1 days in survivors). The timing of burn excision is a subjective decision taken by the attending surgeon, and it is difficult to make a direct association between death and earlier excision. It is clearly possible that patients who appeared to be in worse condition (and who actually were burned more severely) were taken for grafting earlier as they were considered to need it more, while stable patients were left to wait until their burns manifested their depth. In order to evaluate this trend we reviewed patients taken for the first procedure in the first three days compared with those taken later. It was found that patients taken earlier did in fact have greater percentages of full-thickness burns, which would have manifested themselves earlier as needing excision. These early patients also had a higher incidence of inhalation injury, and thus would have appeared to be more seriously ill. Death was also more likely in the group operated upon earlier. We cannot determine if this early intervention was detrimental or helpful to these patients.The traditional causes of mortality in burn patients still exist. There is a basic malfunctioning of the physiological response related to burn severity and concomitant injury that we must learn to correct and treat. It will continue to be true that the worse the burn the poorer the resuscitation, and the more likely the patient is to succumb. We must therefore continue to focus our efforts on rapid, efficient resuscitation, on better treatment of pulmonary injury, and on research on how to halt the physiological disturbances that characterize our patients.

RESUME. Malgré les progrés dans les techniques des soins des brùlés, nous continuons à assister à des insuccés thérapeutiques dans les patients atteints de brùlures dans £ 60% de la surface corporelle totale. Les facteurs sur la base desquels on peut prédire la survie incluent I'âge, 1'extension des brùlures, la proportion des brfflures A toute épaisseur, les lésions dues à l'inhalation, le mècanistne de la brfilure, les temps et la propriété de la réanimation, et les complications concomitantes. Les Auteurs ont éxaminè les donnèes des patients atteints de brùlures dans £ 60% de la surface corporelle totale traités dans notre Unité des Brùlures pendant les cinq années passées. Le but de notre recherche était d'ùvaluer nos méthodes et le succés de la thérapie actuelle. Pendant cette période 39 patients ont été hospitalisés avec ce niveau significatif de lésion. Tons les patients ont été traités avec la réanimation appropriée et 1'excision et la greffe précoce. Toutes les informations disponibles de nature démographique, anamnestique, thérapeutique et qui concemaient le résultat final ont été réunies. Les àuteurs ont effectué une analyse statistique pour identifier les variables, qui étaient significativement différentes entre le groupe des patients qui ont survécu et ceux qui sont morts. De nos 39 patients 28 sont morts. La possibilité de la survécue diminuait dans les brùlures plus étendues et celles qui présentaient 1'extension majeure des brùlures à toute épaisseure, les lésions dues à l'inhalation, la nécessité de Fescharotomie et I'anurie/oligurie. àussi le retard dans l'hospitalisation était associè aux. r6sultats inadéquats, comme aussi la premi6re excision opdratoire plus prècoce. La retard majeure des brùlures provoque un malfonctionnement fondamental de la réponse physiologique, ce qui est dèmontré par l'effet insuffisant de la réanimation. Essentiellement, la probabilité de la mortalité s'augmente selon 1'extension des lésions. La clef pour améliorer notre capacité de traiter les grands bralés semble dépendre d'une réanimation meilleure et plus rapide, d'un traitement meilleur des lésions pulmonaires, et de la compréhension plus compléte des méthodes pour fertner le processus sous-jacent qui se déteriore dans les brùlures plus sévéres.

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