Centre for Burns and Plastic Surgery, Pirogov Medical Institute, Bulgaria

SUMMARY. An analysis was made of the causes of death in 610 burn patients over the age of 60 yr treated at the Centre for Burns and Plastic Surgery, Pirogov Medical Institute, Sofia, Bulgaria, over a period of 11 years (1980-90). Of these patients, 144 died. Attention is directed mainly at septic complications, which were lethal in 38 patients (57.6%). The conclusions drawn could serve as a starting-point for correcting treatment methods in elderly burn patients in order to improve cure protocols and achieve better recovery.

Problems related to the birth-rate in Bulgaria have led to premises for health care considerations regarding patients over the age of 60 yr. Although not a topical problem at the present time, in the future the treatment of elderly burn patients will undoubtedly serve as a startingpoint for future research work on the subject.`

Retrospective and prospective studies were carried out in relation to the 3769 burned patients treated in our unit (Centre for Burns and Plastic Surgery, Pirogov Medical Institute, Sofia, Bulgaria) over a period of eleven years. Of these patients, 610 (16.2%) were aged over 60 years.
The factors determining the severity of the burn injury were studied. The indices characterizing burn trauma and having an impact on its outcome were studied in their dynamics (on post-burn days 1, 2, 3, 5, 7, 28 and 35). The data were treated statistically using W. J. Dixon's Biomedical Computer Programs '90 of the University of California.

Out of the 610 patients we treated who were aged over 60 years, with burn injuries of varying degree, 144 (23.60%) died. Their ages ranged between 60 and 101 years (mean, 83 ± 13). The total burned area ranged from 1 to 54% (mean, 40 ± 18%) and Ill-degree full-thickness skin burn from 1 to 40% (mean, 22 ± 12%.
Data analysis justified division of the deceased patients into three groups:

• Group 1: deceased as a result of the burn trauma -20 patients (13.9%)
• Group 2: victims of myocardial infarction and lung embolism - 41 patients (28.5%)
• Group 3: victims of infectious complications (pneumonia, bacteraemia and sepsis) - 83 patients (57.6% )

During the first 72 h post-trauma, shock and severe upper airway burns caused the death of ten men (6.9%) and ten women (6.9%). By days 5-7 another 30 men (20.8%) and 11 women (7.6%) had died of lung embolism (60%), arrhythmia (32%), and myocardial infarction (8%).
The following conclusions can be drawn on the basis of existing data:

• burn trauma is lethal in its most severe form (p < 0.001)
• females and males are victims in equal numbers
• cardiovascular complications (embolism, myocardial infarction, and arrythmia) appear during the first days following thermal shock. The reasons for heart failure are severe electrolytic imbalance and improper use of diuretics

As far as diagnostics is concerned, cases from the third group that developed infectious and bacteriological complications (pneumonia, general bacteraemia, and sepsis) were the most important. Numerous authors have studied these causes simultaneously as the main causes of mortality in burn patients.
Differentiation between septic infections is in fact not clear and it is almost impossible to determine when one infection is growing into another.'-"' In spite of the virulence of the proliferating agent, the condition of the patient's immune system and antibiotic and surgical treatment play a significant part.
We consider our interest in the group of elderly patients justified because in most cases infectious complications appear late, even after the first or second skin grafting. Fig. I shows that the highest number of lethal cases occurred around days 5 and 28.

Table I presents the main characteristics of patients with thermal trauma and its severity according to indices of body surface area (BSA), area of full-thickness skin burn, and localization .2 In order to obtain a clearer view of statistical data we include eleven patients who survived (Group 1) after an infectious complication.

It should be noted that in Group 2 (deceased patients) trauma was more severe in more advanced age. We observed a statistically significant difference as regards these two indices (p < 0.01). It should also be noted that females survived thermal shock more frequently than males, probably because of their stronger immune condition. Consequently, given equal conditions and burn severity, the trauma exerts more influence on the course of the disease and lethality in men than in women
Pneumonia and other septic infections remain the prerogative of women in the later stages of the disease (p < 0.001). Fig. 2 represents the time of appearance of bacterial infection, pneumonia, and syndromes of acute organ failure.

The consequent bacterial infection, pneumonia, and acute respiratory and then kidney failure are evident, thus constituting the multiple organ failure syndrome.' Fig. 2 also shows that the relative part of pneumonia cases started to increase after day 14 day following the trauma, reaching its maximum in about the fourth week. A strong correlative dependence (r > 0.9) exists, in our opinion, between the slightest burns and pneumonia lethality, if it was the only cause of death. The only logical reason is that the patients are bedridden and the coughing reflex is inhibited. With increased trauma severity, it is more common to find mixed forms of bacterial-infectious complication (sepsis <-> pneumonia). When BSA was 10 ± 5% and the full-thickness skin burn 5 ± 2% BSA, we observed 50% lethality. On admission, these patients had an APACHE 11 score of 15-20 points.
With larger burns (20 ± 2%), sepsis was the leading cause of mortality more often, with multiple organ failure developing with varying rapidity. The speed of development of the multiple organ failure syndrome is not substantial, because with very few exceptions the process is irreversible: the patients are bound to die.' The commonest causes are Staphylococcus aureus, Streptococcus epidermidis and Pseudomonas aeruginosa, the most severe undoubtedly being Pseudomonas sepsis, with 100% mortality.
In the third group of elderly patients with infectious complications the lethality rate was 88%. In conclusion, we point out that the severity of the trauma mostly concerned male patients and undoubtedly depended on the course of the disease (p < 0.01).
The appearance of infectious complications in elderly burned patients has its peculiarities:

• women suffer more often from such complications (P < 0.01)
• in cases of less severe burns, pneumonia prevails as the lethal cause; the relative part of pneumonia increases after day 14, reaching its maximum on about day 28 50% of lethality is observed with BSA = 10 ± 5%
• and 5 ± 2%, when full-thickness skin burns are Illdegree the presence of infectious complications leads to a mortality rate of 88%

RESUME. Les Auteurs ont effectué une analyse des causes de la mort de 610 patients brûlés âgés plus de 60 ans traités au Centre de Brûlures et de Chirurgie Plastique, Institut Médical Pirogov, Sofia, Bulgarie, pendant une période de Il ans (1980-90). De ces patients, 144 sont morts. L'attention majeure se concentre sur les complications septiques, qui étaient mortales dans 28 patients (57,6%). Selon les Auteurs, les conclusions que l'on peut tirer pourraient servir comme point de départ pour corriger les méthodes de traitement chez les patients brûlés âgés pour améliorer les protocoles de traitement et obtenir une guérison meilleure.

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