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Burn patients in an early cohort (n=173) treated in an intensive care ward without separate enclosures were compared with a later cohort (n=213) treated in a renovated unit with separate bed enclosures. The number of patients developing infection was significantly reduced in the late group. Observed mortality was compared with mortality predicted on the basis of burn size and age alone. Reduction in observed compared with predicted mortality, inapparent in the early group, was seen in the late group and was restricted to the subgroup of patients with predicted mortality of 25% to 75%, in which the observed mortality of 28.3% was less than the predicted mortality of 48.7%. The incidence of infected patients was reduced from 58.1% in the early cohort to 30. 4% in the late cohort. In comparison of the early cohort with the late cohort, the overall proportion of patients with bacteremia was reduced from 20.1% to 9. 4%, while the incidences of both pneumonia and burn wound invasion remained unchanged. Providencia and Pseudomonas species, endemic in the early cohort, were eliminated in the late cohort. Reduction of infection by environmental manipulation in burn patients was possible and was associated with improved survival., Presented at the Annual Meeting of the Surgical Infection Society (5th) Held at New Orleans, LA. on 29 Apr 85.

In humans, a reduction in the circulating concentrations of bioactive thyroid hormones is characteristic of nonthyroidal illness (NTI). In burned patients, similar to patients with other NTI, serum concentrations of 3,5,3' - triiodothyronine (T3) and often tetraiodothyronine (T4), as well as the indices of free hormonal concentrations, FT3I and often FT4I (index = total hormone concentrations, FT3I and often FT4I(index = total hormone concentration times T3 uptake), are suppressed. To investigate the significance of such changes, we have characterized serum T4 and T3 after full-thickness scald burns (60% body surface under anesthesia) of 270-gm male Sprague-Dawley rats housed in a light:dark cycle of 14:10 hr. Because of failure of the in vitro charcoal T3 uptake to account for this serum bindng abnormality, the results are most consistent with a burn-induced circulating inhibitor(s) for binding of T4 and T3, not only to transport proteins but also in vitro charcoal, perhaps similar to inhibitors previously described in the sera of patients with various nonthyroidal illnesses. The thermally traumatized rat appears to be a good model for thyroid changes in burns and other nonthyroidal illness.

The Syrian (golden) hamster has provided the most extensively studied model of pineal physiology, and in the species the pineal gland has a potent suppressive effect on the reproductive system and on serum free thyroxim (T4) concentration. The pineal's suppressive effect on the gonads and T4 is classically evoked by subjecting the hamsters to a short photoperiod (less than 12-h light/day) or to blinding by bilateral orbital enucleation. Additional pinealectomy prevents the regression of the reproductive system and the reduction of T4. Burn injury of humans results in depressed serum concentrations of free triiodothyroxine (T3) and T4, reduced serum binding of T4, and low testosterone concentrations. Burned male Syrian hamsters (burn size 23% of body surface) exhibited reduced total (T4) and free (FT4) serum concentrations, a defect in T4 binding to serum proteins manifested by the T4 dialyzable fraction but not the in vitro T3 charcoal uptake, and reduced serum testosterone concentration. These changes are similar to those noted previously in burned humans. Unlike such patients, burned hamsters did not exhibit reduced serum T3 nor elevated rT3 concentrations in a reproducible manner. Pinealectomy performed before burning in hamsters did not prevent the burn-induced depression in serum T4 and testosterone.

Rats with a cutaneous burn exhibited a burn-size-related depression of serum thyroid hormones 2 weeks after injury. Thyroidectomized rats had a marked rise in brain in vitro T4 deiodination to T3 and in serum TSH concentration compared to controls. These normal responses to depressed thyroid hormones were not seen in burned rats. The depression of serum thyronines and thyrotrophin suggests that the burned rat may be a model for human burn injury and other nonthyroidal illness. In this model it appears that the brain and pituitary do not respond as in thyroidectomy, suggesting lack of true hypothyroidism in burn injury.

In order to assess the specific effects of inhalation injury and pneumonia on mortality in burn patients, the records of 1058 patients treated at a single institution over a five-year period, 1980-1984, were reviewed. Of these patients, 373 (35%) had inhalation injury diagnosed by bronchoscopy and/or ventilation perfusion lung scan. Of the 373 patients, 141 (38%) had subsequent pneumonia. Among the patients without inhalation injury, pneumonia occurred in 60 of 685 (8.8%). A multiple logistic equation was developed to estimate expected mortality at any age and burn size for patients without either inhalation injury or pneumonia, with either alone, or with both. Subtraction of the expected mortality without either inhalation injury or pneumonia from the expected mortality in the presence of either or both permitted the estimation of additional mortality attributable to these complications. Inhalation injury alone increased mortality by a maximum of 20% and pneumonia by a maximum of 40%, with a maximum increase of approximately 60% when both were present. The influence on mortality was maximal in the midrange of expected mortality without these complications for any age group. These data indicate that inhalation injury and pneumonia have significant, independent, additive effects on burn mortality and that these effects vary with age and burn size in a predictable manner. Reprints.