Annals of surgery
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Mortality and morbidity in fire victims is largely a function of injury due to heat and/or smoke. While degree and area of burn together constitute a reliable numerical measure of cutaneous injury due to heat, as yet no satisfactory measure of inhalation injury has been developed. In this study, with fluid resuscitation and pulmonary infection eliminated as variables, dose-response curves were constructed as a measure of inhalation injury by exposing burned and unburned animals to smoke of constant temperature and toxicity under conditions similar to the fire situation. ⋯ While fluid resuscitation and pulmonary contamination with bacterial pathogens may be eliminated experimentally, such is not the case with the vast majority of fire victims admitted to burn services with associated inhalation injury. Fluid resuscitation and inhalation of a Pseudomonas aeruginosa aerosol were therefore included serially in a study of animals with inhalation injury and burns large enough to require fluid resuscitation. In these animals it was demonstrated that: 1) pulmonary edema occurred in association with too little rather than too much fluid therapy; 2) after aerosol inoculation, fatal bacterial pneumonia was difficult to produce when inhalation injury was associated with no or only small burns, but common when associated with no or only small burns, but common when associated with a burn large enough to require fluid resuscitation.
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The serum from 109 traumatized patients was examined for immunosuppressive activity which might explain diminished host immune responsiveness following operative or accidental injury. Twenty-eight fo 31 (90%) severely tralmatized patients, 25 of 60 (42%) moderately traumatized patients, and 0 of 18 minimally traumatized patients developed serum which suppressed the response of normal human lymphocytes to phytohemagglutinin. The degree and duration of serum immunosuppressive activity paralleled the severity of the clinical course but did not correlate with serum cortisol or barbiturate levels. ⋯ The immunosuppressive factor(s) was contained in a low molecular weight (less than 10,000 daltons) peptide fraction and was present in 5--10 times the amount recoverable from normal serum. By size and activity the trauma serum factor resembled immunoregulatory alpha globulin, a naturally-occurring serum inhibitor of T-lymphocyte reactions. Thus, depressed immunoreactivity following trauma may be due in part to high concentrations of an endogenous immunosuppressive polypeptide.