Answer:
The risk of death for a burn patient without a significant inhalation injury is highest from systemic sepsis. There are many dose-related factors that make the burn patient highly susceptible to the development of invasive sepsis. First is the burn wound itself, representing a major compromise in the body’s defense mechanism. The burn wound, in addition to being locally susceptible to infection, is associated with dose-related immunosuppression of the specific and nonspecific immune systems. Further, because these patients are often critically ill, they are subjected to a variety of invasive devices that bypass normal defense mechanisms; these devices include endotracheal tubes, bladder catheters, and arterial or venous intravascular catheters. By far the most common sites of primary infection in burn patients are the blood stream, the burn wound, the lower respiratory tract, and the urinary tract. Because of the immunocompromised state of these patients as well as their intense and long-lasting hypermetabolism, they do not exhibit the usual clinical parameters of infection found in other immunosuppressed populations (e.g. organ allograft recipients). Thus, the burn surgeon must be constantly aware of the clinical status of the patient and be alert for any subtle changes. These are often the first indicators of incipient sepsis. Careful serial clinical and laboratory monitoring of the patient is the most sensitive method of diagnosing sepsis before disastrous hemodynamic effects occur. Wound colonization with >100,000 organisms/gram tissue is an indication to perform expedient eschar excision rather than to begin antibiotics. Pseudomonas aeruginosa and Staphylococcus aureus are the dominant pathogens in burn centers. Candida species are the most commonly isolated fungal organisms.
Viral infections, particularly with cytomegalovirus, are reported with increasing frequency. There is little place for prophylactic antibiotic usage in burn patients. Penicillin G used to be recommended for the first postburn week to prevent group A beta-hemolytic Streptococcal burn wound cellulitis. There is still arguably a place for this prophylaxis if topical antibiotics are not used. There are no controlled studies that address the practice of continuous use of parenteral antibiotics. They are best reserved for use in documented infections with identified organisms.