obtained with frequent irrigation with Dakin’s (sodium hypochlorite) or Domburo’s (acetic
acid) solution.
BACTEREMIA
The topical antimicrobial chemotherapeutic agents commonly applied to burn wounds are
bacteriostatic. They do not sterilize the burn wound but limit bacterial proliferation in the
eschar and maintain microbial density at levels that do not overwhelm host defenses and
invade viable tissue. Even so, manipulation of the wound by cleansing or surgical excision can
result in bacteremia. In the 1970s, before early excision became commonplace, wound
manipulation was associated with an overall 21% incidence of transient bacteremia (36). The
incidence of bacteremia, which increased in proportion to the extent of burn and the vigor of
the manipulation, provided the rationale for perioperative antibiotic administration as
described above.
The previously noted decrease in invasive bacterial burn wound infection stimulated
Mozingo et al. to reassess the incidence of bacteremia associated with burn wound cleansing
and excision procedures. In 19 burn patients, those authors found only a 12.5% overall
incidence of manipulation induced bacteremia. The incidence of bacteremia was related to
both the extent of burn and the time that had elapsed after the burn injury. Wound
manipulation in patients with burns of less than 40% of the total body surface did not elicit
bacteremia. In patients with more extensive burns, the incidence of bacteremia was 30% overall
when wound manipulation occurred on or after the 10th post-burn day and rose to 100% in
patients whose burns involved more than 80% of the total body surface (37). Those findings
can justify omission of perioperative antibiotics for patients with burns of less than 40% of the
total body surface, and perhaps even for those with more extensive burns who undergo
excision prior to the 10th day after burn.
Bacteremia may also occur in association with uncontrolled infection in other sites. In a
critically ill burn patient with life threatening complications, recovery of multiple organisms
from a single blood culture, or different organisms from successive blood cultures, indicate
severe compromise of host resistance and should not be interpreted as contamination of the
cultures. An antibiotic or antibiotics effective against all of the recovered organisms should be
administered to such a patient at maximum dosage levels and the septic source of the blood-
borne organisms should be identified and controlled. The comorbid effect of septicemia is
organism-specific. Historically, gram-negative septicemia and candidemia significantly
increased mortality above that predicted on the basis of the extent of burn, but gram-positive
septicemia had no demonstrable effect upon predicted mortality (38). Current techniques of
wound care and improvements in general care of the burn patient have not only reduced the
incidence of bacteremia but have also significantly ameliorated the comorbid effect of gram-
negative septicemia (39).
Anaerobes are very rarely isolated from the blood of burned patients. In a nine-year
study, investigators compared 4059 paired aerobic and anaerobic cultures from burned
patients and found only four anaerobic isolates (allPropionibacterium), none of which were
associated with infection. However, they noted that 46 cultures with isolated bacteria, or 13%
of those with identified bacteria, were found only in the anaerobic bottle. All of these were
obligate or facultative anaerobes. They concluded that detection of significant anaerobic
bacteremia in burned patients is very rare, and anaerobic cultures are not needed for this
purpose. However, anaerobic culture systems are also able to detect facultative and obligate
bacteria; deletion of anaerobic culture medium may have deleterious clinical impact.
SEPSIS
The diagnosis of sepsis based on clinical criteria is made commonly in the severely burned, but
the screening for the diagnosis is at times difficult. In fact, traditional signs of infection such as
elevation of white blood cells, increasing neutrophil content, or temperature elevation are not
reliable (40). Other signs such as enteral feeding intolerance, thrombocytopenia, and increasing
insulin resistance may be better signs of sepsis (41). Once the diagnosis of sepsis is secure, a
clear source of infection from the burn wound, pneumonia, or bacteremia may still be elusive.
This is usually associated with progression of multiple organ failure when a source is not
368 Wolf et al.