such as second-degree wounds. It also can cause an allergic skin rash and has carbonic
anhydrase inhibitory characteristics that can result in a metabolic acidosis when applied over
large surfaces. For these reasons, mafenide acetate is typically reserved for small full-thickness
injuries, wounds with obvious bacterial overgrowth, or in those full-thickness wounds that
cannot be rapidly excised, such as in patients with concomitant devastating head injuries.
Petroleum-based antimicrobial ointments with polymyxin B, neomycin, and bacitracin
are clear on application, painless, and allow for easy wound observation. These agents are
commonly used for treatment of facial burns, graft sites, healing donor sites, and small, partial-
thickness burns. Mupirocin is another petroleum-based ointment that has improved activity
against gram-positive bacteria, particularly methicillin-resistant Staphylococcus aureusand
selected gram-negative bacteria. Nystatin, either in a salve or powder form, can be applied to
wounds to control fungal growth. Nystatin-containing ointments can be combined with other
topical agents to decrease colonization of both bacteria and fungus. The exception is the
combination of nystatin and mafenide acetate because each will inactivate the other.
Available agents for application as a soak include 0.5% silver nitrate solution, 0.025%
sodium hypochlorite (Dakin’s), 5% acetic acid (Domburo’s), and most recently mafenide
acetate as a 5% solution. Silver nitrate has the advantage of painless application, and almost
complete antimicrobial coverage. The disadvantages include its staining of surfaces to a dull
gray or black when the solution dries. This can become problematic in deciphering wound
depth during burn excisions and in keeping the patient and surroundings clean of the black
staining with exposure to light. The solution is hypotonic as well, and continuous use can
cause electrolyte leaching, with rare methemoglobinemia as another complication. Dakin’s is a
basic solution with effectiveness against most microbes; however, it also has cytotoxic effects
on the patients wounds, thus inhibiting healing. Low concentrations of sodium hypochlorite
have less cytotoxic effects while maintaining the antimicrobial effects in vitro. In addition,
hypochlorite ion is inactivated by contact with protein, so the solution must be continually
changed either with frequent application of new solution or continuous irrigation. The same is
true for acetic acid solutions; however, this solution may be more effective against
Pseudomonas, although this may only be a discoloration of pyocyanine released by this
organism without effect on its viability. Mafenide acetate soaks have the same characteristics of
the mafenide acetate salve but are not recommended for primary treatment of intact eschar.
It must be stated that all topical agents inhibit epithelialization of the wound to some
extent, presumably due to toxicity of the agents to keratinocytes and/or fibroblasts,
polymorphonuclear cells, and macrophages. Therefore, these agents should be used with
this in mind. The alternative of wound infection occurring in an untreated wound, however,
justifies the routine use of topical agents.
The use of perioperative systemic antimicrobials also has a role in decreasing burn
wound sepsis until the burn wound is closed. Common organisms that must be considered
when choosing a perioperative regimen includeStaphylococcusandPseudomonasspecies, which
are prevalent in wounds. After massive excisions, gut flora are often found in the wounds,
mandating consideration of these species as well, particularly Klebsiella pneumoniae.
Perioperative antibiotics clearly benefit patients with injuries greater than 40% TBSA burns,
as described below.
The use of perioperative antibiotics has been linked to the development of multiple
resistant strains of bacteria and the emergence of fungi in several types of critical care units.
Considering this and other data, we recommend that systemic antibiotics should be used short
term (24 hours) routinely as perioperative treatment during excision and grafting because the
benefits outweigh the risks. We use a combination of vancomycin and amikacin for this
purpose, covering the two most common pathogens on the burn wound, i.e.,Staphylococcus
andPseudomonas. The preferred perioperative regimen includes 1 g of vancomycin given
intravenously one hour prior to surgery, and another gram 12 hours after the surgical
procedure, and a dose of amikacin (based on patient weight, age, and estimated creatinine
clearance) given 30 minutes prior to surgery and again eight hours after surgery. Next,
systemic antibiotics should be used for identified infections of the burn wound, pneumonia,
etc. The antibiotics chosen should be directed presumptively at multiply resistantStaphylo-
coccusandPseudomonasand other gram-negatives. The antibiotic regimen is modified if
necessary on the basis of culture and sensitivity results.
362 Wolf et al.