Infectious Diseases in Critical Care Medicine

LINE SEPSIS

As in other critically ill populations, the presence of indwelling catheters for infusion

treatments provides a potential source of infection. Because of the relative frequency of

bacteremia associated with wound treatment, relative immunosuppression, and the high

concentrations of organisms on the skin often surrounding the access site for the intravascular

device, line sepsis is common in the burned patient. Santucci et al. reported an incidence of 34

catheter–related bloodstream infections per 1000 central line days in burn patients (51). It has

been well documented in other critically ill patients that the most likely portal of entry is the

skin puncture site. Ramos et al. did show a significant reduction in catheter-related infection if

the site of insertion was at least 25 cm from a burn wound (53). To date, no definitive

prospective studies have been done to determine the true incidence of catheter-related

infections related to the duration of catheterization. For this reason, most burn centers have a

policy to change catheter sites on a routine basis, every three to seven days. Vigilant and

scheduled replacement of intravascular devices presumably minimizes the incidence of

catheter-related sepsis. The first can be done over a wire using sterile Seldinger technique, but

the second change requires a new site. This protocol should be maintained as long as

intravenous access is required. Whenever possible, peripheral veins should be used for

cannulation even if the cannula is to pass through burned tissue. The saphenous vein,

however, should be avoided because of the high risk of suppurative thrombophlebitis. Should

this complication occur in any peripheral vein, the entirety of the vein must be excised under

general anesthesia with appropriate systemic therapy.

OTHER INFECTIONS

Aside from the burn wound and catheter-related infections, burn patients are also susceptible

to other infections similar to other critically ill patients (Table 3). The third most common site

would be the urinary tract because of the common presence of indwelling bladder catheters for

monitoring urine output. However, ascending infections and sepsis are uncommon because of

the use of antibiotics for other infections and prophylaxis against infection that are commonly

concentrated in the urine and thereby reduce the risk of urinary tract infection. The exception

to this is the development of funguria, most commonly fromCandidaspecies. WhenCandidais

found in the urine, systemic infection should be considered, as the organisms may be filtered

and sequestered in the tubules as a result of fungemia. The same holds true for the other fungi.

For this reason, blood cultures are indicated in the presence of funguria to determine the

source. If the infection is determined to be local, treatment with bladder irrigation of anti-

fungals is indicated. Otherwise, systemic treatment should be initiated.

Because of the relative frequency of bacteremia/fungemia in the severely burned,

sequestration of organisms around the heart valves (endocarditis) can be found on occasion. In

most large burn centers, at least one case per year of infectious endocarditis will be found on a

search for a source of infection. In fact, about 1% of severely burned patients develop this

complication. The diagnosis is generally made by the persistent finding of pathogens in the

blood, most oftenStaphylococcus orPseudomonas in the presence of valvular vegetations

identified by echocardiography (54).This should generally be confirmed with transesophageal

echocardiography if lesions are found on transthoracic echocardiography. If such a lesion is

found, routine blood cultures should be performed to identify the offending organism.

Treatment is primarily long-term intravenous antibiotics (12 weeks) aimed at the isolate. In the

presence of a hemodynamically significant valvular lesion, excision and valve replacement

Table 3 Infections in Burned Patients

Burn wound infection
Pneumonia
Catheter-related infection
Urinary tract infection
Sinusitis
Endocarditis
Infected thrombophlebitis
Infected chondritis of the burned ear

Infections in Burns in Critical Care 371