Infectious Complications
Epidemiology
• Overall burn mortality ~5.3%• Age and TBSA (0.7% if TBSA <10%, 78% if TBSA 90%).• 14% Palliation• 27% MOF, 12% Burn shock, 12% Trauma, 11% Respiratory
failure• 4% sepsis burn wound
• Complications• 31% respiratory (pneumonia / ARDS)• 17% cellulitis and wound infection• 15% septicaemia and other infections
• MRSA first entered Australia through the Perth burns unit• R-Acinetobacter appeared in Concord and Perth immediately after Bali
Wound infection: Risk factors
• Extreme age• Prolonged inpatient stay• Large burns (>30% TBSA)• Full thickness burns• Improper initial burn care and failure to cover burnt area
Pathophysiology
• Breach in the immune barrier
• Skin (innate)• Avascular areas (role of debridement)• Depressed T-cell activity, decreased level of complement and cytokines,
reduced capacity of Neutrophils
Pathophysiology
• Rapid colonization by bacteria (S. aureus, Pseudomonas, Acinetobacter)• Organism present on the wound• GI tract (Gram negatives, Candida)• Hospital environment
• Biofilm after 7 days• Colonization harder to eradicate (role of early debridement)
• Fungal infection usually delayed• Anaerobes are rare (except electrical injuries)
Other infections
• Deep infections in deep burns / compartments
• Critical illness• Lines. Including infected DVT.• VAP.• Gut (compartment syndrome, Clostridium difficile).
Prevention
• Early debridement and escarrectomy• Early cover (skin graft)• Wound care
• Dressing: silver dressing• High Absorbing capacity (exsudate)• Antiseptics: Chlorhexidine, Soap, Betadine
• Immune preservation: feeding, pro-biotics
Prevention: Cochrane review
• Topical Antibacterials (decrease bacterial load)• Silver dressings: Acticoat, Aquacel Ag, Mepilex• Silver Suphadiazine
• Increased risk of infection?• Topical Antibiotics (Bacitracin, Neomycin, Polymyxin B)
• No benefit
• Systemic Antibiotics• No impact on burn infection rate
Prevention: Cochrane review
• SDD?
• No significant effect on all types of infections• Increased rate of MRSA• Burns is exclusion criteria in SuDDICU
• Rectal tubes / Zassi
Prevention
• Infection control measures
• Hand hygiene• Ante rooms. Pressurized rooms. 100%
exhaust air conditioning.• UV irradiated water. Micron filtering.• Burns unit. Dedicated burns theatre.• Staff training
Classification• Colonization
• Surface. No invasion, no systemic sign• Biopsy: usually <10e5 bacteria per gram
• Wound infection (threat to the wound, not the patient)• Wound / eschar infection without deep invasion• Biopsy: >10e5 per gram
• Invasive infection• Deeper infection, with involvement of non burned tissue and systemic response• Suppurative separation of eschar and graft loss
• Cellulitis• Inflammed tissue surrounding the burned area (not necessarily infective)
• Fasciitis / necrotizing infections• Aggressive infection of structures below the skin
Clinical signs
• Systemic response.• Sepsis is a diagnostic challenge
• Change in wound colour. Green discoloration of subcutaneous fat.
• Suppurative separation of the eschar. Graft loss with involvement of unburnt tissue
• Cellulitis
Pathogens
• S. aureus (MSSA / MRSA), Klebsiella:• Early infections
• Hospital GNR (Pseudomonas, Acinetobacter):
• Later (> 2weeks)
• Fungus: Candida, Aspegillus, Molds (Fusarium, Mucor, Rhizopus, …)
Pathogens
Diagnosis
• Differentiating SIRS from Sepsis is particularly challenging in burns patients
• PCT?
• Examination
• Culture data:• Quantitative swab / quantitative biopsy:
limited value• Histopathology: assess depth of
infection
Treatment
• Pseudomonas• Acetic Acid
• Secondary dressing• Wick exsudate from primary dressing• Exudry, Mesorb, Zetuvit, Combine
Treatment
• Systemic Antibiotics
• Adjusted dose• High VD• Augmented Renal Clearance (ARC)
• CrCl > 130 mL/min • Driven by response to infection (high CO) and treatment interventions (fluids,
vasopressors)• 82% patients will not achieve therapeutic levels with standard doses
Treatment
• Systemic Antibiotics
• Appropriate spectrum• Culture results• Pseudomonas, Acinetobacter• Piperacillin, Ticarcillin, Aminoglycosides, Carbapenems, Ceftazidim
• Multiresistant organisms• MRSA: Vancomycin, Linezolid, Daptomycin, Ceftarolin• MRAB, MRPA: Colistin, Amikacin, High dose Meropenem. Newer agents?
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