4. Surgical infections. The role of antibiotics in surgery. Flashcards
Endogenous flora variety
- Skin: gram positives
- GI-tract: mainly gram negatives
- Aerobes in special places: oesophagus, large bowel, sexual organs
Risk of infection
dose of bacterial contamination * virulence / host resistance
Some surgical infectious diseases
Osteomyelitis
Secondary peritonitis
Skin and soft tissue infections (abscesses, diabetic foot, mastitis etc.)
Intra-abdominal infections
Secondary peritonitis, due to:
Appendicitis Cholecystitis, choleangitis and liver abscesses Acute pancreatitis Duodenal perforation Large bowel perforation
Systemic risk factors of infection
Haematoma in wound: blood enables growth of bacteria Advanced age Necrotic tissue Shock: hypoperfusion and metabolic instability weakens host defence Foreign body: provide portal of entry DM Obesity Protein calorie malnutrition Contamination Alcoholism Cancer chemotherapy Immunosuppression Remote site infection
SSI
Surgical site infection
SSI categories
Divided into categories based on level of tissue penetration
Superficial/insicional
Subcutaneous abscess
Deep incisional
Factors determining need for antibiotics (SSI)
The extent of bacterial invasion into the surrounding soft tissues and/or systemic dissemination determine the need for antibiotics p.o or i.v.
General about surgical ABX prophylaxis
- reduces SSI rate by 80% = less followup care of patient needed
- cephalosporin is the first line agent, second agents are often required
- inital dose given 1h before surgery, longer surgeries need redosing
Post op therapy
Continued up until 24 hours
Longer infusions does not reduce SSIs
5 W’s of post op DDX
Wind - pneumonia (1-2d) Water - UTI (3d) Wound - post op wound infection (5d) Walk - PE (7-10d) Wonder drugs - check patients medications (anytime)
