FRCA Notes

Perioperative Infection

There are a plethora of relevant curriculum items to choose from, including a whole section on infection control in the core curriculum.

For example: 'describes strategies to minimise the risk of infection in the postoperative period' and 'understands the risks of infection & applies mitigating policies & strategies'.

Resources

  • Overall, 7% of patients will suffer healthcare-associated infection after surgery
  • Infectious complications include:
    • Surgical site infections
    • Post-operative respiratory or urinary tract infections
    • Infections secondary indwelling medical devices e.g. cannulae, urinary catheters
    • Diarrhoea related to antibiotics, particularly C. difficile-associated disease
    • Other nosocomial infections
  • Surgical site infection (SSI) is a healthcare-associated infection in which a surgical incision site becomes infected
  • It accounts for up to 16% of healthcare-associated infections

  • It is common, occurring in 5-20% of patients
  • The rate of SSI varies by surgical type, e.g.:
    • <1% for orthopaedic surgery
    • >10% for large bowel surgery

  • It is associated with increased post-operative morbidity and mortality, a prolonged length of stay and increased healthcare costs

  • Most surgical wounds are likely to be contaminated by resident bacterial flora from skin or viscera
  • This may not be of clinical significance
  • Progression from contamination to clinical infection is determined by adequacy of host defence
  • The most important immune mechanism in this regard is neutrophil phagocytosis

Neutrophil phagocytosis

  • When a neutrophil ingests bacteria it undergoes a respiratory burst
  • This increases its oxygen consumption, resulting in production of anti-microbial oxygen free radicals
  • The process relies on:
    • Adequate oxygen availability
    • The function of enzymes (e.g. superoxide dismutase, myeloperoxidase) which produce said free raficals
  • Variables affecting tissue oxygen delivery or enzyme function will impair this process
  • This may allow bacteria to survive and infection to be establish


Patient factors Surgical factors
Obesity ↑ duration of surgery
Smoking Surgical cleanliness (see below)
Diabetes Use of prosthetic material
Older age Surgical technique
Malnutrition
Existing colonisation
Active infection elsewhere
Acute illness

Classification of surgical cleanliness

Classification Description
Clean Surgery that does not open body cavities (respiratory, gastro-intestinal or genito-urinary)
Surgery not associated with inflamed tissue
Clean-contaminated Surgery involving the oropharynx
Surgery involving the opening of body cavities
Contaminated Surgery involving acute inflammation, infected bilious or urinary secretions
Surgery involving bowel or wound contamination


Perioperative methods for reducing surgical site infection


Patient hygiene

  • Encourage to bathe/shower on the day prior to surgery or day of surgery
  • Give patients appropriate theatre-wear, maintaining comfort and dignity

Decolonisation

  • Consider nasal mupirocin + 4% chlorhexidine bodywash before procedures in which S. aureus is a likely cause of a surgical site infection
  • Maintain surveillance on rates of mupirocin-associated resistance
  • Do not routinely use mechanical bowel preparation

Hair removal

  • Do not routinely remove hair
  • If hair has to be removed, use electric clippers with a single-use head on the day of surgery
  • Do not use razors for hair removal, because they increase the risk of surgical site infection

Antiseptic skin preparation

  • Prepare the skin at the surgical site immediately before incision using an antiseptic preparation
  • Options include:
    • 0.5% or 2% chlorhexidine in 70% alcohol
    • 4% aqueous chlorhexidine
    • Alcohol-based 10% povidone-iodine (e.g. if chlorhexidine is contraindicated)
    • Aqueous 7.5% povidone-iodine
  • Allow to dry by evaporation and avoid pooling, especially if diathermy is being used

Antibiotic prophylaxis

  • Give antibiotic prophylaxis to those undergoing:
    • Clean surgery + placement of prosthesis/implant
    • Clean-contaminated surgery
    • Contaminated surgery

  • Give dose at induction of anaesthesia (within 30mins prior to skin incision)
    • If using a tourniquet, give earlier
    • Odds of infection increase two-fold if antibiotics are administered after incision or >60 min before incision

  • Do not use antibiotic prophylaxis routinely for clean surgery which does not involve prosthesis/implant insertion
  • Use local antibiotic formulary and take into account individual risk factors when choosing an antibiotic
  • Give a repeat dose when surgery is longer than the half-life of the antibiotic

Surgical practice

  • Wear a sterile gown
  • Use two pairs of sterile gloves if there's a high risk of glove perforation and subsequent contamination

  • If an incise drape is required, use an iodophor-impregnated drape unless the patient is allergic to iodine
  • Use of non-iodophor impregnated drapes increases risk of surgical site infection

  • Do not use diathermy for skin incision
  • Do not use wound irrigation or cavity lavage

  • Consider antimicrobial triclosan-coated sutures for closing
  • Use sutures rather than staples for closing after LSCS
  • Apply appropriate interactive dressing

Intra-operative staff practices ('theatre discipline')

  • Adherence to local infection control policies
  • Engage in appropriate hand hygiene
  • Appropriate theatre-wear (non-sterile theatre scrubs, hats, masks and overshoes)
  • Keep movements in/out of operating theatre to a minimum

Temperature management

  • Patients undergoing general or regional anaesthesia should have normothermia maintained before, during and after-surgery
  • Hypothermia triggers thermoregulatory vasoconstriction, impairing subcutaneous tissue oxygenation
  • This reduces neutrophil function in healing wounds, and can directly impair immune function

  • Even mild hypothermia (2°C below normal core temperature) can:
    • Increase wound infection rates
    • Delay wound healing

  • One exception is where active cooling is part of the surgical/therapeutic process e.g. cardiopulmonary bypass

Other perioperative homeostasis

  • Maintain adequate oxygenation to allow tissue healing (although avoid hyperoxia)
  • Maintain adequate tissue perfusion pressure

Speculative interventions to reduce infection

  • Goal-directed fluid therapy
  • Minimising blood product transfusion
  • Avoiding certain opioids (morphine, fentanyl, remifentanil)
  • ERAS protocols

Education and surveillance

  • Provide patients/carers with suitable information on:
    • Risk of infection pre-operatively
    • Wound- and dressing-care
    • Recognition of wound infection, which will prompt earlier treatment and reduce infection-related morbidity
    • Antibiotic therapy given in perioperative period
  • Surveillance of infection for both inpatients and those discharged from hospital

Early treatment

  • If wound infection occurs, prescribe antibiotics of:
    • Suitable nature to target likely pathogens
    • An appropriate duration to reduce risk of side-effects, resistance and C. difficile infection