General Surgery
Surgical Infections, Asepsis and Operation Theatre
MBBS surgery notes on surgical infections, asepsis, sterilisation and operation theatre discipline, including necrotising fasciitis, mapped to NMC codes SU6, SU14 and SU15.
MedNext Academy | 3 min read
Surgical Infections, Asepsis and Operation Theatre
MBBS surgery notes on surgical infections, asepsis, sterilisation and operation theatre discipline, including necrotising fasciitis, mapped to NMC codes SU6, SU14 and SU15.
This combined chapter covers surgical infections, the principles of asepsis and antisepsis, and the safe running of the operation theatre. It links sterilisation methods and theatre discipline to the prevention and treatment of surgical site and soft tissue infections.
High-yield: Surgical Infections, Asepsis and Operation Theatre
- Asepsis means keeping an area free of microorganisms, while antisepsis reduces organisms on living tissue with agents such as chlorhexidine and povidone iodine.
- Sterilisation destroys all microbes including spores; autoclaving with saturated steam under pressure is the standard for surgical instruments.
- Standard autoclaving is 121 degrees Celsius at 15 pounds per square inch for 15 minutes, or 134 degrees for a shorter cycle.
- Heat-sensitive items such as endoscopes are sterilised with ethylene oxide gas or low temperature plasma.
- Surgical site infection usually appears around the fifth postoperative day with pain, redness, warmth, swelling and discharge.
- Prophylactic antibiotics should be given within 60 minutes before the skin incision to reach tissue levels at the time of contamination.
- An abscess is a walled collection of pus and its cardinal treatment is drainage, as antibiotics alone rarely cure it.
- Cellulitis is a spreading infection of skin and subcutaneous tissue, commonly caused by Streptococcus pyogenes and Staphylococcus aureus.
- Necrotising fasciitis is a surgical emergency with pain out of proportion to signs, crepitus and rapid spread, needing urgent wide debridement.
- Fournier gangrene is necrotising fasciitis of the perineum and scrotum, often in diabetics, and carries a high mortality.
- Gas gangrene from Clostridium perfringens produces crepitus, foul discharge and toxaemia and requires debridement, penicillin and sometimes hyperbaric oxygen.
- Tetanus prophylaxis depends on the wound type and the patient immunisation status, with tetanus immunoglobulin for tetanus-prone wounds in the unimmunised.
- Laminar airflow, restricted theatre traffic and correct ventilation reduce airborne contamination in the operating theatre.
- Surgical hand antisepsis, sterile gowns and gloves, and skin preparation form the sterile barrier against wound contamination.
- Hospital-acquired infections such as methicillin-resistant Staphylococcus aureus are reduced by hand hygiene, isolation and antibiotic stewardship.
Asepsis, antisepsis and sterilisation
- **Antisepsis:** Reduces microbes on living tissue using agents such as chlorhexidine and povidone iodine.
- **Disinfection:** Removes most microbes from inanimate surfaces but may not kill spores.
- **Sterilisation:** Destroys all microbes including spores; autoclave for instruments, ethylene oxide for heat-sensitive items.
- **Antibiotic prophylaxis:** Given within 60 minutes before incision to cover the moment of contamination.
NMC competencies in this chapter
- **SU6.1:** Surgical infections: types, presentation and management
- **SU6.2:** Principles of wound care and antibiotic prophylaxis
- **SU5.3:** Classification of surgical wounds by contamination
- **SU14.1:** Asepsis and antisepsis: definitions and agents
- **SU14.2:** Methods of sterilisation and disinfection
- **SU14.3:** Surgical hand antisepsis and sterile technique
- **SU14.4:** Prevention of surgical site infection
- **SU15.1:** Operation theatre design, ventilation and discipline
- **SU18.1:** Soft tissue infections and their management
Frequently Asked Questions
What is the difference between asepsis, antisepsis and sterilisation?
Asepsis keeps an area free of microbes, antisepsis reduces microbes on living tissue with agents like chlorhexidine, and sterilisation destroys all microbes including spores, as with autoclaving.
How does an autoclave sterilise instruments?
It uses saturated steam under pressure, typically 121 degrees Celsius at 15 pounds per square inch for 15 minutes, which reliably kills bacteria, viruses, fungi and spores.
What is the key treatment of an abscess?
Drainage of the pus is the cardinal step. Antibiotics alone rarely cure a walled collection, so incision and drainage is required, with antibiotics as an adjunct where indicated.
How is necrotising fasciitis recognised and treated?
It presents with pain out of proportion to the signs, crepitus and rapid spread with systemic toxicity, and it needs urgent wide surgical debridement plus broad-spectrum antibiotics.
Continue reading
MBBSAll General Surgery chapters
Continue through the General Surgery chapter map.
Continue studying General Surgery
Explore clinician-written learning resources, structured revision and practice across the MedNext platform.
Open in the MedNext appSee plans