What is an operation theatre and why zones?
An operation theatre (OT) is a special room where doctors do surgery. During surgery the body is open. Germs can get in and cause infection.
So the OT is planned as zones. Each zone is cleaner than the one before.
- Protective (outer) zone: reception, changing rooms, patient waiting. Street shoes and clothes stop here.
- Clean zone: corridors, scrub area, store, recovery room. Caps, masks and OT clothes are worn.
- Sterile (aseptic) zone: the operating room itself. Only scrubbed staff in sterile gowns and gloves.
- Disposal (dirty) zone: a separate path to take out used instruments, linen and waste.
The main rule: people and clean things move inward in one direction, and dirty items leave by another route.
How an OT is organised
The room
The OT has smooth walls and floor that are easy to clean, no window that opens, and filtered air pushed in at slightly higher pressure (positive pressure), so air flows out and dust does not flow in. Temperature is kept about 20โ24 ยฐC.
Main equipment
- Operating table that can tilt and rise
- Shadow-free operating lights
- Anaesthesia machine and patient monitor (heart rate, BP, oxygen)
- Suction machine, cautery (diathermy) and instrument trolleys
- Autoclave nearby to sterilise instruments with steam
The team
- Surgeon and assistant: do the operation.
- Anaesthetist: puts the patient to sleep or numbs the area and watches vital signs.
- Scrub nurse: sterile; hands instruments, counts swabs and tools.
- Circulating nurse: not sterile; fetches things, keeps records.
- OT technician: prepares equipment, positions the patient, helps the anaesthetist.
- Housekeeping staff: clean and handle waste correctly.
Pre-operative care: before surgery
Good preparation makes surgery safer.
- Informed consent: the patient (or guardian) is told about the operation and signs.
- Tests: blood tests, blood group, ECG, X-ray as needed; allergies and medicines noted.
- Fasting: usually no solid food for about 6 hours before anaesthesia, so food does not enter the lungs.
- Skin preparation: bath, clean the area; hair is clipped only if needed.
- Remove jewellery, dentures, make-up and nail polish; identity band on the wrist.
- Surgical safety checklist: before starting, the team confirms the right patient, right side and right operation.
Post-operative care: after surgery
After surgery the patient goes to the recovery room until fully awake.
- Check airway and breathing first, then pulse, blood pressure, oxygen and temperature, often every 15 minutes at first.
- Watch the wound for bleeding; later for signs of infection (redness, swelling, pus, fever).
- Control pain with prescribed medicines.
- Keep a chart of fluids in and urine out.
- Help the patient move and breathe deeply early, to prevent clots and chest infection.
- Before going home: wound care, medicines and when to come back.
Try it at home
Wash your hands for a full 40 seconds with soap, scrubbing between fingers and under nails. A surgeon scrubs for about 5 minutes and also scrubs the forearms.
Key formulas and definitions
- Zones (outside โ inside): protective โ clean โ sterile; separate disposal zone for dirty items
- One-way flow: people and clean items move inward; used items leave by the dirty route
- Positive pressure: OT air pressure is a little higher than the corridor, so air flows out
- OT team: surgeon, assistant, anaesthetist, scrub nurse, circulating nurse, OT technician
- Pre-op: consent, tests, fasting, skin prep, ID band, safety checklist
- Post-op: airway, breathing, pulse, BP, pain, bleeding, wound infection, early movement
Worked examples
1. A visitor walks towards the operating room in outdoor shoes. Where must they be stopped, and why?
At the protective (outer) zone. Outdoor shoes carry dust and germs. In this zone people change into OT clothes and shoes before going further.
2. The scrub nurse drops a pair of forceps on the floor during surgery. What should happen?
The forceps are now unsterile and must not be used. The circulating nurse picks them up, sends them by the dirty route for cleaning and sterilising, and brings a sterile replacement. The instrument count is updated.
3. A patient had breakfast at 7 am and is planned for surgery under general anaesthesia at 9 am. What is the problem?
The stomach is not empty. Under anaesthesia, food can come up and go into the lungs. The usual advice is no solid food for about 6 hours, so a planned (non-emergency) operation should be delayed.
Common mistakes
- Thinking a mask alone makes a person sterile. Sterile means gown and gloves after scrubbing; mask and cap are for the clean zone.
- Taking used instruments back out through the clean corridor. Dirty items use the separate disposal route.
- Thinking the circulating nurse can touch the sterile field. Only the scrub team in sterile gowns can.
- Checking only the wound after surgery. Breathing and pulse are checked first.