The document discusses the modern operating room environment, describing its ideal location, design, and various zones. It emphasizes the importance of maintaining asepsis through proper ventilation, temperature/humidity control, and illumination. Various core equipment are explained, including diathermy for hemostasis and tissue manipulation, tourniquets to promote bloodless fields, and C-arms/image intensifiers to enhance surgical precision and reduce morbidity. Radiation safety measures are also outlined.

1. Inside the Operating Room
Randolph Tulsie
Medical Intern

2. Background
• Since the discovery of germs as causative agents for
various disease states much emphasis has been
placed on providing an aseptic environment of
invasive medical and surgical therapies.
• In 1867, Joseph Lister began his work on the Practices
of Asepsis in an attempt to “avoid decomposition of
the injured part”.
• His core practices included:
• Phenol Spray about operation site
• Instrument Sterilization
• Surgeon’s Hand washing

3. Background
• The modern operating room or theatre is a
purpose-built aseptic environment in which
surgical procedures are carried out by a team
of medical professionals.
• Great emphasis is placed on its design,
location, and individual components as well as
on the actions of its occupants in efforts to
maintain an optimal atmosphere for effective
surgical outcomes

4. OR Location
• Ideally all operating rooms should be grouped together in a dedicated
part of the hospital; sometimes the unit is called a operating suite.
• Positioned in close proximity to:
• Emergency Room
• ICU/HDU
• Radiology Department
• CSSU
• Blood Bank/Lab
• Limited communication with general public space such as wards and
waiting areas.

5. OR Design
• SIZE -The minimum inpatient OR size remains 400 square feet to
provide flexibility and accommodate the amount of equipment used
in traditional inpatient procedures.
• Most operating theatres are designed in theatre suites linked by a
double or single corridor.
• It is conventional to think of theatres in four zones

6. Zones of the Theatre
Outer Zone
Clean Zone
Aseptic Zone
Disposal/Contaminated Zone

8. OR Environment
• Risk of hypothermia; due to paralysis, cool IV fluids,
open wounds
• Optimal = 22 to 26oC, 40 -60% Humidity
• Affects PMMA Cement working time (2-3mins at 25oC)
Temperature
and
Humidity
• High Intensity Artificial Lighting without Shadows
• Easily adjustable, low heat outputIllumination

9. Ventilation
• Airborne Contamination accounts for about 95% of all wound
contaminations.
• Bacteria from the Skin and Upper respiratory tract can be shed by
talking and moving.
• OR Ventilation systems utilize Bacteria free air to create a positive
pressure area within the operating room.
• Clean air is fed via ceiling diffusers into the room and vented through
small vents just above the floor, as well as through an open door.
• This unidirectional flow prevents airborne bacteria from entering the
sterile field.

11. General Operating Theatre Equipment
Diathermy Tourniquets
Image
Intensifiers

12. Diathermy
• This is an electrical device used to achieve haemostasis while
dissecting tissue.
• It utilizes a high frequency Alternating Current (AC) discharged from a
handheld device to heat up body tissues within a small region; to
temperatures of up to a 1000 degrees C; vaporizing it to cut or
coagulating proteins.
• At 400kHz to 10MHz, diathermy frequencies exceed the 50hz
threshold for neurovascular stimulation.
• Two Main Types
• Monopolar
• Bipolar

13. Diathermy
Monopolar
• Circuit comprises of an active
handheld electrode and a
patient plate electrode
• Plate electrode requires at least
70cm2 contact to dry shaved
skin for safe use.
• Avoid placement on bony
prominences or metallic
implants
Bipolar
• Lower Power System which utilizes
a forceps instrument to deliver the
acting current.
• The current is passed across a small
region of tissue held between the
forceps.
• No patient Plate electrodes needed
• Allows for Precise and delicate
tissue handling

14. Diathermy Modes
• CUT – continuous low voltage
output, leads to heating up of
intracellular fluid with
subsequent vaporization and
tissue destruction

15. Diathermy Modes
• COUG – High Voltage Pulses
are administered slowly
heating up the tissue, leading
to protein denaturation and
vessel coagulation

16. Diathermy Modes

17. Tourniquets
• Compression devices used on the
extremities to promote a bloodless
field.
• Should be used with caution to
prevent irreversible tissue damage
during surgery.
• Used at Minimum pressure for
minimum time
LIMB PRESSURE TIME
Upper 50mmHg
>SBP
90
Minutes
Lower 100mmHg
>SBP
120
Minutes

18. Contraindications to Tourniquet Use
• Peripheral Arterial Disease
• Diabetes
• Predisposition to VTE
• Sickle Cell Disease
• AVMs
• Local Anaesthesia

19. C-Arm and Image Intensifiers
• The use of C-arm fluoroscopy in
intraoperative orthopaedic procedures
has become an important tool in modern
orthopaedic surgical practice.
• It enhances the technical proficiency of
the surgeon in addition to reducing the
morbidity and length of hospital stay of
the patient.

20. Fluoroscopy
• The Fluoroscopy system comprises of :
• X-ray Tube
• C arm
• Image Intensifier
• Image intensifiers are utilized to convert low energy radiation into
visible light images for image capture.
• Image intensifiers allow for high resolution images while ensuring the
lowest possible dose of radiation.

21. Image Intensifiers

22. Radiation Exposure and Safety
• Radiation exposure from the C arm is primarily through
scattered radiation off the patient during imaging.
• It is highest on the Xray tube side of the c arm near the
patient.
• Steps to reduce Exposure
• Limit Beam On Time
• Stand as far back from the patient as possible during imaging (2m)
• Ensure the C Arm is close to the patient; reduces air scatter
• Use Thyroid shields and Lead Aprons
• Reduce the use of the magnification setting
• Never be in the direct beam path