1.2 Operating Room Setup & Preparation

Environmental Controls

The operating room is a controlled environment engineered to minimize airborne contamination. The CST must understand the standard parameters because they appear directly on the exam:

Positive pressure means air flows OUT of the room when the door opens, preventing contaminated corridor air from entering. Humidity is kept controlled because too-low humidity raises the static-electricity/fire risk while too-high humidity promotes microbial growth and condensation. Doors stay closed and traffic is minimized; every door opening disrupts airflow and raises infection risk.

Before the first case and between cases, the room undergoes terminal/turnover cleaning. The CST assists by damp-dusting horizontal surfaces and overhead lights with a lint-free cloth before opening any sterile supplies, because dust carries microorganisms onto the sterile field.

The Case Cart and Furniture Placement

The case cart system delivers everything a specific case needs. Built from the surgeon's preference card, the cart carries the correct instrument trays, the basic and specialty packs, sutures, implants, and special supplies. The CST checks the cart against the preference card and confirms each tray's sterilization integrity — chemical indicator, intact wrapper or sealed container, and a valid integrator inside.

Furniture is positioned before opening sterile supplies. Items that will be sterilely draped — the back table, Mayo stand, ring (basin) stand, and prep/instrument tables — are grouped together and placed so the sterile field is established in the area farthest from the OR door and out of the main traffic pattern.

• The back table holds the bulk of instruments and supplies, organized systematically (sharps and prep items first, then dissectors, clamps, retractors, and specialty instruments grouped by use).
• The Mayo stand holds the small set of instruments needed for the immediate phase of the procedure; it is positioned over the patient's lower extremities and brought in from the non-operative side.
• The ring stand holds the basin used for irrigation and counting.

The CST opens supplies, gowns and gloves, sets up the field using sterile technique, performs the initial instrument, sponge, and sharps count with the circulator, and keeps the count sheet current throughout.

Equipment Checks and Electrosurgery Setup

Every piece of equipment is tested before the patient enters the room. The CST and circulator verify:

• Suction — connected, with adequate vacuum and a clean canister.
• Electrosurgical unit (ESU / "Bovie") — settings within range, alarms working, active and dispersive cords present.
• Surgical lights and headlamps — functioning, with spare bulbs available.
• OR table — articulates correctly, with attachments (stirrups, arm boards, headrest) and the table strap available.
• Monitors, tourniquet, and specialty equipment — powered and within normal limits.

Electrosurgery deserves special attention. The dispersive electrode (grounding/return pad) completes the circuit and disperses current safely back to the generator. Correct placement prevents patient burns:

• Place over a large, well-vascularized muscle mass (thigh, flank, upper arm) as close to the incision site as practical.
• Avoid bony prominences, scar tissue, excessive hair, metal implants, prostheses, pacemakers, and tattoos.
• Ensure full, even skin contact with no tenting, gaps, or wrinkles, and never reuse a single-patient pad.

If the active electrode is dropped, it is removed from the field. With everything tested and the field established, the room is ready for the patient and the time-out.

Traffic Patterns, Counts, and Room Readiness

The OR suite is divided into three traffic zones, and the CST must dress and behave accordingly:

• Unrestricted area — street clothes permitted (front desk, locker entry, control desk).
• Semi-restricted area — surgical attire and head covering required (peripheral corridors, processing, storage).
• Restricted area — surgical attire plus a mask required where sterile supplies are open or a procedure is underway (the operating room itself, scrub sink area).

Before the case, the CST and circulator perform the initial surgical count of sponges, sharps, and instruments. Counts are done together, audibly, and in a consistent order; they are repeated before closure of a cavity, at the start of wound closure, and at skin closure, plus whenever staff are relieved. The count protects against a retained surgical item (RSI), itself a never event. If a count is incorrect, the team searches, the surgeon is notified, and an X-ray is obtained before the patient leaves.

Room-readiness setup also includes confirming patient-specific items: warming devices and IV fluid warmers, sequential compression devices (SCDs) for venous-thromboembolism prophylaxis, the correct positioning attachments for the planned case, and any imaging (C-arm) or implants. The CST verifies expiration dates and the sterilization indicators on every package opened. A methodical, standardized setup means that when the patient is wheeled in, anesthesia, positioning, prep, draping, and the time-out flow without delay — and a smooth setup directly reduces anesthesia time and infection risk.

Throughout, the CST keeps the sterile field within view and never leaves it unattended once supplies are open, because an unmonitored field is considered unreliable and must be re-evaluated.