1.6 Sterile Field Setup and Draping

The creation and maintenance of the sterile field are the absolute responsibility of the surgical team. The sterile field encompasses the patient, the operating table, the Mayo stand, the back table, the ring stands, and any scrubbed personnel. Establishing this field correctly dictates the safety of the entire procedure. As a CSFA, vigilance and adherence to the principles of asepsis are paramount.

Principles of Sterile Setup

The sterile field should be opened as close to the time of the surgery as possible. An open sterile field left unattended or exposed for prolonged periods is at a high risk of airborne contamination. If a delay occurs, the field may be covered with a sterile drape according to facility policy, but continuous observation is preferred.

When setting up the back table and Mayo stand, the CSFA must ensure they are positioned at least 12 to 18 inches away from walls, cabinets, and unsterile equipment to prevent accidental contact. Only sterile items may be placed within the sterile field. When the circulator opens wrapped items, the wrapper edges are considered unsterile; the one-inch border around the perimeter of any sterile wrapper or drape is universally considered unsterile.

Movement in and around the sterile field is strictly regulated. Scrubbed personnel are considered sterile only in front, from the chest to the level of the sterile field (usually the table height), and from the gloved hands to two inches above the elbows. Therefore, scrubbed personnel must pass each other either front-to-front (sterile to sterile) or back-to-back (unsterile to unsterile). A scrubbed person must never turn their back on the sterile field.

Creating the Sterile Field on the Patient: Draping

Draping is the process of applying sterile barriers over the patient and the operating table to isolate the prepared surgical site from the unsterile surrounding areas. Drapes are typically made of fluid-impervious, lint-free, and flame-retardant materials.

Rules of Draping

Several unbreakable rules govern the draping process to ensure sterility:

1. Handle drapes as little as possible: Excessive shaking or unfolding creates air currents that can lift dust and microbes onto the sterile field.
2. Drape from the incision site to the periphery: Drapes are placed initially at the planned incision site and then opened outward.
3. Never reposition a drape: Once a drape is placed on the patient, it can only be moved further away from the incision site, never toward it. Moving a drape toward the incision drags unsterile skin flora into the clean zone. If a drape is misplaced, it must be discarded by the circulator and replaced.
4. Protect the gloved hands: When placing a drape, the CSFA should cuff the drape over their gloved hands to protect them from touching the unsterile patient skin.
5. Hold drapes above waist level: A drape that falls below the waist level or touches the floor is contaminated and must be discarded.

Sequence of Draping

The sequence of draping varies based on the procedure, but a standard laparotomy draping sequence illustrates the core concepts.

First, four sterile towels are placed around the incision site to square it off. These towels are secured with non-perforating towel clips or have adhesive backing. The first towel is placed on the side of the patient nearest the person draping, to avoid reaching over the unsterile table. The subsequent towels are placed superiorly, inferiorly, and finally on the opposite side.

Next, a waterproof, adhesive incision drape (such as an Ioban) may be placed directly over the squared-off area to seal the skin and prevent microbes from migrating to the surface during the surgery.

Finally, the main laparotomy drape—a large fenestrated sheet (a sheet with a pre-cut opening)—is applied. The CSFA and the surgeon carry the folded drape to the patient, align the fenestration over the squared-off incision site, and allow the upper and lower halves to fall over the patient's head and feet. The anesthesia provider at the head of the bed receives the top end of the drape to attach to the anesthesia screen, completing the sterile barrier.

Managing the Sterile Field

Once established, maintaining the sterile field is an active, continuous process. The CSFA must monitor the field for any breaks in technique. If a sterile item falls to the floor, it is contaminated. If a sterile glove is punctured by a needle, it must be changed immediately. If a sterile drape becomes soaked with blood or saline (a phenomenon known as strike-through), it becomes a conduit for bacteria from the unsterile surface below and must be covered with an impermeable sterile barrier or replaced.

The golden rule of asepsis dictates: "If in doubt, throw it out." Any hesitation regarding the sterility of an item or a surface means it must be considered contaminated. Adherence to these strict standards ensures that the patient is protected from devastating postoperative infections.