3.1 Postoperative Wound Care & Dressing

CDC Surgical Wound Classification (I-IV)

The Centers for Disease Control and Prevention (CDC) classifies every surgical wound into one of four categories based on the degree of microbial contamination present in the operative field. The class predicts the risk of surgical site infection (SSI) and is documented by the circulator on the operative record. Surgical technologists must recognize the class because it influences glove/instrument changes, irrigation, and whether the wound is closed primarily or left open.

A key exam distinction: a major break in sterile technique automatically upgrades a Class I or II case to Class III, even if the anatomy entered would otherwise have been cleaner.

Wound Healing by Intention

The CST should understand how the wound will close, because it dictates dressing choice.

• First (primary) intention — Wound edges are approximated with sutures, staples, or adhesive; minimal tissue loss; heals quickly with a thin scar. Most clean elective incisions heal this way.
• Second intention — The wound is left open to heal from the base upward by granulation and contraction; used for infected or tissue-deficient wounds (Class III/IV). Requires packing, not simple closure.
• Third intention (delayed primary closure) — The wound is intentionally left open for a period (often to control infection or edema), then surgically closed several days later. Combines features of first and second intention.

Surgical Drains

Drains evacuate blood, serum, pus, or air from a wound to prevent fluid collection (seroma/hematoma) that would delay healing and harbor infection.

Closed systems reduce retrograde contamination versus the open Penrose, so they are preferred when infection control is critical. A drain is generally placed through a separate stab incision near, but not through, the main incision line.

The Layered Surgical Dressing

A standard postoperative dressing is built in three functional layers, applied by the scrub before the patient leaves the sterile field:

1. Contact (primary) layer — A nonadherent material (e.g., Telfa, petrolatum/Xeroform gauze) placed directly on the incision to protect new tissue and avoid disrupting it at removal.
2. Intermediate (absorbent) layer — Gauze (4x4s, ABD/abdominal pads) that wicks and holds wound exudate.
3. Outer (securing) layer — Tape, transparent film (e.g., Tegaderm), or roller bandage (Kerlix, Ace wrap) that holds the dressing and may provide light compression.

Other dressing types tested on the CST exam include the pressure dressing (controls bleeding/dead space, reduces edema), the occlusive dressing (airtight/watertight seal, used over chest tubes), the bolster/stent dressing (ties over grafts to immobilize them), and the wet-to-dry dressing for mechanical debridement of open wounds. A specialized form is negative-pressure wound therapy (NPWT), sometimes called a wound VAC, which applies continuous subatmospheric pressure to draw out exudate and promote granulation in complex or chronic wounds.

Phases of Wound Healing

The CST should also recognize the three overlapping physiologic phases of healing, because surgical site infection and dehiscence interrupt them:

1. Inflammatory (lag) phase — Days 1-4; hemostasis (vasoconstriction, clot formation), then vasodilation brings leukocytes to clear debris. The wound is weakest here.
2. Proliferative phase — Days 5-20; fibroblasts lay down collagen, new capillaries form (angiogenesis), and granulation tissue and epithelium develop.
3. Maturation (remodeling) phase — Weeks to months; collagen reorganizes and tensile strength increases, though the scar never regains 100% of original strength.

Dehiscence (partial/total separation of the wound layers) and evisceration (protrusion of viscera through the incision) are postoperative emergencies most likely in the early inflammatory phase, particularly in contaminated or poorly nourished patients.

Sequence and Sterile Technique

While the scrub still has sterile gloves on, the contact layer is placed directly on the incision; the circulator may then secure the outer tape after the drape edge is reflected. Dressing supplies are opened onto the field before the count is finalized so the surgeon is never left waiting, but the dressing itself is the last step before the patient is transferred. Skin around the incision is cleaned of blood and prep solution, and the dressing is applied without dragging contaminated tape across the fresh suture line.