Ch01: Asepsis & Introduction to Clinical Surgery（无菌术与外科总论）

Preparatory Mindset

Surgery begins with asepsis — the single most important concept in the entire surgical discipline, because every operation is a controlled wound and infection is its worst complication. The exam asks: definition of asepsis vs sterilization vs disinfection, the physical/chemical sterilization methods, the surgical scrubbing/dressing rules, and the "sterile vs contaminated" zones.

Exam mindset: The Chinese exam-prep PDFs drill the exact facts: "无菌术的内容包括灭菌、消毒法、操作规则、管理制度"; "应用最普遍的灭菌方法为高压蒸气法 (121–126°C, 30 min, 杀灭芽胞)"; "手术区皮肤消毒范围要包括切口周围15cm"; "无菌包保存时间2周". Know these cold.

Core Concepts

1. Asepsis — definition (MUST KNOW)

1. Sterilization (灭菌) — kill ALL microorganisms including spores (物理/化学) 2. Disinfection (消毒) — kill pathogenic microorganisms but NOT necessarily all spores (消毒法) 3. Operative rules (操作规则) — aseptic discipline during surgery 4. Management system (管理制度) — hospital infection control

• Asepsis (无菌术): a series of preventive measures against microorganisms and their routes of infection. It includes four components:
• Difference between sterilization & disinfection: sterilization eliminates ALL microorganisms (including spores); disinfection only kills pathogens (not necessarily spores)

2. Methods of sterilization (MUST KNOW)

Physical methods (物理灭菌法):

• High-pressure steam (高压蒸气法) — the most widely used; 121–126°C for 30 min → kills spores; the standard for surgical instruments/dressings
• High temperature (高温) — dry heat, boiling
• Ultraviolet (紫外线) — surface/air disinfection (does NOT penetrate)
• Ionizing radiation (电离辐射) — disposable items, implants
• Others: filtration, plasma, ethylene oxide (chemical gas sterilization for heat-sensitive items)

Chemical disinfection (化学消毒法): alcohol (75%), iodine-containing agents (碘伏), chlorhexidine, glutaraldehyde, formaldehyde — for skin, mucosa, instruments that cannot be autoclaved

3. Surgical personnel asepsis (MUST KNOW)

• Hand washing/scrubbing: surgical hand scrub (洗手) removes transient flora & reduces resident flora; duration & technique per protocol (刷手)
• Gowning & gloving (穿衣、戴手套): sterile gown & gloves; the hands once gloved must not touch non-sterile areas
• Sterile zones of the surgeon (无菌区): upper limbs, front of chest above the waist, lateral chest — the "sterile triangle"
• Contaminated zones (有菌区): back, below the waist, above the shoulders (neck/head) — hands must not cross these
• Sterile package validity: 2 weeks (无菌包保存时间2周)

4. Patient skin preparation (手术区皮肤消毒)

• Direction: from the center of the operative field outward (中心→四周) — EXCEPT for infected wounds or perianal surgery, where you go from the periphery toward the infected/anal area (外周→中心), and used swabs must not return to clean areas
• Area: skin disinfection must cover ≥15 cm around the planned incision (切口周围15cm); extend if the incision may be lengthened
• Draping (铺巾): sterile drapes isolate the operative field; only the incision area is exposed

5. Principles of aseptic technique in the OR

• All items in the sterile field must be sterile; unsterile persons/objects never touch the field
• Sterile persons face each other / the field; pass items without crossing
• The sterile field is at or above the level of the operating table; anything below waist/above shoulders is contaminated
• Skin cannot be sterilized — cover with sterile drapes; a knife blade used on skin is not reused deep
• Contamination = immediately replace drapes/instruments
• Surgical site infection (SSI) prevention: antibiotic prophylaxis timing, hair removal (clipping not shaving), normothermia, glycemic control

High-Yield Points

• Asepsis = 灭菌 + 消毒 + 操作规则 + 管理制度 (four parts)
• Most common sterilization = high-pressure steam 121–126°C × 30 min (kills spores)
• Surgeon's sterile zones: upper limbs + front chest above waist; contaminated: back, below waist, above shoulders
• Skin prep direction: center→periphery normally; periphery→center for infected/anal areas
• Disinfection area ≥15 cm around the incision
• Sterile package validity: 2 weeks
• Chemical disinfection for skin/mucosa/heat-sensitive instruments (75% alcohol, iodophor)

Topic Summary

Asepsis is the foundation of surgery — sterilization (kill everything incl. spores, most commonly by high-pressure steam 121–126°C/30 min) plus disinfection, operative rules, and management. The surgeon maintains a sterile zone (upper limbs, front chest) and avoids contaminated areas (back, below waist, above shoulders); the patient's skin is disinfected from center to periphery over ≥15 cm (reversed for infected/anal fields); sterile packages last 2 weeks. Every subsequent surgical topic (infection, wounds, SSI) builds on this.