16.1 Infection Control, Spaulding Classification & Reprocessing Standards

16.1 Infection Control, Spaulding Classification & Reprocessing Standards

In the modern operating room, infection control forms the cornerstone of perioperative patient safety. Surgical site infections (SSIs) and hospital-acquired infections (HAIs) increase patient morbidity, prolong intensive care stays, and impose billions of dollars in preventable healthcare costs. The Certified Anesthesia Technologist (Cer.A.T.T.) occupies a critical position on the perioperative team, directly managing, cleaning, testing, and reprocessing complex airway equipment, invasive hemodynamic monitoring hardware, and advanced diagnostic ultrasound devices. A failure to execute rigorous decontamination protocols compromises sterile tissue barriers and exposes vulnerable surgical patients to lethal cross-contamination, bloodborne pathogens, and multi-drug-resistant organisms.

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The Spaulding Classification System

Developed by Dr. Earle Spaulding decades ago, the Spaulding Classification System remains the framework used in Centers for Disease Control and Prevention (CDC) disinfection and sterilization guidance, and it is widely applied in device labeling and accreditation surveys, for determining the required level of medical device decontamination based on the degree of infection transmission risk.

+-----------------------------------------------------------------------------------------+
|                               SPAULDING CLASSIFICATION MATRIX                           |
+-------------------+--------------------------------+--------------------+---------------+
| Category          | Patient Contact Surface        | Anesthesia Devices | Minimum Level |
+-------------------+--------------------------------+--------------------+---------------+
| CRITICAL          | Enters sterile tissue, body    | Vascular catheters | Sterilization |
|                   | cavities, or vascular system   | Needle sets, A-line| (Complete     |
|                   |                                | transducers, biopsy| destruction   |
|                   |                                | forceps, cut-downs | of all spores)|
+-------------------+--------------------------------+--------------------+---------------+
| SEMI-CRITICAL     | Contacts intact mucous         | TEE probes, video  | High-Level    |
|                   | membranes or compromised,      | & rigid blades/    | Disinfection  |
|                   | non-intact skin                | handles, scopes,   | (HLD; destroys|
|                   |                                | airways, circuits  | all except    |
|                   |                                |                    | high spores)  |
+-------------------+--------------------------------+--------------------+---------------+
| NON-CRITICAL      | Contacts intact skin only      | BP cuffs, pulse ox | Low-to-Inter- |
|                   |                                | probes, ECG leads, | mediate Level |
|                   |                                | monitors, carts,   | Disinfection  |
|                   |                                | machine surfaces   | (Vegetative)  |
+-------------------+--------------------------------+--------------------+---------------+

Critical Items: Definition and Sterilization Mandates

Critical items are defined as any instruments or devices that enter normally sterile tissue, enter the central or peripheral vascular system, or contact circulating blood. Any microbial contamination introduced on these devices can directly seed the bloodstream or deep tissues, resulting in bacteremia, acute endocarditis, or deep wound sepsis.

In anesthesia practice, critical devices include:

• Intravascular cannulas, arterial line catheter insertion kits, and central venous catheterization (CVC) sets
• Disposable and reusable pressure transducer manifolds and dome assemblies
• Epidural and spinal needle trays, regional anesthesia echogenic block needles, and catheter sets
• Transvenous pacing wires, pulmonary artery catheter (PAC) contamination shields, and cardiac biopsy forceps
• Surgical instruments utilized for surgical airway access (cricothyrotomy and tracheostomy kits)

Reprocessing Requirement: Critical items must undergo sterilization—a validated process that completely eradicates all viable forms of microbial life, including highly resistant bacterial endospores, mycobacteria, fungi, and lipid/non-lipid viruses.

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Sterilization Modalities: Physics, Chemistry & Cycles

Sterilization in the surgical environment relies on either high-temperature thermal destruction or low-temperature chemical gaseous sterilization for heat- and moisture-sensitive components.

Steam Autoclave Sterilization

Steam autoclaving is the most dependable, cost-effective, and rapid sterilization modality. Saturated steam under pressure rapidly denatures microbial enzymes and structural proteins through coagulation.

1. Gravity Displacement Autoclaves: Saturated steam is injected into the upper chamber; because steam is lighter than ambient room air, it forces cool air downward through a temperature-sensitive discharge port at the chamber bottom.
   • Operating Parameters: 121°C (250°F) at a chamber pressure of 15 pounds per square inch (psi) for a minimum exposure time of 30 minutes.
   • Drying Cycle: Typically requires an additional 15 to 30 minutes of post-exposure exhaust to eliminate moisture from wrapped linen and instrument packs.
2. Pre-Vacuum (Dynamic Air Removal) Autoclaves: A mechanical vacuum pump actively evacuates atmospheric air from the sealed chamber before steam injection. This mechanical evacuation ensures immediate, uniform steam penetration into porous packs, lumened devices, and multi-layered instrument trays.
   • Operating Parameters: 132°C to 135°C (270°F to 275°F) at 28 to 30 psi for a minimum exposure time of 4 minutes.
   • Drying Time: 20 to 30 minutes under vacuum exhaust.

Low-Temperature Sterilization Technologies

Advanced electronic monitoring modules, fiberoptic cables, delicate plastic housings, and ultrasound crystals cannot withstand the thermal stress (134°C) or liquid condensation of steam autoclaves.

• Hydrogen Peroxide Gas Plasma (Sterrad System): Concentrated hydrogen peroxide (about 59% in STERRAD cassettes) is vaporized into an evacuated chamber under deep vacuum, surrounding the packaged devices. A radiofrequency (RF) electromagnetic energy field is then applied, ionizing the hydrogen peroxide vapor into a low-temperature gas plasma state. Highly reactive hydroxyl (OH•) and hydroperoxyl (OOH•) free radicals cleave microbial DNA, proteins, and cellular membranes.
  • Cycle Parameters: Low operating temperature (roughly 45°C to 55°C), with cycle times that vary by model and cycle (roughly 25 to 75 minutes).
  • Byproducts: Water vapor and oxygen; leaves no toxic chemical residue on devices and requires no prolonged degassing aeration phase.
  • Key Limitation: Gas plasma cannot penetrate moisture (wet items abort the cycle), long narrow dead-end lumened instruments (without approved booster adapters), or items containing cellulose (paper, cotton wraps, natural sponges, or wood pulp), as cellulose avidly absorbs peroxide and halts plasma activation.
• Ethylene Oxide (EtO) Gas Sterilization: A potent alkylating gas that chemically replaces labile hydrogen atoms within microbial proteins, enzymes, and nucleic acids with hydroxyethyl groups, halting cellular replication.
  • Cycle Parameters: Operating temperature of 37°C to 63°C (99°F to 145°F) at 40% to 80% relative humidity, with exposure times spanning 1 to 6 hours.
  • Mandatory Aeration Phase: EtO is toxic, mutagenic, carcinogenic, and explosive. Sterilized loads require 8 to 12 hours of active heated aeration at 50°C to 60°C to off-gas residual EtO from plastics, elastomers, and tubing before human handling or patient contact.

+------------------------------------------------------------------------------------------+
|                       COMPARISON OF STERILIZATION MODALITIES                             |
+---------------------+-------------------------+------------------+-----------------------+
| Modality            | Operating Parameters    | Exposure Time    | Biological Indicator  |
+---------------------+-------------------------+------------------+-----------------------+
| Gravity Steam       | 121°C (250°F) @ 15 psi  | 30 minutes       | Geobacillus           |
|                     |                         |                  | stearothermophilus    |
+---------------------+-------------------------+------------------+-----------------------+
| Pre-Vacuum Steam    | 132-135°C @ 28-30 psi   | 4 minutes        | Geobacillus           |
|                     |                         |                  | stearothermophilus    |
+---------------------+-------------------------+------------------+-----------------------+
| Gas Plasma (Sterrad)| 45-55°C (113-131°F)     | 25-75 minutes    | Geobacillus           |
|                     | H2O2 RF ionization      | (no aeration)    | stearothermophilus    |
+---------------------+-------------------------+------------------+-----------------------+
| Ethylene Oxide (EtO)| 37-63°C (99-145°F)      | 1-6 hrs exposure | Bacillus atrophaeus   |
|                     | Alkylating gas mixture  | + 8-12 hr aerate |                       |
+---------------------+-------------------------+------------------+-----------------------+

Sterilization Quality Assurance & Process Monitoring

Every sterilization cycle must be systematically verified across three distinct monitoring dimensions: physical, chemical, and biological.

1. Physical / Mechanical Monitors: Continuous printouts or digital graphs recording chamber temperature, pressure, and dwell time. Technologists must verify these cycle curves prior to releasing sterilized loads.
2. Chemical Indicators (Classes 1 through 6):
   • Class 1 (Process Indicators): External autoclave tape changing color to confirm a pack was exposed to the process, distinguishing processed from unprocessed goods.
   • Class 2 (Bowie-Dick Test): Run daily in an empty chamber of pre-vacuum steam autoclaves prior to the first processing load. Evaluates vacuum pump efficiency to detect air leaks, entrained non-condensable gases, or inadequate air evacuation that would impede steam penetration.
   • Class 5 (Integrating Indicators): React to all critical variables (time, temperature, saturated steam) and mirror the biological kill curve of Geobacillus stearothermophilus.
3. Biological Indicators (BIs): The ultimate standard of sterilization efficacy, utilizing self-contained ampoules containing millions of bacterial endospores:
   • Geobacillus stearothermophilus: Utilized for steam autoclaving and hydrogen peroxide gas plasma (Sterrad), incubated at 55°C to 60°C.
   • Bacillus atrophaeus: Utilized for ethylene oxide (EtO) and dry heat ovens, incubated at 35°C to 37°C.
   • Run at least weekly, with every implantable device load, and following any autoclave repair or maintenance.

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Semi-Critical Devices & High-Level Disinfection (HLD)

Semi-critical items are medical devices that contact intact mucous membranes or compromised, non-intact skin without penetrating sterile body cavities or entering the vascular system.

In anesthesia practice, semi-critical devices include:

• Transesophageal echocardiography (TEE) probes
• Flexible fiberoptic bronchoscopes and video intubation scopes
• Rigid and video laryngoscope blades (handles are reprocessed per the manufacturer's instructions and facility policy, often by high-level disinfection, or are single-use)
• Breathing circuits, reservoir bags, and ventilator exhalation cassettes (when reusable)
• Face masks, oral airways, nasopharyngeal airways, and intubation stylets/bougies

Reprocessing Requirement: Semi-critical items demand High-Level Disinfection (HLD). HLD destroys all vegetative microorganisms, mycobacteria (including Mycobacterium tuberculosis), fungal spores, and lipid/non-lipid viruses, but does not guarantee the destruction of high numbers of bacterial endospores.

Liquid Chemical High-Level Disinfectants

1. Ortho-phthalaldehyde (OPA 0.55%, e.g., Cidex OPA):
   • Immersion Parameters: Manual immersion for 12 minutes at 20°C (68°F), or 5 minutes at 25°C (77°F) in an Automated Endoscope Reprocessor (AER).
   • Clinical Profile: Requires no chemical activation; emits negligible vapor emissions (virtually odorless); exhibits superior microbicidal action against glutaraldehyde-resistant mycobacteria. However, OPA avidly binds to proteins, staining exposed skin, clothing, and instrument surfaces a dark gray or black.
2. Glutaraldehyde (2.4%, e.g., Cidex):
   • Immersion Parameters: 20 to 90 minutes at 20°C to 25°C (depending on the proprietary formulation and FDA clearance label).
   • Activation & Monitoring: Requires the addition of an alkaline chemical activator (sodium bicarbonate buffer) prior to use; maintains an active reuse life of 14 to 28 days. Glutaraldehyde releases pungent, noxious vapors that irritate ocular and respiratory mucosa (OSHA has no current exposure limit; NIOSH recommends a 0.2 ppm ceiling and ACGIH a 0.05 ppm ceiling), so it is used with adequate ventilation such as local exhaust or a ventilated workstation.
3. Peracetic Acid (e.g., STERIS SYSTEM 1E): A liquid oxidizing agent used in automated processors at moderately elevated temperature (roughly 46°C to 56°C) with short exposure times, breaking down into acetic acid, water, and oxygen.

Minimum Effective Concentration (MEC) Verification

Over repeated immersion cycles, chemical disinfectants become diluted by residual water on wet instruments and deactivated by organic bioburden. Therefore, the technologist must test the disinfectant's Minimum Effective Concentration (MEC) or Minimum Recommended Concentration (MRC) using chemical test strips:

• Frequency: Test and document before each use (each manual immersion or automated cycle), as most product labels require.
• Test Strip Quality Control: Test strip vials must be labeled with the date opened and date of expiration (typically 90 days after opening). Technologists must verify test strip potency using positive and negative control solutions upon opening a new bottle.
• Failure Action: If the test strip indicates that the active concentration has fallen below the MEC (e.g., Cidex OPA below 0.3%, or 2.4% glutaraldehyde below 1.5%), the chemical solution must be completely discarded and replaced immediately, regardless of its printed expiration date or calendar reuse life.

Post-HLD Rinsing Protocols

Following chemical immersion, devices retain disinfectant residue that can injure tissue (for example, glutaraldehyde colitis) or trigger allergic reactions. Follow the product label's rinse instructions; Cidex OPA manual processing, for example, calls for three separate large-volume water rinses with fresh water each time. CDC guidance permits rinsing with sterile water, filtered water, or tap water followed by an alcohol rinse and forced-air drying. Many facilities use sterile or filtered water because tap water can carry Pseudomonas aeruginosa, Legionella, and non-tuberculous mycobacteria that can recontaminate the device.

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Transesophageal Echocardiography (TEE) Probe Protocol

Transesophageal echocardiography (TEE) probes represent highly complex, delicate, and expensive semi-critical ultrasound transducers that traverse the oropharynx into the esophagus and stomach. Strict adherence to reprocessing workflows is critical to prevent device damage and catastrophic cross-contamination.

+------------------------------------------------------------------------------------------+
|                       TEE PROBE REPROCESSING WORKFLOW ALGORITHM                          |
+------------------------------------------------------------------------------------------+
                                             |
                                             v
1. POINT-OF-CARE PRE-CLEANING
   - Immediately post-procedure at patient bedside.
   - Wipe insertion tube with enzymatic sponge/cloth to strip gross mucus/blood.
   - Prevents organic bioburden and saliva from drying into an impenetrable biofilm.
                                             |
                                             v
2. VISUAL & STRUCTURAL INSPECTION
   - Inspect insertion tube for patient bite marks, deep cracks, tears, or buckling.
   - Inspect distal acoustic lens for blistering or chemical delamination.
                                             |
                                             v
3. ELECTRICAL LEAKAGE TESTING
   - Performed prior to high-level disinfection chemical immersion.
   - Submerge flexible shaft in conductive saline/water bath connected to leakage analyzer.
   - Detects insulation damage that allows leakage above the manufacturer's limit.
   - Reduces the risk of electrical injury to the esophagus and heart.
                                             |
                                             v
4. HIGH-LEVEL DISINFECTION (HLD)
   - Verify MEC of chemical solution (OPA 0.55% or glutaraldehyde 2.4%) with test strip.
   - Submerge flexible shaft ONLY up to the strain relief collar.
   - CRITICAL: Never immerse the steering control handle, articulation locks, or electrical plug.
   - Maintain exact immersion time (12 min @ 20°C for OPA).
                                             |
                                             v
5. RINSING & STERILE DRYING
   - Perform three separate rinses using copious volumes of sterile or 0.2-µm filtered water.
   - Dry thoroughly using a lint-free, sterile microfiber cloth.
                                             |
                                             v
6. TRACEABILITY & VERTICAL STORAGE
   - Document patient ID, probe serial number, chemical lot number, MEC result, operator ID.
   - Store per the IFU, typically hanging in a clean, ventilated storage cabinet.
   - Protects probe from residual moisture and room dust; prevents coiling stress on steering cables.
   - A protective sheath, if used, does not replace HLD.

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Flexible Bronchoscope & Laryngoscope Standards

Flexible Fiberoptic Bronchoscopes

Flexible bronchoscopes contain delicate suction/biopsy channels that become coated with dense tracheobronchial secretions and blood during difficult airway intubation or pulmonary isolation. Reprocessing must follow a strict sequence:

1. Point-of-Use Pre-Cleaning: Immediately after use, wipe the insertion tube and suction detergent solution through the working channel per the instructions for use.
2. Manual Leak Testing: Pressurize the inner scope chassis using a mechanical manometer bulb before wet cleaning. Submerge the pressurized scope and angulate the bending section while watching for a stream of bubbles. A positive leak test indicates an internal breach that will flood the optical fiber bundle with corrosive disinfectants during HLD.
3. Channel Brushing: Manually brush all working channels with calibrated, soft-bristled endoscope brushes until completely free of visible debris, followed by high-level disinfection, manually or in an automated endoscope reprocessor (AER).

Laryngoscope Blades and Handles

Laryngoscope handles were historically treated as non-critical items and simply wiped down, but studies have found blood and pathogens on handles after use.

Current Practice: Reusable laryngoscope blades are semi-critical devices that need high-level disinfection or sterilization between patients. Handle reprocessing follows the manufacturer's instructions for use and facility policy, and many facilities high-level disinfect or sterilize handles. Accreditation surveyors expect reprocessed blades and handles to be stored in a way that prevents recontamination, such as a sealed peel pack or a covered clean container. Many facilities use single-use blades and handles to simplify compliance.

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Non-Critical Items & Environmental Surface Decontamination

Non-critical items contact only intact skin or environmental surfaces. In the anesthesia workspace, these include non-invasive blood pressure (NIBP) cuffs, pulse oximeter finger sensors, ECG cables and lead wires, stethoscopes, intravenous infusion pumps, anesthesia machine outer panels, and anesthesia cart worktops.

Disinfectant Formulations and Dwell Times

Non-critical equipment requires low-to-intermediate level disinfection using hospital-grade, EPA-registered surface disinfectants:

• Quaternary Ammonium Compounds (Quats): Widely utilized for environmental furniture and monitors; effective against vegetative bacteria, fungi, and lipid viruses.
• 70% Isopropyl Alcohol: Rapid bactericidal action; however, it evaporates quickly, and repeated use can damage some rubber and plastic surfaces.
• Accelerated Hydrogen Peroxide (AHP): Short contact times (often 1 to 5 minutes, depending on the product), breaking down into oxygen and water.

The Wet Contact (Dwell) Time Rule: Disinfection is fundamentally dependent on chemical contact time. Technologists must verify that treated surfaces remain visibly wet for the full manufacturer-validated dwell time (listed on the product label). Wiping a surface dry prematurely terminates antimicrobial action and leaves viable pathogens on the equipment.

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Special Pathogen Focus: Clostridioides difficile (C. diff)

Clostridioides difficile is a Gram-positive, anaerobic, spore-forming bacillus responsible for severe pseudomembranous colitis, toxic megacolon, and healthcare-associated outbreaks. The management of C. diff in the operating room presents unique challenges that are heavily tested on certification examinations.

+-----------------------------------------------------------------------------------------+
|                         C. DIFFICILE INFECTION CONTROL PROTOCOLS                        |
+-----------------------------------+-----------------------------------------------------+
| Clinical Domain                   | Mandatory Infection Control Requirement             |
+-----------------------------------+-----------------------------------------------------+
| Bacterial Morphology              | Spore-forming anaerobic bacillus; produces durable  |
|                                   | keratin-like protein endospores resistant to heat.  |
+-----------------------------------+-----------------------------------------------------+
| Hand Hygiene Protocol             | SOAP AND WATER WASHING PREFERRED.                   |
|                                   | Alcohol-based hand rubs DO NOT kill endospores.     |
|                                   | Vigorous friction for at least 15-20 seconds.       |
+-----------------------------------+-----------------------------------------------------+
| Isolation Precautions             | CONTACT ENTERIC PRECAUTIONS:                        |
|                                   | Clean gown and gloves donned upon room entry.       |
+-----------------------------------+-----------------------------------------------------+
| Environmental Decontamination     | SPORICIDAL BLEACH:                                  |
|                                   | 1:10 dilution of sodium hypochlorite (5,000 ppm).   |
|                                   | Observe the label's sporicidal contact time.        |
+-----------------------------------+-----------------------------------------------------+
| Medical Equipment Management      | Dedicated single-use or disposable equipment.       |
|                                   | Reusable items wiped with sporicidal agent.         |
+-----------------------------------+-----------------------------------------------------+

The Spore Defense & The Alcohol Hand Rub Failure

Bacterial endospores possess an outer protein coat containing dense cysteine-rich keratin layers and dipicolinic acid complexed with calcium. This unique structure renders spores completely impervious to alcohol, chlorhexidine, and quaternary ammonium compounds.

Clinical Rule: Alcohol-based hand rubs do NOT destroy C. difficile spores. Applying alcohol hand sanitizer merely redistributes spores across the operator's hands. When caring for patients with confirmed or suspected C. diff enteritis, anesthesia personnel should wash hands with soap (plain or antimicrobial) and running water, using vigorous friction for at least 15 to 20 seconds. The mechanical lather and friction physically dislodge the spores from the epidermal grooves, allowing them to be rinsed down the drain.

Environmental Surface Sporicidal Cleansing

Environmental surfaces in an operating room turnover following a C. diff case cannot be cleaned with routine quat wipes. Surfaces must be decontaminated using an EPA-registered sporicidal disinfectant, most commonly a 1:10 dilution of sodium hypochlorite (household bleach, yielding 5,000 to 6,000 ppm available chlorine) or hydrogen peroxide vapor systems. The technologist must ensure that bleach solution remains visibly wet on anesthesia machine surfaces, cart tops, and cables for the full labeled contact time before wiping dry.

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Sterile Technique vs. Aseptic (Clean) Technique

The ASATT content outline asks candidates to differentiate between sterile and aseptic techniques. Both prevent infection, but they differ in goal and in where they are used.

Rules for Keeping a Sterile Field

• Check package integrity, sterilization indicators, and expiration or event-related sterility (package intact, clean, and dry) before opening.
• Open sterile wrappers away from yourself first, and treat the outer edge of the wrapper as non-sterile.
• Items below the level of the sterile field or table top are considered non-sterile.
• Keep the sterile field in view; do not leave it unattended, and a non-sterile person does not reach over it.
• Moisture that soaks through a sterile barrier (strike-through) contaminates it.

Examples the Technologist Supports

• Central venous catheter insertion: CDC guidance calls for maximal sterile barrier precautions (cap, mask, sterile gown, sterile gloves, and a sterile full-body drape) and skin antisepsis with a chlorhexidine preparation of more than 0.5% with alcohol.
• Accessing needleless connectors: CDC guidance calls for scrubbing the access port with an appropriate antiseptic (chlorhexidine, povidone-iodine, an iodophor, or 70% alcohol) and accessing it only with sterile devices.
• Neuraxial procedures: Hand hygiene, a mask, a cap, sterile gloves, and antiseptic skin preparation allowed to dry before needle insertion are standard.

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Standard Precautions, PPE & Aerosol-Generating Procedures (AGMPs)

Standard Precautions dictate that all human blood, bodily fluids, secretions, excretions (except sweat), non-intact skin, and mucous membranes are treated as potentially infectious for HIV, Hepatitis B (HBV), Hepatitis C (HCV), and other bloodborne pathogens.

Transmission-Based Isolation Categories

• Contact Precautions: Required for multi-drug resistant organisms (MRSA, VRE) and scabies. Gown and gloves required.
• Droplet Precautions: Required for influenza, pertussis, and Neisseria meningitidis. A surgical mask is worn on room entry, with eye protection as indicated by Standard Precautions.
• Airborne Precautions: Required for Mycobacterium tuberculosis, measles, varicella, and disseminated zoster. Negative-pressure airborne infection isolation room (AIIR; at least 12 air changes per hour for new construction, or 6 for older rooms) and fit-tested N95 particulate respirators or Powered Air-Purifying Respirators (PAPRs).

Aerosol-Generating Medical Procedures (AGMPs)

Endotracheal intubation, extubation, open airway suctioning, bag-valve-mask ventilation, cricothyrotomy, and bronchoscopy generate concentrated fine-particle aerosols (< 5 µm) that remain suspended in ambient air and bypass simple surgical masks. For all AGMPs in patients with known or suspect respiratory infections (COVID-19, SARS, avian influenza, tuberculosis), anesthesia technologists must don enhanced PPE: fit-tested N95 or PAPR, full face shield or goggles, fluid-resistant gown, and gloves (some protocols add double gloves). When doffing, gloves and gown are removed first (most contaminated), hand hygiene is performed, and the respirator is removed last outside the operating suite to prevent mucosal self-contamination.