Your FREE CST Flashcards 2026 – 200+ Cards

CST Flashcards

Sterile field

An area created with sterile drapes and supplies around the surgical site; only sterile items and sterile-gowned/gloved persons may contact it.

Asepsis

The absence of pathogenic microorganisms. Surgical (sterile) asepsis aims for the total absence of all microbes on the sterile field.

Surgical conscience

The professional honesty and self-discipline to maintain sterile technique and report any break in sterility, even when no one else sees it.

Time-out (Universal Protocol)

A pause before incision where the whole team verifies correct patient, correct procedure, and correct site/side to prevent wrong-site surgery.

What is the CST credential?

Certified Surgical Technologist — the NBSTSA credential for the surgical technologist who prepares the OR and assists during surgery, primarily in the scrub role.

Sterile to sterile rule

Only sterile items may touch other sterile items. If a sterile item contacts anything unsterile, it is contaminated.

1-inch (2.5 cm) margin rule

The outer 1 inch around the edge of a sterile drape or wrapper is considered unsterile (the boundary zone).

Gown sterile zones

A sterile gown is sterile only from the chest/nipple line to the level of the sterile field (waist) in front, and the sleeves from 2 inches above the elbow to the cuff.

Why keep hands above waist and in sight?

Anything below the waist/table level or out of sight is considered unsterile; the sterile field is only chest-to-waist height.

Strike-through contamination

Moisture wicking through a drape, gown, or wrapper that carries microbes from an unsterile surface to a sterile one, contaminating it.

Surgical hand scrub purpose

Mechanically and chemically removes soil and transient microbes and reduces resident flora on the hands and forearms before gowning and gloving.

Counted brush-stroke vs timed scrub

Two accepted surgical scrub methods: a counted number of brush strokes per finger/surface, or a timed scrub (typically 2–5 minutes per facility policy).

Scrub: hands vs elbows position

Keep hands above the elbows during and after the scrub so water runs from the cleanest area (fingertips) down toward the elbows.

Closed gloving

The preferred self-gloving method: hands stay inside the gown sleeves/cuffs while pulling on gloves, so bare skin never touches the glove's outside.

Open gloving

Gloving where fingers protrude through the cuffs; used for procedures not requiring a full gown (e.g., Foley insertion) or to change a single glove.

Skin antiseptic prep direction

Prep from the incision site outward in expanding circles toward the periphery — clean to dirty — and never return a used sponge to the center.

Common skin prep agents

Chlorhexidine gluconate (CHG), povidone-iodine (Betadine), and alcohol-based preps; CHG has longer residual activity.

Pooling of prep solution risk

Alcohol-based preps pooling under drapes are a fire hazard and can cause skin burns; allow full drying before draping/electrosurgery.

Hair removal at surgical site

Remove hair only if it interferes with the procedure, using clippers (not a razor) immediately before surgery to reduce skin-nick infection risk.

Patient identification before surgery

Verify the patient with at least two identifiers (name + date of birth), the consent, the procedure, and the surgical site/side.

Supine position

Lying flat on the back; the most common surgical position, used for abdominal, cardiac, and many general procedures.

Trendelenburg position

Supine with the head lower than the feet; used for lower-abdominal/pelvic surgery to shift bowel cephalad. Watch for respiratory compromise.

Reverse Trendelenburg

Supine with the head higher than the feet; used for upper-abdominal, head/neck, and thyroid surgery.

Lithotomy position

Supine with legs raised and abducted in stirrups; used for gynecologic, urologic, and rectal procedures. Raise/lower both legs together.

Prone position

Lying face down; used for spine and posterior procedures. Protect the eyes, face, breasts, and genitalia, and support the chest.

Lateral (Sims') position

Lying on one side; used for kidney, hip, and thoracic procedures. Place an axillary roll to protect the brachial plexus.

Fowler's position

Sitting/semi-sitting; used for some cranial, shoulder, and nasopharyngeal procedures. Risk of venous air embolism.

Positioning injury prevention

Pad bony prominences and nerves, maintain body alignment, avoid pressure on the eyes and genitalia, and protect the brachial plexus and peroneal nerve.

Most commonly injured nerve in lithotomy

The common peroneal nerve (from stirrup pressure at the lateral knee/fibular head), causing foot drop.

Purpose of the safety strap

A restraint placed ~2 inches above the knees on the supine patient to prevent falls; never so tight it impairs circulation.

Scrub (sterile) role

The CST who maintains the sterile field, sets up the back table/Mayo, passes instruments, and tracks counts during the procedure.

Circulator (non-sterile) role

The RN/team member outside the sterile field who manages the room, obtains supplies, documents, and assists with counts and patient care.

Mayo stand

A small sterile stand placed over the patient holding the instruments in immediate use during the procedure.

Back table

The large sterile table holding the bulk of the instruments, sponges, sutures, and supplies organized by the scrub.

First (initial) count timing

Sponges, sharps, and instruments are counted by the scrub and circulator before the procedure (baseline), and recorded.

When are surgical counts required?

Before the procedure (initial), before closure of a cavity, before wound (skin) closure, and whenever staff is relieved — plus any time counts are in question.

Action for an incorrect count

Notify the surgeon, recount, search the field/floor/trash/drapes, and obtain an X-ray if the item is not found; document everything.

Radiopaque sponge

Surgical sponges contain a radiopaque marker so a retained sponge shows up on X-ray; never use them as dressings.

Retained surgical item (RSI)

A 'never event' — an item (sponge, needle, instrument) unintentionally left in the patient; counts exist to prevent it.

Neutral / no-touch zone

A designated tray or magnetic mat for passing sharps hands-free between scrub and surgeon to prevent sharps injuries.

Scalpel handle / blade pairings

A #3 handle takes #10, #11, #12, and #15 blades; a #4 handle takes the larger #20–#23 blades.

#10 blade vs #15 blade

#10 = a large curved belly for long skin incisions; #15 = a small curved blade for short, precise incisions.

#11 blade

A sharp, pointed (stab) blade used for incising abscesses, making arteriotomy/stab incisions.

Loading a blade safely

Use a needle holder (not fingers), grasp the dull (non-cutting) edge, and slide the blade onto the handle's groove pointing away from yourself.

Cutting instruments (examples)

Scalpels, Mayo scissors (heavy/suture), Metzenbaum scissors (delicate tissue), and bandage scissors.

Mayo vs Metzenbaum scissors

Mayo = heavier, for cutting suture and dense tissue; Metzenbaum ('Metz') = lighter and longer, for fine/delicate tissue dissection.

Grasping/holding instruments

Forceps (thumb/pickups), Allis, Babcock, Kocher (Ochsner), and tenacula — used to hold or retract tissue.

Allis vs Babcock

Allis = teeth that grasp tissue firmly (e.g., to be removed); Babcock = atraumatic, rounded ends for delicate/tubular structures like bowel.

Hemostatic clamps (occluding)

Hemostats (mosquito, Crile, Kelly), Rochester-Pean, and right-angle (Mixter) clamps used to clamp bleeding vessels.

Mosquito vs Kelly vs Crile

Mosquito = smallest, fine bleeders; Crile = fully serrated jaws; Kelly = partially serrated jaws; size increases mosquito < Crile/Kelly < Pean.

Needle holder (driver)

An instrument that grasps and drives a curved suture needle; load the needle 1/2 to 2/3 from the tip, in the holder's jaw tip.

Retractors: handheld vs self-retaining

Handheld (Army-Navy, Richardson, Deaver, malleable) held by an assistant; self-retaining (Weitlaner, Balfour, Bookwalter) hold themselves open.

Probing/dilating instruments

Probes, grooved directors, and dilators (e.g., Hegar, Bakes) used to explore or enlarge a structure or duct.

Suction tips

Yankauer (tonsil) for the oropharynx/large volumes; Poole (with guard) for abdominal cavities; Frazier for delicate neuro/ENT fields.

Passing instruments to the surgeon

Pass firmly into the surgeon's palm in the ready-to-use position so they need not look away from the field; pass curved instruments curve-down.

Box lock

The hinge joint of a ringed instrument where the two halves cross; inspect and clean it because debris collects there.

Ratchet

The interlocking teeth on the finger rings of a clamp/needle holder that lock the jaws closed at set tensions.

Serrations

The grooves on instrument jaws that improve grip on tissue or suture; transverse, longitudinal, or cross-hatched.

Tissue (toothed) vs smooth forceps

Toothed (rat-tooth/Adson) grip skin/tough tissue; smooth/non-toothed forceps handle delicate tissue (bowel, vessels) atraumatically.

Sponge stick (sponge forceps)

A ring forceps holding a folded sponge, used for prepping, blunt dissection, or absorbing fluid in a deep cavity.

Absorbable suture (examples)

Surgical gut (plain/chromic), polyglactin 910 (Vicryl), poliglecaprone (Monocryl), polydioxanone (PDS) — broken down by the body over time.

Non-absorbable suture (examples)

Silk, nylon (Ethilon), polypropylene (Prolene), polyester, and stainless steel — remain or are removed; used where lasting strength is needed.

Suture sizing (USP)

The more zeros, the smaller the suture: 2-0 is larger than 5-0; sizes range from heavy (#5) down to very fine (11-0).

Monofilament vs multifilament suture

Monofilament = single strand, less tissue drag and lower infection harbor; multifilament (braided) = stronger handling but more capillarity.

Tie / ligature / free tie

A strand of suture used to tie off (ligate) a blood vessel; a 'free tie' is handed without a needle; a 'tie on a passer' is on a clamp.

Swaged (atraumatic) needle

A suture permanently attached to the needle (no eye), so a single strand passes through tissue — atraumatic.

Cutting vs tapered needle

Cutting needles (sharp edges) for tough tissue like skin/fascia; tapered (round body) needles for soft tissue like bowel and vessels.

Surgical stapler uses

Devices that place rows of staples for skin closure, GI anastomosis (GIA/TA/EEA), and ligation — faster than hand-suturing.

Surgical sponges (types)

Raytec (4-by-4-inch, radiopaque), laparotomy ('lap') sponges, Kittner/peanut dissectors, and cottonoids (neuro) — all counted.

Drain purpose (Penrose, JP, Hemovac)

Drains evacuate blood/fluid from a wound; Penrose = passive; Jackson-Pratt and Hemovac = closed active (suction) systems.

Electrosurgery (ESU / 'Bovie')

Uses high-frequency current to cut tissue and coagulate (stop) bleeding; cutting = continuous current, coagulation = intermittent.

Monopolar vs bipolar electrosurgery

Monopolar = current flows from the active electrode through the patient to a dispersive (grounding) pad; bipolar = current passes only between the two forceps tips (no pad).

Dispersive (grounding) pad placement

Place over clean, dry, well-vascularized muscle close to the site; avoid bony prominences, scars, implants, and hair to prevent burns.

Surgical smoke (plume) hazard

Electrosurgery/laser smoke can carry viable cells, viral DNA, and toxins; use a smoke evacuator and high-filtration masks.

Pneumatic tourniquet purpose

Creates a bloodless field on an extremity; record inflation pressure and time, and limit time (often up to 60 min upper / 90 min lower limb) to avoid nerve/tissue injury.

Estimated blood loss (EBL)

The amount of blood lost during surgery, estimated by weighing sponges, measuring suction canisters, and observing drapes.

Hemostatic agents (chemical/mechanical)

Gelfoam, Surgicel (oxidized cellulose), thrombin, bone wax, and microfibrillar collagen — promote clotting at the bleeding site.

Specimen handling

Identify, keep correct (often do NOT place gross specimens in formalin until verified), label with patient/site, and hand off to the circulator promptly; never let a specimen dry out unless ordered.

Frozen section specimen

A specimen sent fresh (NOT in formalin) for rapid pathology while the patient is still under anesthesia to guide the procedure.

Culture specimen handling

Specimens for culture and sensitivity are placed in the appropriate sterile container/medium (aerobic/anaerobic), not formalin.

Laparoscopy (MIS)

Minimally invasive surgery through small ports using a camera (laparoscope) and long instruments; the abdomen is insufflated with CO₂.

Why CO₂ for insufflation?

Carbon dioxide is noncombustible, highly soluble in blood (so emboli are rare), and inexpensive — used to create pneumoperitoneum.

Veress needle vs Hasson

Veress needle = closed insufflation entry; Hasson (open) technique = direct visualized port placement; both establish pneumoperitoneum.

Trocar

A sharp/blunt-tipped instrument within a cannula used to puncture the body wall and create a port for laparoscopic instruments.

Endoscope vs laparoscope

An endoscope views a hollow organ/cavity through a natural orifice; a laparoscope is the scope used through ports for abdominal MIS.

Robotic surgery role of the CST

Sets up sterile instrument arms, drapes the robotic arms, exchanges instruments, and assists at the bedside while the surgeon operates from a console.

Laser safety

Wear wavelength-specific eye protection, post warning signs, cover windows, use non-reflective instruments, keep water/saline ready, and protect the airway from ignition.

C-arm (fluoroscopy) safety

Wear lead aprons/thyroid shields, increase distance from the source, and minimize exposure time (time, distance, shielding).

Hemostasis methods (mechanical)

Pressure, ligatures, suture ligation, clips, staples, bone wax, and tourniquet — physical means to stop bleeding.

Hemostasis methods (thermal)

Electrosurgery, laser, argon beam coagulation, and harmonic (ultrasonic) scalpel — use energy to coagulate tissue.

Surgical wound classification I

Class I — Clean: uninfected, no inflammation, respiratory/GI/GU/oropharyngeal tracts not entered (e.g., a hernia repair).

Surgical wound classification II

Class II — Clean-contaminated: a controlled entry into the respiratory/GI/GU tract without unusual contamination (e.g., elective cholecystectomy).

Surgical wound classification III

Class III — Contaminated: open fresh wounds, major break in sterile technique, or gross GI spillage.

Surgical wound classification IV

Class IV — Dirty/infected: old traumatic wounds with retained devitalized tissue, or existing clinical infection/perforated viscera.

First-intention healing

Primary union: a clean incision with edges approximated (sutured); heals fastest with minimal scarring.

Second-intention healing

The wound is left open to heal by granulation from the bottom up (e.g., infected/contaminated wounds); more scarring.

Third-intention (delayed primary) healing

A contaminated wound is left open, then sutured/closed after several days once infection risk decreases.

Dehiscence vs evisceration

Dehiscence = partial or total separation of wound layers; evisceration = protrusion of viscera (e.g., bowel) through the open wound — an emergency.

Surgical site infection (SSI) prevention

Maintain sterile technique, give timely prophylactic antibiotics, normothermia, glucose control, proper hair removal (clippers), and skin antisepsis.

Dressing purposes

Protect the wound, absorb drainage, apply pressure/support, maintain a moist healing environment, and provide a barrier to contamination.

Steps after the procedure (closing)

Perform the final counts, hand off the specimen, account for sharps, apply the dressing after the drape is removed, and break down the field safely.

PACU (post-anesthesia care unit)

Where the patient recovers from anesthesia and is monitored (airway, vitals, level of consciousness) before discharge to a unit or home.

Breaking down the sterile field

After the dressing is on, keep gown/gloves until the patient leaves; dispose of sharps in puncture-proof containers and handle instruments to prevent injury.

OR turnover / terminal cleaning

Between cases, surfaces and equipment are cleaned/disinfected; terminal cleaning (end of day) is a thorough decontamination of the entire room.

Malignant hyperthermia (MH)

A life-threatening reaction to certain anesthetics (volatile agents, succinylcholine): rising end-tidal CO₂, rigidity, tachycardia, and later high fever; treat with dantrolene.

Dantrolene

The antidote for malignant hyperthermia; the CST/team helps reconstitute many vials rapidly while the agent is stopped and the patient is cooled.

Postoperative complications to monitor

Hemorrhage, shock, SSI, atelectasis/pneumonia, DVT/PE, urinary retention, ileus, dehiscence/evisceration, and nausea/vomiting.

Hypothermia prevention

Warm IV fluids/irrigation, forced-air warming blankets, and a warm OR; normothermia lowers SSI and bleeding risk.

Steri-Strips / skin closure tapes

Adhesive strips that approximate skin edges, used alone for small wounds or to reinforce a sutured/stapled incision.

Surgical site verification post-op

The dressing, drains, and specimen are documented; counts must be correct and recorded before the patient leaves the OR.

Decontamination

The first step of instrument processing: cleaning/disinfection to remove blood, debris, and microbes so an item is safe to handle before sterilization.

Spaulding classification: critical items

Items entering sterile tissue or the vascular system (surgical instruments, implants) — must be STERILIZED.

Spaulding: semicritical items

Items contacting mucous membranes or non-intact skin (endoscopes, laryngoscope blades) — require at least high-level disinfection.

Spaulding: noncritical items

Items contacting only intact skin (BP cuffs, OR table) — require low- or intermediate-level disinfection.

Sterilization vs disinfection

Sterilization destroys ALL microbial life including spores; disinfection destroys most pathogens but not necessarily all spores.

Steam (autoclave) sterilization

Moist heat under pressure (e.g., 250°F/121°C gravity or 270°F/132°C prevacuum) — the most common, economical method for heat/moisture-stable items.

Why clean before sterilizing?

Organic debris (blood/protein) shields microbes and prevents the sterilant from contacting all surfaces, so cleaning must precede sterilization.

Ethylene oxide (EO/EtO) sterilization

A low-temperature gas method for heat- and moisture-sensitive items; effective but toxic, flammable, and requires lengthy aeration.

Hydrogen peroxide gas plasma

A low-temperature method (e.g., Sterrad) for delicate/heat-sensitive items; fast aeration, no toxic residue, but lumen/cellulose limits.

Peracetic acid sterilization

A liquid chemical sterilant used for immersible heat-sensitive items like endoscopes; just-in-time, not for long storage.

Immediate-use steam sterilization (IUSS)

Formerly 'flash' sterilization for an item needed immediately; minimize its use — items are not packaged for storage and must be used at once.

Biological indicator (BI)

A vial of resistant bacterial spores (Geobacillus stearothermophilus for steam) processed and incubated to confirm the sterilizer actually killed spores.

Chemical indicator (CI)

A tape/strip/integrator that changes color to show an item was EXPOSED to the sterilant — but does NOT prove sterility (only the BI does).

Bowie-Dick test

A daily air-removal/steam-penetration test for prevacuum steam sterilizers, run in an empty chamber before the first load.

Mechanical indicators

The sterilizer's gauges/printouts of time, temperature, and pressure that verify the cycle ran within parameters.

Event-related sterility

A package stays sterile until an event compromises it (tear, wetness, drop) — not a fixed expiration date — given proper storage.

Inspecting a sterile package before use

Check the integrity (no tears/holes/moisture), the chemical indicator change, and the package seal before opening onto the field.

Loading the sterilizer

Open box locks/ratchets, place items so the sterilant contacts all surfaces, do not overload, and position basins/cups on edge to drain.

Peel pack orientation

Place the package paper-to-paper and plastic-to-plastic, and present so the steam/sterilant can enter — open toward the sterile field for delivery.

Lumen / cannulated instrument processing

Flush and brush lumens; some low-temp methods require lumen length/diameter limits or adapters so the sterilant reaches the inside.

Ultrasonic cleaner

Uses cavitation (sound-wave bubbles) to remove fine debris from box locks, serrations, and crevices after gross cleaning.

Instrument lubrication ('milk')

A water-soluble, steam-permeable lubricant applied to hinged instruments to maintain action and prevent stiffness/spotting.

Enzymatic cleaner

A detergent containing enzymes that break down blood, protein, and other organic soil during decontamination.

Workflow direction in sterile processing

Move from dirty (decontamination) to clean (prep/pack) to sterile (sterilizer/storage) — never backward — to prevent recontamination.

PPE in decontamination

Wear gloves, a fluid-resistant gown, a mask, and eye/face protection because of splash and bioburden when cleaning soiled instruments.

Wrapping for sterilization (double-wrap)

Sequential or simultaneous double wrapping (or a rigid container) maintains a sterile barrier and allows aseptic opening.

Storage of sterile supplies

Store in a clean, dry, low-traffic area; off the floor, away from vents/sprinklers, with controlled temperature and humidity.

Prion (CJD) instrument handling

Prions resist standard sterilization; use special extended protocols, single-use items when possible, or destruction per policy for suspected CJD.

Care of powered/pneumatic instruments

Do not immerse motors unless rated; clean, lubricate, and test drills/saws per manufacturer instructions for use (IFU).

Manufacturer IFU importance

Always follow the device manufacturer's instructions for use for cleaning, lubrication, and the validated sterilization method/parameters.

Anatomical position

The reference posture: standing erect, facing forward, arms at sides, palms forward — used to describe all directional terms.

Superior vs inferior

Superior = toward the head (upper); inferior = toward the feet (lower).

Anterior (ventral) vs posterior (dorsal)

Anterior = toward the front of the body; posterior = toward the back.

Medial vs lateral

Medial = toward the midline; lateral = away from the midline (toward the side).

Proximal vs distal

Proximal = closer to the trunk/point of attachment; distal = farther from it (e.g., the wrist is distal to the elbow).

Sagittal / coronal / transverse planes

Sagittal = divides left/right; coronal (frontal) = divides front/back; transverse (axial) = divides top/bottom.

Four abdominal quadrants

RUQ, LUQ, RLQ, LLQ — divided by lines through the umbilicus; locate organs (e.g., appendix in the RLQ).

Layers of the abdominal wall (incision order)

Skin → subcutaneous (Camper's/Scarpa's fascia) → muscle/fascia (rectus/external oblique) → transversalis fascia → preperitoneal fat → peritoneum.

Pericardium / pleura / peritoneum

Serous membranes lining cavities: pericardium (heart), pleura (lungs), peritoneum (abdominal cavity).

Layers of the GI tract wall

Mucosa → submucosa → muscularis (externa) → serosa (or adventitia) — from lumen outward.

Chambers of the heart

Right atrium, right ventricle, left atrium, left ventricle; the right side pumps to the lungs, the left side to the body.

Heart valves

Tricuspid (RA→RV), pulmonary (RV→lungs), mitral/bicuspid (LA→LV), aortic (LV→body) — keep blood flowing one way.

Coronary arteries

The right and left coronary arteries (LAD, circumflex branches) supply the heart muscle itself.

Path of blood through the lungs

RV → pulmonary artery → lungs (oxygenated) → pulmonary veins → left atrium (pulmonary circulation).

Layers of the GI: stomach to anus order

Esophagus → stomach → duodenum → jejunum → ileum → cecum → colon (ascending, transverse, descending, sigmoid) → rectum → anus.

Accessory digestive organs

Liver, gallbladder, and pancreas — produce/store bile and enzymes that aid digestion.

Biliary tree (gallbladder surgery anatomy)

Bile flows: liver → hepatic ducts → common hepatic duct; gallbladder → cystic duct → common bile duct → duodenum (via ampulla of Vater).

Calot's (cystohepatic) triangle

The landmark in cholecystectomy bounded by the cystic duct, common hepatic duct, and liver; the cystic artery runs within it.

Urinary system organs

Kidneys → ureters → bladder → urethra; the kidneys filter blood and form urine (nephron is the functional unit).

Layers of the meninges

Dura mater (outer), arachnoid (middle), pia mater (inner) cover the brain and spinal cord; CSF sits in the subarachnoid space.

Female reproductive anatomy

Ovaries → fallopian tubes → uterus → cervix → vagina; relevant to hysterectomy, salpingectomy, and oophorectomy.

Male reproductive anatomy

Testes → epididymis → vas deferens → seminal vesicles/prostate → urethra; relevant to vasectomy, prostatectomy, and orchiectomy.

Long bone structure

Diaphysis (shaft), epiphysis (ends), metaphysis, periosteum (outer membrane), and medullary cavity (marrow).

Bones of the forearm / lower leg

Forearm: radius (lateral, thumb side) and ulna (medial). Lower leg: tibia (shinbone) and fibula (lateral).

Eye anatomy (key layers)

Cornea, anterior chamber, iris/pupil, lens, vitreous, retina; relevant to cataract and retinal surgery.

Ear divisions

Outer (auricle, canal), middle (ossicles: malleus, incus, stapes; tympanic membrane), inner (cochlea, vestibule); relevant to myringotomy.

Respiratory tract structures

Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli (site of gas exchange).

Tissue types

Epithelial (covers/lines), connective (supports, e.g., bone/blood), muscle (contracts), and nervous (transmits impulses).

Homeostasis

The body's maintenance of a stable internal environment (temperature, pH, fluid/electrolyte balance) despite external changes.

Endocrine glands of surgical interest

Thyroid and parathyroids (neck), adrenal glands (atop kidneys), pituitary (brain), and pancreas (islets) — sites of common procedures.

Microorganism

A microscopic living organism — bacteria, viruses, fungi, protozoa, and prions are the groups relevant to surgical infection control.

Bacterial shapes

Cocci (spheres), bacilli (rods), and spirilla/spirochetes (spirals); arrangements include strepto- (chains) and staphylo- (clusters).

Gram-positive vs Gram-negative

Gram-positive bacteria stain purple (thick peptidoglycan wall); Gram-negative stain pink/red (thin wall + outer membrane). Guides antibiotics.

Staphylococcus aureus / MRSA

A Gram-positive cluster-forming cocci; a leading SSI cause. MRSA is methicillin-resistant and requires contact precautions.

Bacterial spores

Dormant, highly resistant forms (e.g., Clostridium, Bacillus) that survive heat/chemicals; sterilization must kill spores.

Clostridioides difficile / C. tetani

Spore-forming anaerobes: C. difficile causes colitis (needs soap-and-water hand washing); C. tetani causes tetanus.

Aerobic vs anaerobic bacteria

Aerobes require oxygen; anaerobes grow without it (and many are killed by oxygen) — affects culture method and antibiotic choice.

Pseudomonas aeruginosa

A Gram-negative aerobic rod, common in moist environments; an opportunistic SSI and burn-wound pathogen.

Pathogen vs normal flora

A pathogen causes disease; normal flora are resident microbes that are usually harmless but can cause infection if displaced (e.g., gut flora in the peritoneum).

Chain of infection

Agent → reservoir → portal of exit → mode of transmission → portal of entry → susceptible host; breaking any link prevents infection.

Modes of disease transmission

Contact (direct/indirect), droplet, airborne, vehicle (food/water/blood), and vector — guide isolation precautions.

Standard precautions

Treat all blood and body fluids as potentially infectious: hand hygiene, gloves, gowns, masks/eye protection, and safe sharps handling for every patient.

Bloodborne pathogens (HBV, HCV, HIV)

Viruses transmitted via blood/body fluids; the main occupational risk after a needlestick — follow exposure protocol and report immediately.

Most common SSI organisms

Staphylococcus aureus (incl. MRSA), coagulase-negative staph, Enterococcus, E. coli, and Pseudomonas.

Virus vs bacterium

A virus is an acellular particle that must replicate inside a host cell (not killed by antibiotics); a bacterium is a single-celled organism.

Fungi of surgical concern

Yeasts (Candida) and molds (Aspergillus) cause opportunistic infections, especially in immunocompromised patients.

Nosocomial (healthcare-associated) infection

An infection acquired in a healthcare setting (e.g., SSI, CAUTI, CLABSI, VAP) not present on admission.

Hand hygiene importance

The single most effective measure to prevent the spread of infection; use alcohol-based rub or soap-and-water (soap for spores like C. diff).

Resident vs transient flora

Resident flora live deep in skin layers (hard to remove); transient flora sit on the surface and are removed by handwashing/scrub.

Endogenous vs exogenous infection source

Endogenous = from the patient's own flora; exogenous = from an outside source (staff, instruments, environment).

Pharmacology: generic vs trade name

Generic = the official nonproprietary drug name (lowercase); trade/brand = the manufacturer's name (capitalized), e.g., epinephrine vs Adrenalin.

Routes of medication administration

Topical, oral (PO), IV, IM, subcutaneous, intrathecal, and on-field instillation/irrigation; the CST handles many drugs ON the sterile field.

Medication labeling on the sterile field

Label EVERY medication, container, and solution on the field immediately (even one), and verify the drug, strength, and expiration aloud with the circulator.

Local anesthetics (examples)

Lidocaine, bupivacaine (Marcaine), and procaine — block nerve conduction for local/regional anesthesia; lidocaine onset is fast, bupivacaine lasts longer.

Why add epinephrine to a local anesthetic?

Epinephrine causes vasoconstriction, which prolongs the anesthetic's action and reduces bleeding — but avoid in end-arteries (fingers, toes, nose, penis).

General vs regional vs local anesthesia

General = unconscious, whole-body; regional = a region numbed (spinal, epidural, block) with the patient awake; local = a small area numbed.

Anesthetic agent classes (general)

Inhalation agents (sevoflurane, desflurane, nitrous oxide) and IV agents (propofol, ketamine, etomidate); muscle relaxants paralyze for intubation.

Neuromuscular blockers

Depolarizing (succinylcholine — fast, short) and non-depolarizing (rocuronium, vecuronium) relax muscles; succinylcholine can trigger MH.

Common surgical irrigation fluids

Normal saline (0.9% NaCl) and sterile water; warmed for normothermia. Choice depends on the tissue (e.g., not water near open vessels due to hemolysis).

Heparin (intraoperative use)

An anticoagulant used on the field (e.g., vascular cases) to prevent clotting; its reversal agent is protamine sulfate.

Protamine sulfate

The reversal agent for heparin; given to neutralize anticoagulation (e.g., after vascular/cardiac procedures).

Thrombin (topical)

A topical hemostatic agent applied to a bleeding surface to promote clotting; never inject it intravascularly.

Contrast media

Radiopaque dyes (e.g., for cholangiography) injected to visualize ducts/vessels on fluoroscopy; ask about iodine/shellfish allergy.

Surgical dyes/stains

Methylene blue, gentian violet, and indigo carmine — mark tissue/margins or identify structures (e.g., methylene blue for leaks).

Antibiotic irrigation/prophylaxis

Prophylactic antibiotics (often a cephalosporin like cefazolin) are given before incision; antibiotic irrigation may be used on the field per surgeon.

Drug measurement / dosage basics

Use the metric system: 1 g = 1,000 mg, 1 mg = 1,000 mcg, 1 L = 1,000 mL; percent solution = g of drug per 100 mL.

Reading a 1% lidocaine concentration

1% = 1 g per 100 mL = 10 mg/mL; so a 10 mL vial of 1% lidocaine contains 100 mg.

Six rights of medication

Right patient, right drug, right dose, right route, right time, and right documentation — confirmed when handling drugs on the field.

Controlled substances

Drugs with abuse potential (e.g., opioids) are scheduled (C-II to C-V), tracked, counted, and witnessed for waste per DEA/facility policy.

Drug allergy verification

Confirm allergies (latex, iodine, medications) before prep/anesthesia; communicate them to the team and document.

AST role vs NBSTSA role

AST (Association of Surgical Technologists) is the professional association; NBSTSA (National Board of Surgical Technology and Surgical Assisting) develops and awards the CST credential.

CST eligibility

Graduation from a surgical technology program accredited by CAAHEP or ABHES qualifies a candidate to sit for the CST exam.

CST recertification

Maintain the CST by earning continuing education credits over a multi-year cycle (commonly 60 CE credits over 4 years) or by re-examination.

Informed consent responsibility

The surgeon (provider) is responsible for obtaining informed consent; the team verifies it is signed, complete, and matches the planned procedure/site.

Chain of command

Report concerns through the proper line (charge nurse, supervisor, manager); the CST escalates patient-safety or sterility issues appropriately.

Scope of practice (CST)

Practice within the legally and facility-defined CST role; do not perform tasks outside training/credentialing (e.g., independent prescribing or surgeon-only acts).

Documentation accuracy

Counts, implants (with lot/serial), specimens, medications, and equipment used must be documented accurately and legibly in the operative record.

HIPAA / patient confidentiality

Protect patient health information; discuss cases only with the care team and only as needed for care.

OR attire / restricted areas

Wear clean surgical attire, cover all hair, and don a mask in restricted areas; traffic and door openings increase contamination risk.

Preference card

A surgeon-specific record of preferred instruments, supplies, sutures, gloves, and setup for a given procedure — used to pull the case.

Implant handling and documentation

Verify size/type, keep implants sterile, and record the manufacturer, lot/serial number, and expiration in the operative record for traceability.

OSHA in the OR

Sets workplace safety standards (bloodborne pathogens, hazard communication, sharps safety, surgical smoke) to protect staff.

Fire triangle in the OR

Fuel (drapes, alcohol prep, hair), oxygen (O₂-enriched field), and ignition (ESU, laser) — control all three to prevent OR fires.

Latex allergy precautions

Use latex-free gloves and supplies, schedule the case first (lowest airborne latex), and post signage to prevent anaphylaxis.

Inventory and supply management

Maintain par levels, rotate stock by expiration (FIFO), and restock case carts so supplies are available and unexpired.

Aseptic technique vs sterile technique

Aseptic technique = practices that reduce contamination broadly; sterile technique = the strict practices that keep a defined field free of all microbes.

Opening sterile supplies

Open the far flap first, then the sides, then the near flap toward yourself; never reach over the sterile field or turn your back to it.

Pouring solution onto the sterile field

The circulator pours from the edge into a basin held by the scrub (or at the field's edge) without splashing or reaching over the field.

Once sterile setup is open, keep it sterile

Keep sterile setups continuously monitored; an unattended or covered field is considered contaminated.

Draping the patient

Apply drapes from the incision site outward; once placed, do not move drapes toward the field — only away — and never reposition a dropped drape.

Vital signs (normal adult ranges)

HR ~60–100/min, RR ~12–20/min, BP ~120/80 mmHg, temp ~98.6°F/37°C, SpO₂ at least 95% — baseline patient monitoring values.

Capnography (EtCO₂)

Continuous end-tidal CO₂ monitoring confirms ventilation and tube placement; a sharp rise is an early sign of malignant hyperthermia.

Pulse oximetry (SpO₂)

A noninvasive measure of arterial oxygen saturation; normal is at least 95%; falling values signal hypoxemia.

Shock (perfusion failure)

Inadequate tissue perfusion; types include hypovolemic (blood/fluid loss), cardiogenic, distributive (septic/anaphylactic), and obstructive.

Signs of intraoperative hemorrhage

Rising heart rate, falling blood pressure, increasing blood in suction/sponges, and a tense/expanding field — alert the surgeon and prepare hemostatic supplies.

Anaphylaxis intraoperatively

A severe allergic reaction (latex, drugs, contrast): hypotension, bronchospasm, hives, and edema; treated with epinephrine — keep it available.

DVT prophylaxis in surgery

Sequential compression devices, early mobilization, and anticoagulants reduce deep vein thrombosis and pulmonary embolism risk.

Foley catheter purpose

An indwelling urinary catheter drains and measures urine during long procedures; inserted with sterile technique to prevent CAUTI.

Nasogastric (NG) tube

A tube from nose to stomach to decompress the GI tract or remove contents; used in many abdominal procedures.

ESU return-pad alarm

If the electrosurgical unit alarms or won't activate, check the dispersive pad contact and connections before increasing power, to avoid burns.