2Asepsis DefinitionsPathogenic = the ability to cause disease in a living organismAsepsis = the maintenance of a pathogen-free environment; the reduction of micro-organisms to a level that will not cause infectionSterilization = the destruction or elimination of all living micro-organisms and their sporesDisinfection = the destruction of pathogenic microorganisms on an object to a harmless levelSome disinfectants are not effective against spores
3DefinitionsAntiseptic = destroys pathogenic organisms on living tissueSanitation = the reduction of the number of organisms on an object to an acceptable health standard; also refers to rendering an object aesthetically pleasing and cleanSuffixes“—cidal” has a killing action“—static” inhibits growthWe tend to say “disinfectant” more though than antiseptic… i.e. “skin disinfectant”
4Animal prep Prep/scrub of surgical site(s) - Surgical site(s) must be prepared by closely clipping and removing the hairThis should be done in an area separate from where the surgical procedures are to be performedAvoid skin abrasions and thermal injuries during clipping and avoid clipping excess hair as this may exacerbate hypothermiaThe animal’s skin the “weak link” in aseptic technique. The incision site cannot be "sterilized“ per se without possibly damaging tissue.Proper preparation can minimize contamination of the surgical field with skin microorganisms.
5Animal prep Preparation of the site should include Use of an appropriate skin disinfectant applied in three cycles of scrubbing with a surgical soap (Chlorhexidine, Iodophore)Rinsing with sterile water or 70% isopropyl alcohol between each scrub with soapUsing sterile cotton swabs or gauze, disinfection should begin along the incision line and extend outward in a circular pattern(e.g.:Hibiclens® , Betadine® Scrub)You should do the final scrub within the OR, and a final spray or paint with Iodine or other disinfectant sol’n is done prior to draping.Note: if you have a ‘prolonged’ period of time betwn scrub and final spray/paint – place a sterile towel over the site – it will remove excess sol’n and keep site sterile
6Animal prep Draping of animal/surrounding area The use of a sterile drape over the animal is used to prevent contamination of suture material and to assure a sterile field at the surgical sitePaper drapes are convenient because you can customize the hole to fit the surgical site.Disposable surgical drape material is resistant to tearing when wet, and the blue/green color helps reduce glare from surgery lights.Rodent surgeons often use “Steri-Drapes” to drape an entire animal – helping with observation of breathing/color; Large Animal surgeons use them help hold larger paper drapes in place and just incise through them when making initial skin incision.A common mistake is to make the drape too small. The larger the sterile field you create, the easier you will find it to avoid "breaks" in sterile technique.
7Surgeon Prep - Scrubbing After donning scrubs, mask & capWash hands for 30-60secScrub hands and fingersWash and then scrub forearmsRinse and repeatDry with sterile towelbeginning with fingers and moving towards the forearms, use new towel for each handTotal scrub time should be around 5 minutesWash Hands – just removing the ‘big stuff’ here…Scrub hands and fingers -- getting all surfaces for minimum 10 strokes each surfaceMove down and wash forearms ~60sec, then scrub all surfaces of the forearm with the same 10 strokes per planeRinse from fingers to elbows in the “praying mantis” pose“posture” = hands stay upward at all times, NEVER below your waste!Some surgeons do not rinse off the final chlorhexidine in order to enhance residual activity
8Surgeon Prep - GowningGrasp the exposed inside surface and lift the gown away from the tableUnfold the gown by placing hands into the arm holesContinue placing hands and arms through the sleevesAn assistant fastens the neck and the inside waist tiesProceed with gloving before the fastening of the final outside tieAll gowns are packed with the inside exposed so that the surgeon may handle the gown without contaminating the outside of the gown.If you are planning on closed gloving, do not thrust your hands through the cuffs“posture” – again your hands stay close in and above your waist!
9Surgeon prepGlovingClosed gloving is performed after the surgeon has donned his/her gown, but BEFORE the surgeon pushes his/her hands through the cuffs of the gown; gloves are pulled on as the hands are pushed through cuffOpen gloving is also done after donning the gown, but the hands are pushed completely through the cuffsClosed gloving might be considered “more sterile” as it allows no room for skin to glove contact, as can occur with open gloving
10Surgical AreaTraffic - access to persons not directly involved in the activities should be limited during the surgical procedureDesignated support areas ideally should include components such as animal prep, surgeon scrub, holding and recovery areas outside of the ORDesignated areas are “must” for USDA non –rodent species
11Surgical AreaOR - the area in which surgery is conducted should be free of clutter and disinfected prior to beginning the surgical session.This area should be located away from air supply ducts or other drafts to minimize hypothermia of the animal and limit accumulation of dirt and dust contamination on surfaces
12Creative Draping/Sterilization Draping accessory and support equipment (e.g. lights, microscopes, monitoring equipment/leads, anesthesia machine, cautery equipment, etc.) can allow the surgeon to maintain a sterile field if adjustments to equipment are needed during the procedurePaper drapes, sticky drapes, sterilized plastic bags work well, depending on the equipment,You can use sterile stockingnette to cover equipment such as Stryker saws if you don’t have a way to gas sterilizeYou can use liquid disinfectants also to wipe equipment down – make sure you allow for enough contact & dry time ! Also make sure if you use this method that the equipment does not come into direct contact with tissues unless you can ‘rinse’ or wipe down with sterile saline.
13Sterilization types/methods AutoclaveMoist heatEffectiveness dependent upon temperature, pressure, and time (normal is 121◦C / 15psi / 15min)Indicators range from exterior color changes on packages, to interior and load indicators for the specific type of autoclaveIonizing RadiationGamma RadiationRequires special equipment and trainingNote - the expiration date on the packThe shelf life of a sterile package will depend on the quality of packing, conditions during storage and transport, and the amount of handling prior to use.Basic rules of thumb re: storage are:the shelf life of double wrapped instruments is generally considered to be up to 6 monthsWrapping the pack in plastic will extend the shelf life to one yearDate and rotate the supplies (first in, first out)Packs will remain sterile as long as the integrity of the package is maintained.Human hospitals have gone to a rule of “The shelf life of a packaged sterile item is event-related and not time related”.Events that can compromise or destroy package sterility include multiple handling, loss of package integrity, moisture penetration andairborne contamination.Biological sterilization indicators for autoclaves contain spores that are supplied in closed containers and are included with the instrument being autoclaved. Inability to culture the spores after autoclaving confirms adequate sterilization. Biological indicators are the most accurate sterilization indicators
14Sterilization types/methods GasEthylene oxide, Plasma VaporETO requires 30% or greater relative humidity for effectiveness against spores and requires safe aeration timePlasma vapor can not be used on cellulose-based or absorbable materialsBoth gasses are good for heat/moisture sensitive instruments/devicesSpecialized pouches have color indicators, also need load and interior pack indicatorsColdGluteraldehyde, ClidoxAll materials must be rinsed in sterile salineMost are corrosive to instruments and require prolonged contact timesEtO and Plasma vapor have both been mentioned to possibly affect catheter materials (e.g.: less flexible, more rigid)Note package indicators or tapes attached prior to sterilization only indicate that the package has been exposed to the vapor; they do not monitor sterilizer functionGluteraldehyde has 6 hr contact time. EtO needs hrs to air out.
15Sterilization types/methods Flashing and Bead sterilizers“flashing” in the autoclave = normal is 131◦C / 30psi / 3 min; instruments must be placed in special metal containers with aeration holes“flashing” via open flame = not recommended as it is hard to regulate the temp and time, often resulting in warped, permanently damaged tips on fine instrumentsBead sterilizer = ~15 seconds/instrument'Flashing' is when an instrument is autoclaved for a shorter period of time. 'Flashing' is often used when a critical instrument is dropped.This method is intended to allow use of the instrument “immediately” – they should not be stored for later use.Use of the bead sterilizer is done mostly in Rodent batch surgeries…. Where you start sterile pack and then use the bead unit between animals.If you’re ‘flaming’ or using bead unit – make sure cool in sterile saline!
16Instruments Handling /cleaning/care basics Lubricant – also called “instrument milk” for all instruments with metal on metal moving partsScissors, hemostats, needle drivers, self- retaining retractors, etc.Do NOT use WD-40 or motor oil !!Ultrasonic Cleaner – best way to clean any instrument, but especially good for hinges and any instrument with teeth or groovesMake sure you’re using neutral pH detergent and cleaners…. Or you’ll cause staining and or pitting and erosion problems.
17Handling / cleaning/care basics Packing and wrappingDisposable pouches – Great for single instruments, make sure they’re wide enough to accommodate the instrument in an unlocked/open positionTrays – use towels or other absorbent layer in the bottom if autoclaving to prevent “wet packs”Never lock an instrument during autoclaving!Steam will not penetrate all areas (true for gas sterilization too)Will develop cracks in hinges because of heat expansion during cycles
18Handling / cleaning/care basics Staining with use -Brown/orange = phosphate deposits (from dirty autoclave water source, high alkaline soaps) or bloodA pencil eraser will remove these, but not true rustBlack stains = acidic detergent residue during autoclave/high heat processingAlways rinse with DI water before sterilizationRainbow stains = excessive heat, may have lost metal integrityUse heat source that has set ranges/know temps (e.g.: Germinator)“Out of the box” Stained -Sometimes carbon steel instruments come with an oily coating on them from the manufacturer, this is normal and helps prevent corrosion – it’s just mineral oil; this should be cleaned off prior to initial sterilizationRust is seen in the cheaper alloys and has to be removed by physical ‘grinding’ of the surface – if you ‘re using ‘cheaper’ instruments – you may want to stick with lesser abrasive sterilization techniques (e.g.: probably not going to do well in a 6hr soak in Gluteraldehyde)Carbon Steel will develop it’s own protective coating – kind of like “seasoning” a cast iron skillet… but the oil makes sure it looks pretty when you uppack it !
19Material selection Carbon Steel – is the hardest of materials Tips may become brittle with excessive heatHighly magnetic and stains easilyStainless Steel – an alloy (mix of metals)many different types and gradesVarying levels of stain resistance and magnetismCan still rust, corrode and pitTitanium – lightest of the alloys usedExtremely corrosion, heat and stain resistantCompletely non-magneticCeramic – offered mostly as a coatingVery hard, scratch resistance, no reflection for work under microscopeAnti-corrosive, biocompatible
20Instrument SelectionUse and user preference may dictate tip shape and angle, overall weight, and handle length and typeSurgeon preferenceHand sizeHeightTissue to be manipulatedBone, brain, muscle, skin, etcPosition / location of tissueDepth, surrounding structures
21Instrument Selection Why different tips? Smooth, Teeth or grooves? Tissue retention holes, catheter holding grooves, vessel dilation?Depends on what you need to do, what organ you’re handling and what approach you’re usingSmooth doesn’t always mean atraumatic! Again, it depends on what you’re doing and handling – if you’re using smooth fine tipped forceps to hold onto rat skin, you’re going to have to squeeze much harder to keep a hold of it than if you used 1x2 rat toothed forceps!Which way the grooves run also impacts the effect, generally speaking if they run longitudinal they’re going to allow ‘flow’, if they run horizontal, they’ll prevent flow.Up on the screen we’ve goton top: tissue retention holes – made for ophthalmic use and holding very fine tissues w/o ripping like teeth mightmiddle: catheter holding grooves – made for just what it sounds like bottom: these tips slide inside a vessel to open it up the lumen – however they don’t do as well grasping
22Instrument SelectionFurther illustration of why one would choose a particular pattern – hemostats that either allow flow, or provide complete hemostatis
23Instrument Selection Straight vs. curved vs. angled? Ok, these are tips from some micro-vanna scissors…. The top are straight, the middle curved and the bottom angled to the right…Depending on what and where you’re cutting, will determine your choice.
24Instrument Selection Colors or Plating on handles Can color code by type of pack, by PI, etc.Black plated rings typically mean a razor edge on one blade and serrated blade on the otherEasier to cut soft tissues without crushing, making for clean smooth-edged cutsGold plated rings indicate tungsten carbide insertsIn scissors this is preferred for use when cutting thick skin or cartilage
25Types / categories / uses: Forceps / Clamps / HemostatsNeedle Holders (Drivers)RetractorsScissors / ScalpelsElectrocautery“Other”In the most general of terms : forceps, clamps and hemostats are somewhat “interchangeable” in that they all can be used to ‘hold or grasp’ and or stop flowForcepsSoft Tissue Forceps. Similar to hemostats, these forceps are used for holding and retracting soft tissue for longer periods. Characteristics include fine teeth or ridges on the jaws to provide a more delicate grip without trauma to tissue. They also consist of ring handles and box locks, as do the hemostatic forceps.Other Soft Tissue Forceps (Thumb). Thumb forceps do not have box locks or ring handles but rather have spring handles which are held closed by the thumb and finger pressure. Sometimes this type of forceps is referred to as dressing forceps when the jaws are serrated and the instrument is used to grasp delicate tissue or wound dressing. A heavier version of this type of forceps is referred to as thumb tissue forceps used for grasping heavier tissue where the teeth will provide a more secure grasp.Clamps - for stopping flow to a particular organ of interest in an atraumatic mannerHemostatic Forceps. These forceps can be called clamps, artery forceps, and hemostats. The main purpose of hemostats is to achieve hemostatis (control of blood flow in the vessel). Most hemostats are available in different lengths, curved and straight, with serrated jaws. Some also have toothed ends.Like many instruments, forceps, clamps and hemostats often bear the name of their design originator, such as Adson tissue forceps , and the Kelly, Halstead and Crile hemostats.Needle Holders are pretty self-explanatory … vets tend to call them holders, human docs tend to call them drivers. What separates them is the type of tying platform they have and the addition of cutting blades to some. similar to hemostats but with smaller jaws which are shorter and thickerRetractors – again, pretty self explanatory – they hold tissue out of your way – be it by hand held or fixed via screws, locking jaws or spring actionElectrocautery – sometimes people forget about this as an instrument – but think about it – you can cut, or you can provide hemostasis with the right tip, and they come in lots of styles
26Forceps Adson tissue forceps Adson- Brown tissue forceps Rat toothed forcepsDressing forcepsDumontsThe Adsons tissue forceps is a standard thumb-operated, wishbone type forceps for grasping tissue - has delicate serrated tips designed for light, careful handling of tissue; it may or may not also have a 1x2 tooth configuration at the tipThe Adson–Brown tissue forceps have multiple fine teeth at the edges of the tips. These teeth run longitudinally/down the side vs. across the tipRat Tooths Interdigitating teeth hold tissue without slipping ; Used to hold skin/dense tissueDressing forceps have a wide, blunt tip and wider, courser rounded serrations across each tipDumonts are typically used in fine micro-vascular surgeries
27Needle Drivers Olsen-Hegar Castroviejo Mayo-Hegar Mayo-Hegar Heavy, with mildly tapered jaws. No cutting blades.Olsen-Hegar- Includes both needle holding jaw and scissors blades. The disadvantage to having blades within the needle holder is the suture material may be accidentally cutCastroviejo – has a spring action w/ locking mechanism, this lock secures the needle and is often used in surgical procedures requiring delicate suturing in tight or poorly exposed areas.
28Clamps Satinsky clamp DeBakey clamp Cooley clamp Bulldog clamps Satinsky are a vascular clamp with horizontal serrations across length of their jawsCooley’s are also vascular clamp and normally you see them with calibration marks on the outside of the jawdeBakey’s - another vascular clamp designed specifically to grasp vascular tissue with minimal damage to the vessel – they have smooth longitudinal groovesOne of the most common applications where a bulldog clamp can be used is during coronary surgery where blood flow must be stopped. In general the bulldog clamp, with its many angled varieties and surgical applications, is an essential tool during surgery where blood flow to an organ must be stopped or controlled and the tool needs to be less obtrusive than a ring handled instrument.(FYI – I mentioned instruments being named after people….DeBakey and Cooley worked together on the first artificial heart transplantation in the late 60’s at Baylor)
29Bone Bone curette Rongeurs Trochar Periosteal Elevator Osteotome rongeur is a forcep used to cut or remove small pieces of bone and tissueOsteotome - a chisel-like instrument, often used with a mallet to cut or sculpt bone,curette is spoon-shaped instrument used to scrape, shape and remove boneTrochar is a sharp-pointed instrument fitted with a stylet, usually with a triangular point, used for exploring tissues or for inserting drainage tubesin small animal/rodent surgeries large bore biopsy needles are often used as “trochars” to tunnel catheters SCAn elevator is an instrument used for lifting or retaining at a greater height; sharp versions are used to strip the periosteum – the connective tissue covering the external surface of a bone
30Allis tissue forceps Alligator forceps Duval forceps Babcock forceps Vulsellum forcepsAlligator forcepsBabcock forcepsAllis: An Intestinal Tissue Forceps - Interdigitating short teeth to grasp and hold bowel or tissue. Slightly traumatic, used to hold intestine, fascia and skinDuval forceps are often used for grasping lung tissue in an atraumatic manner, the tips are designed to spread the pressure of traction in such a way as to reduce tearing that finer tips would incurVulsellum Long, scissor type forceps with ratchet handles and long, thin, sideways curved blades that have inward facing, double-pointed claws. Designed for grasping the tissue such as the uterus.Alligators are normally long forceps with a small hinged jaw on the end that allow for grasping in tight, hard to approach areas.Babcock: An Intestinal Tissue Forceps - More delicate that Allis, less directly traumatic. Broad, flared ends with smooth tips. Used to atraumatically hold viscera (bowel and bladder).
31Retractors Wilson rib spreader Army-Navy retractor Gelpi retractor WeitlanerArmy-Navy retractorGelpi retractorWeitlaner - Ends can be blunt or sharp. Has rake tips. Ratchet to hold tissue apart.Wilson rib spreaders are an example of a fixed retractor using a ‘wench’ type configuration – they have blunt, wide blades, used in cardiac approaches between the ribsGelpi- Has single point tips. Ratchet to hold tissue apartThe Army-Navy is a hand held retractor with blunt smooth blades for pulling
32Retractors Finochietto retractor Balfour retractor Senn retractor Senn Retractors are another hand held, and have blades at each end. Blades can be blunt (delicate) or sharp (more traumatic, used for fascia).The Finochietto is a bit more heavy duty than the Wilson, the blades are deeper and often come in configurations where the blade plates can be interchanged, cardiac approaches where the sternum is splitBalfour retractors are also often used abdominally, and offer three point retraction
33Scissors Iris scissors Lister bandage scissor Mayo scissors Metzenbaum scissorsAll types of scissors can have either straight or curved blades. All can have blunt or sharp blades (Sharp:Sharp, Blunt:Blunt).Mayo scissors are used for cutting heavy fascia and sutures. Metzenbaum scissors are more delicate than Mayo scissors.Metzenbaum scissors are used to cut delicate tissues. Metzenbaum scissors have a longer handle to blade ratio than Mayo’s.Iris (dissecting) scissors, resembling cuticle scissors but more delicate in style.Listers are easily ID’d by the piece at the end that allows one to slip them under the bandage and not accidentally cut the skin because it acts like a gaurd
34Scissors Strabismus Ragnell Doyen Micro-Vannas Strabismus are made for fine blunt dissectionRagnell scissors are also meant for fine blunt dissection – you can see the flattened blade tips that allow for more control within the tissue planesMicro-vannas are generally usd in micro – surgery to transect vessels to allow for cannulation with catheters or probe tipsDoyens are another type of bandage scissor – they have serrated blades
35Scalpels & Blades Handles come in #3 or #4 sizes Blades 11,12, 15 & 10 fit #3 handleBlades 22 and 23 fit #4 handleBlades #22, #23 fit the #4 handle and are commonly used for large animals
36Forceps Kelly forceps Mosquito hemostats Crile forceps Mosquito hemostats are more delicate than Kelly hemostatic forceps ; Both are transversely serrated ; Mosquitos have a smaller, finer tipCriles are very similar to Kelly’s with the exception that the transverse serrations stop approximately half way down on a Kelly; both the Mosquitos and Criles have serrations the entire length of the tip.
37Hemostats Rochester- Peans hemostat Rochester-Carmalt hemostat These are heavier duty clamps than the two we just looked at….Rochester- Carmalts are often preferred for clamping of ovarian pedicals or similar surgeries because the serrations run longitudinally and their heavier weight lend themselves to such applications, their striations run longitudinally.Rochester - Peans are much the same, a heavier clamp, with the striations running horizontal this time
38“Other” Stereotaxic gear Bovie Human hands! The stereotactic apparatus uses a set of three coordinates (x, y and z) to rpvide a 3-D framework of reference: angle, depth and antero-posterior location. The mechanical device has head-holding clamps and bars which puts the head in a fixed position in reference to the coordinate system (the so-called zero or origin).Electrocauterization is the process of destroying tissue using heat conduction from a metal probe heated by electric current (much like arc welding). The procedure is used to stop bleeding from small vessels (larger vessels being ligated) or for cutting through soft tissue. “Bovie” is a manufactureHands – be careful – you’d think we’re the most atraumatic instrument out there – but you can accidentally twist bowels or rest your hand too much and cut of blood supply….
39“Batch” Rodent Surgery / ‘tricks’ Start with a sterile packSterilize between uses =“resetting the stage”