Clinical Skills Assessment Flashcards
What is the critical level of contamination?
10^5 organisms per gram of tissue or an immune compromised patient
* there is no such thing as sterile surgery
What is sepsis? Asepsis? Antisepsis? Antiseptic? Disinfectant? Sterilisation?
What is aseptic technique?
Set of protocols and practices followed by all staff within the OR to reduce or eliminate the potential of contamination of surgical or traumatic wounds by pathogens. Applies to scrubbing, gowning, gloving, skin preparation of the patient, theatre etiquette and standard precautions when handling surgical patients.
What are the sources of contamination?
* The patient, surgical equipment and implanted materials (sutures, plates, screws, etc.), surgical personnel, the operating theatre environment
What are the non sterile barriers?
* Scrub suits, surgical head covers, face masks, shoes and shoe covers
What are the sterile barriers?
Gloves, gowns, drapes
* Material should be resistant to penetration by blood, fluids, low-linting, durable and resistant to puncture or tears
Why isn’t alcohol used stand alone? What is optimal?
Lacks residual action required for surgical procedures because it evaporates at room temperature
* Preoperative preparation of the patient’s skin with Chlorhexidine-Alcohol is superior to preparation with Povidone-Iodine for preventing surgical-site infection after clean-contaminated surgery
Why can’t you use Chlorhexidine and Povodone-iodine in combination?
Because of the cationic nature of Chlorhexidine and the anionic nature of Povidone, thus providing limited or no skin antisepsis
What are general safety recommendations with skin preparation?
* Alcohol based skin preparation must be allowed to evaporate thoroughly before utilizing diathermy devices
* Alcoholic solutions should not be allowed to pool under the patient
* Avoid overzealous washing or scrubbing techniques as this may cause skin irritation and release organisms that reside in the deeper layers of the dermis thus increasing the microorganisms present on the skin surface
* For MM and vaginal preps, a 10% (1% available iodine) Povidone- Iodine solution (not surgical hand scrub) should be used instead of chlorhexidine
* A 1 in 10 solution of 1% Povidone-Iodine aqueous solution is recommended for ophthalmic preps
Principles of hair removal
* Animal hair may harbor contaminants and hinder the skin cleaning process
* Shaving is not recommended due to propensity for nicks and cuts which has been shown to increase the post-operative infection rate up to ten-fold
* Clipping with a size 40 clipper blade is recommended, removing hair liberally around the proposed incision site with wide margins in all directions
* To reduce strain and heat generation from the clipper blades, clip with the grain of hair first, then against the grain
What are the three main steps to surgical skin preparation?
(bathed pre-operatively with 4% Chlorhexidine scrube solution)
- Pre-wash removal of all gross (visual) contamination with detergent based antiseptic
- Removal of the detergent
- Application of an approved surgical skin antiseptic product. Usually Povidone-iodine tincture or Chlorhexidine Tincture.
What is the full method of surgical skin preparation?
What is the aim of the surgical scrub?
* Remove dirt, flaking skin, oil and microorganisms from the hand, lower arms, as well as reducing the microbial count (residential and transient) to as close to zero as possible. To provide a prolonged inhibitory effect on the resident micro flora.
Ideal characteristics of a scrub antiseptic
* Must be broad spectrum and have the ability to reduce growth of transient and resident microorganisms. Rapid and cumulative action. Not create skin irritation. Residual/persistent action. Recognized TGA (therapeutic goods administration) hospital approved solution.
What is alcohol effective against?
* Alcohol is the most efficient broad spectrum antibacterial (including Methicillin Resistant Staph Aureus) and Vancomycin resistant Enterococci (VRE), antifungal and antiviral action
* Most effective when diluted to 70% to effectively denature proteins
* Slight residual action but they evaporate rapidly and are thus rendered ineffective
* Alcohol in combination with 0.5-1% Chlorhexidine (CHG) hand rub has been introduced into the market to create an effective alternative to the traditional water based surgical scrub
* When using Alcohol/ Chlorhexidine hand rub is must always be preceded by a general hand wash!!
What is the most widely used surgical hand scrub? What is the spectrum of activity?
4% Chlorhexidine Gluconate (CHG)
* Broad spectrum of activity against gram- positive and to a lesser extent gram-negative bacteria
* Provides minimal action against some viruses but is not sporicidal
* Acts by altering the cell wall and precipitates intracellular contents
* Immediate anti- bacterial action with ongoing residual action up to 6 hours by binding to keratin
* Active in the presence of organic material
* Contraindicated for use in the eyes and middle ear
Spectrum of activity of povidone-iodine?
Idohors have a broad spectrum of activity against bacteria, fungicidal, virucidal and may be sporicidal with prolonged contact.
** Works by slow release of active iodine
* Unlike Chlorhexidine it has low residual activity and is inactivated by organic material
What do you need to do pre-hand scrub?
Remove rings, bracelets and watches
* Fingernails must be clean, cut short and free of artificial nails and nail polish
* must be able to contact all aspects of the hands and arms… chipped nail polish and artificial nails reduce access of the antiseptic
How long should you hand scrub? Where do you start and finish?
* no less than 3 minutes
* start at the finger tips, moving towards the elbows, without back tracking
* hands are dried with a sterile towel then a sterile gown is donned
Alcohol hand rub considerations?
* Must be applied to clean, dry hands
* for the first scrub of the day clean under nails with a nail pick, then dispense pump (2ml) of hand prep into either hand and apply to all aspects of both hands up the wrists
* A second pump can be applied to cover both arms
* Allow the hands and arms to air dry then don the sterile gown
What is the sterile zone of a gown?
Mid chest level to waist level (in line with the operating table) and from elbows to cuffs– only the hands should touch these areas of the gown
** the aim is to don the gown without touching the sterile outside layer
What are the three methods for donning sterile gloves?
* Closed gloving (preferred and safest method to prevent contamination)
* Open gloving
* Assisted gloving
What is a standard draping procedure?
4 utility drapes and a large cover drape
* Utility drapes are placed in the near, top, tail, and far sequence… followed by the large cover drape (which may or may not have a fenestration)
What is free draping?
* orthopaedic procedures– paw is clipped and enclosed into a non-sterile glove, the limb is suspended upwards utilizing a pulley rope or drip stand
* Skin prep– then 3 utility drapes are placed around the base of the limb to isolate it from the trunk
* Distal paw is then isolated by wrapping sterilized Vetrap around the enclosed paw (or sterile stockinette)– then a water resistant barrier (e.g. sterile glove or waterproof drape) placed over the vetrap to prevent strike through contamination should the paw become wet— then typically more vetrap
Why should you reduce the number of people in the operating theatre?
Direct correlation between the number of people, their movements and the number of airborne bacteria in the operating theatre
What is important with ventilation systems and air flow?
* Ventilation systems should provide slight positive pressure compared to adjoining rooms and coordiors
* 15 changes per hour of filtered air
* Recommended temperature is 20C-23C with a relative humidity of 30-60%
How should the theatre be cleaned?
After the last surgical procedure of the day, wet vacuum or mop the floor using a hospital grade TGA approved detergent/disinfectant
* before the first surgical case of the day, all equipment, furniture and surfaces should be damp dusted using a lint free cloth moistened in a TGA approved detergent/disinfectant solution
* Use a separate lint free cloth to dry all surfaces
** NEVER dry dust, mop or vacuum in the operating theatre becuase it raises dust, hair and dander that may contain microorganisms
What are the sterilising guidelines for Vet practice?
AS4187- 2003, Cleaning, disinfecting and sterilising reusable medical and surgical instruments and equipment and maintenance of associated environments in health care facilities
** 1.1 Scope of the document “The standard may be suitable for application to the instruments and equipment used exclusively on animals in veterinary practice”
What is the ideal environment for instrument processing?
A dedicated room
* work flow that encourages separate processing, starting from cleaning contaminated goods, instrument inspection, instrument packaging, sterilising then storage without cross-over traffic…. ideally separate entry and exit
What is spaulding’s risk classification?
How should flexible endoscopes be sterilised?
Semi-critical but they are heat sensitive so they cannot withstand the high temps of steam sterilization
* High level disinfection such as OPA Cidex
What are ultrasonic cleaners?
Mechanical method with a low foaming, low alkaline detergent
* Cannot clean plastics or rubber because they absorb vibrations and prevent the oscillation process
Why do you dry instruments?
* Dried within a drying cabinet or manually dried with a lint free cloth
* Residual mositure would interfere with the creation of dry saturated steam and instead create wet steam– wet steam is unable to attain the high temperature we require for sterilisation
* Wetness also contributes to perforation of paper packaging material
Selection criteria of packaging materials
Labelling requirements for sterile packages
* Use indelible non-toxic felt tipped pens or skin marking pens (don’t use ball point pens as they may penetrate the wrapping material)
* Write on the tape or the clear side of laminate packs– not on the paper because the ink may bleed into the sterilised instruments
* Include content information, date of sterilisation, instrument type and staff member initials
Sterilising methods
What can survive boiling water (100C)?
Spores can survive 100C– boiling water at atmospheric pressure at sea level.
** Therefore we subject the steam to pressure to attain a much higher temperature so that bacterial and spore destruction is accomplished by coagulation, similar to the way an egg is poached
What are the four types of steam sterilisers?
How do benchtop sterilisers work (both drying and non-drying)?
Using distilled water (to avoid impurities that may interfere with sterilizing or damage the unit itself)– water is boiled and then pressure is added to achieve an even higher temperature.
How does the downward displacement steriliser work (jacketed)?
How do pre-vacuum sterilisers work?
What is the sterilisation temperature and relative holding times?
Sterilising time + safety margine time (half of recommended sterilising time) + penetration time= total holding (sterilisation) time
Drying time is in addition to the sterilisation process
What do we need to know about each steam steriliser load? What are the three methods of monitoring?
* Selected temperature has been reached, temperature was maintained for the required time
* 3 methods: Chemical, physical, and biological
What are chemical indicators?
What are the physical parameters as a method of monitoring steam sterilisers?
What is biological testing as a method of monitoring steam sterilisers?
Sterile storage ideally??
* controlled AC with low turbulence, minimal traffic, separate from other activities
* Sterile stock free from direct sunlight, dust, dampness, insects, vermin and constant handling
* Smooth washable surfaces with routine cleaning
* Storage away from water pipes, not stored under sinks
* Cardboard boxes are not recommended as they are porous and cannot be cleaned therefore potentially harbour contaminants
How is shelf life determined of sterile stock?
Montoring surgical site infections?
Base rates should be documented and logged with accompanying culture and sensitivity results
* no hospital has a 0% rate
* However need to know if there is an increase and take adequate measures to monitor and prevent
* most occur after discharge so follow up is essential
What is the gowning method for re-usable gowns?
Gowning methods for disposable gowns?
Aim of the surgical scrub
Criteria for surgical scrub antiseptic
Materials required for a surgical scrub
- cap and mask
- clean scrub suit (top tucked in)
- Disposable scrub sponge
- sterile gown, towel and gloves
Method for traditional water based hand scrub
- Open the scrub sponge and nail pick package but leave them safely in the package
- Turn on the water flow using either your elbow or sensor (adjust temp if required)
- The hands are kept above the elbows at all times to enable water flow towards the elbow
- Wet the hands and arms, then perform a general wash on the hands and lower arms using an antimicrobial agent
- The nails should be cleaned using the nail pick
- Rinse hands and arms under running water, and then apply a generous portion of the antimicrobial solution to both hands and arms
- Using the bristles of the brush, commence scrubbing at the fingernails, and then use the sponge on the hand
- Use the sponge in circular motion from the wrist and onto the arm, moving towards the elbow
- Finish just beyond the elbow without going back down the arm or the hand
- Rinse the sponge, transfer it to the other hand, commence scrubbing the second hand and arm
- Discard the sponge into the sink once finished
- Rinse the hands and arms thoroughly
- A sterile towel is used to dry hands and arms in aseptic manner by utilizing one end of the towel for one hand and arm, then the other end of the towel for the opposite hand and arm. Alternatively some gowns are packaged with two paper towels, one for each hand and arm.
Alcohol Hand Rub Method
Materials required for surgical skin preparation
Method for surgical skin preparation
When is open gloving used?
Intra-operatively if a change of gloves is required
* A non-sterile staff member shoulder assist removal of contaminated glove however if this isn’t possible a new sterile glove may be put on over top of the contaminated glove
Closed gloving method
Open gloving method
How do you hold articulating vs. non-articulating instruments?
What is a benefit to using a scalpel over scissors?
Less crushing of tissue compared with scissors
* Best for tissue that is dense or can be held under tension
What are the primary scalpel blades and handles used?
Which blades does the Bard- Parker number 4 handle receive?
Larger blades (#20,21,22,23)
What are the different scapel blades and what are they used for?
What are the grips that can be used with scapels?
What does the non-dominant hand do while cutting with the scalpel?
Create lateral/longitudinal tension to promote wound separation, stabilize tissues, improve cutting efficiency and facilitate visualization during creation of a skin incision using a scalpel
What is slide cutting?
What is press cutting (stab incisions)?
What is sawing?
What is scraping?
Benefit to curved scissors? Benefit to straight scissors?
* Curved scissors offer greater manoeuvrability and visibility
* Straight scissors provide greatest mechanical advantage when cutting tough or thick tissue
What are mayo dissecting scissors used for?
Cutting dense, heavy connective tissue such as fascia
What are metzenbaum scissors used for?
More delicate than Mayo scissors– are designed for sharp and blunt dissection or incision of finer tissues
What are some examples of delicate scissors and uses?
* Tenotomy and iris scissors
Used in ophthalmic procedures and other meticulous surgeries such as perineal urethrostomy that require fine, precise curts
What is special about bandage scissors?
Blunt tip to avoid cutting skin when introduced under the bandage
Where would you use scissors over a scalpel?
Scissors are better for cutting flaccid tissues because the scissors stabilize the tissue
What is the correct way to handle scissors?
What are the different uses of scissors (3)?
Mayo-Hegar vs. Olsen-Hegar needle holders?
Needle holder technique
How to hold and drive needles
Describe the three grips of the needle holder and why
What are hemostatic forceps?
Crushing instruments used to clamp blood vessels.
Examples of hemostatic forceps? Longitudinal v. transverse striations?
3 inch Mosquito hemostats with transverse jaw serrations
Larger 9 inch angiotribes– Kelly, Crile, Mosquito with transverse serrations
** Rochester- Carmalt has longitudinal serrations
** Longitudinal serrations generally gentler to tissue than cross serrations– as little tissue as possible should be grapsed to minimize trauma and the smallest hemostatic forceps possible
How do you hold hemostats?
Wide based tripod grip. Fingertips should be placed on the finger rings or fingers should be inserted into the rings only as far as the first joint.
Why are curved hemostats preferred?
Rochester
-
Carmalt
haemostatic
forceps
Halsted mosquito haemostatic forceps use?
Kelly and Crile haemostatic forceps use?
Rochester-Carmalt haemostatic forceps use?
What are tissue forceps used for?
Grasp or clamp tissue– vary in the degree of trauma created.
What are the crushing forceps?
What are the non-crushing tissue forceps and their uses?
What are the right angled forceps and their use?
What are the four different types of thumb forceps and their uses?
Different types of towel clamps?
Different uses for each of these?
Balfour self-retaining retractor (top)
Gosset retractor (bottom)
What are the Senn and Mathieu retractors used for?
Similar– both have three sharp or blunt prongs on one end with a right-angled flat, curved blade on the other. They can be used to retract skin and superficial muscle layers but have relatively little use for retracting a large muscle mass.
What are Meyerding finger retractors used for?
Right angled shape with a single-ring handle and different sized gripping blades with serrated/ toothed edges. They are used to retract large muscle groups in orthopaedic surgery (e.g. long bone or pelvic fracture repair, THR)
What are hand held retractors used for?
What are the self-retaining retractors?
(also Finochietto rib retractor and Haight baby rib spreader)
How do you maintain exposure to the thoracic cavity?
What is a ring retractor used for and example?
e.g. Long star retractor
Broad blades at each end with the depth varying for deep or shallow retraction. Used for large muscle retraction during orthopaedic and neurological procedures
What are army-navy retractors used for?
Orthopaedic retractors
What are Hohmann retractors used for?
Examples of currettes and what are they used for?
What are the bone holders (5)?
What is electrocoagulation?
Electrosurgery is a form of energy transfer via electrons from instruments to tissues
What is monopolar coagulation?
Where is electrosurgery most effective?
What is bipolar coagulation?
What is EBVS?
What is the ForceTriad system?
What are the parts of the scalpel?
Edge, spine, and slot, handle, blade lock
What is the No. 10 blade used for?
Large, curved cutting edge– large incisions in the skin and subcutaneous tissue (and other tissues)
What is the No. 11 blade used for?
Triangular blade– stab incisions, precise, short cuts in shallow, recessed areas. e.g. creation of incisions for chest tubes and drains, opening major blood vessels for catheter insertion, removing the mop ends of torn cruciate ligaments, and meniscectomy
What is the No. 12 blade used for?
Small, pointed, crescent shaped blade– suture cutter, cat declaws and disarticulating small joints such as between metacarpals, metatarsals, and phalanges during digit amputation
What is the No. 15 blade used for?
Very popular– short precise incisions– excision of small skin lesions, organ biopsy, and fine neurological applications
What is the No. 22 blade used for?
Larger version of the No. 10 blade– large incisions through thick skin and for soft tissue dissection in large- animal surgery
What is the standard scalpel handle used in veterinary surgery? What is it used for? And what is a variation?
3 size– skin incisions and cutting superficial tissues such as the subcutaneous tissues (#3L has a longer handle making it suitable for incising deep, remote areas such as the thoracic cavity)
How do you properly arm a scalpel?
Have a non-sterile assistant peel back the package, use the neele holders to grasp the blade in the jaws on the spine of the blade just about the blade slot
* can also drop the blade onto the sterile surgical tray but not preferred as can get lost or cut through the drapes
How do you properly disarm a scalpel?
Using non-dominant hand grasp the surgical scalpel in the center of the handle (cutting edge away), use the tip of the needle hodler to grip the slanted edge of the blade base
Handing off a scalpel?
Grasp in the middle of the handle, blade pointed away from both people, the person who it is handed to does not move it away until the other persons hand is clear
Advantages and Limitations of the pencil grip
* advantages: short, fine movements for small, precise incisions
* Limitations: 30-40degree angle to the tissue which diminishes the cutting edge contact limiting both depth and direction control– not ideal for long, straight incisions
Advantages and limitations of the fingertip grip?
* Advantages: good depth and direction control because it maximizes the length of blade that comes into contact with the tissue… any changes in blade pressure are distributed over a greater length which delivers less pressure to each increment of tissue and allows for greater security of depth control
- also allows for smoother, straighter incisions
* Limitations: Not precise– not used when delicate, precise scalpel cuts are required such as ophthalmic and vascular procedures
Advantages and limitations of the palm grip?
* Advantages: Strongest most secure way to grasp the handle but is rarely indicated- mainly when great pressure is needed to cut through very dense tissue e.g. cutting open cadavers during necropsy
* Limitations: Less control and accuracy
What is press cutting? What are advantages? Limitations?
* Pencil grip– increase downward pressure on the blade tip, the blade will pop through targeted tissue e.g. stab incision
* Advantages and applications: wound is well controlled in both length and direction as it is the exact width of the scalpel blade… often used to drain abscesses, open the bladder, stomach and intestines
* Limitations: Depth control is not precise
What is a slide cut? Advantages? Limitations?
* scalpel grasped in the fingertip grip, sliding the blade on its cutting edge while exerting a sub-bursting pressure on the tissue… cutting motion at a right angle to the direction of scalpel pressure, depth is determined by pressure exerted, length of blade distributing the pressure and the resistance to cutting of the tissue being incised
* Advantages: depth control is precise… most veterinary procedures, especially skin incisions because accurate depth control and precise direction and length control
* Limitations: does not allow for short, deep incisions in tissue
What is scrape cutting? Advantages? Limitations?
* Pencil or fingertip cut (pencil for delicate tissue such as anal-sac wall)…. like shaving hair with a razor blade
* Advantages and applications: precise way to separate layers of tissue without cutting the deeper layers beneath the blade known as button holing. Used for developing pouches for devices and the separation of fascial planes in reconstructive surgery e.g. when separating fascia during mastectomy, separating muscle attachments to the anal sac without rupturing the deeper, thin sac wall during anal sacculectomy in dogs, cats, and ferrets
* Also some security from perforating surfaces when releasing adhesions and in scarifying the serosal surfaces of viscera for purposefully creating an adhesion e.g. colopexies for recurrent rectal prolapse
* Limitations: Not efficient for incising tissue. More traumatic to tissues than sharp dissection with a slide cut.
What is the problem with devitalized islands?
Happens when surgeons retrace their first incision– leads to wound complications after closure
Ideal cut of the first skin incision depth?
Cut the skin just beyond the hypodermis but not into the deeper subcutaneous tissue where larger blood vessels can be damaged– then you can visualize and ligate larger blood vesslels or sealed with electrocoagulation before they are incised
Name some absorbable natural fibres, absorbable monofilament, absorbable multifilament?
Absorption rates of catgut? Why does it lose tensile strength rapidly?
Loses tensile strength rapidly because phagocytosis is important in its absorption– it also loses tensile strength in a non-predictable fashion
What is PGA? How is polyglycolic acid (PGA, Dexon, Dexon II) absorbed?
Braided multifilament suture
Absorbed by hydrolysis
Although initially strong it rapidly loses its strength (e.g. 33 percent loss in seven days and 80 percent loss within 14 days). Completely absorbed within 120 days
** markedly reduced inflammatory response compared with catgut
* Disadvantages: tendency to drag through tissue and poorer knot security when compared with catgut
What is Polyglactin 910 (Vicryl)?
Braided suture which is coated to improve its handling and knotting characteristics
More resistant to hydrolysis than PGA
Vicryl loses 50% of its strength by about two weeks and is totally absorbed within 60-90 days (there is also Vicryl Rapide, loses 50% tensile strength by 5 days and all between 10-14 days)
Advantages: Well tolerated in many different wound conditions, excellent size to strength ratio, relatively easy to handle, stable in contaminated wounds and elicit minimal tissue reaction
What is Polydioxanone (PDS)?
Monofilament suture that like PGA and polyglactin 910 is degraded by hydrolysis but at a slower rate
* Loses 26% of its tensile strength in 14 days, complete by 182 days
* PDS is very strong and causes little tissue reaction and less tissue drag than multifilament suture materials
* Improvements have been made in its handlign characteristics (PDS II)
* Care required when tying knots because of its high memory
What is Polyglyconate (Maxon)?
Monofilament suture material with similar tensile strength to PDS
* Loses strength in a similar fashion e.g. 19% after 14 days, 70% after 42 days
* Absorbed by macrophages between 6-7 months after implantation
What is Poliglecaprone 25 (Monocryl)?
Relatively new monofilament suture that is prepared from copolymer of glycolide and E-caprolactone
* Progressive loss of tensile strength and eventual absorption by hydrolysis
* Dyed form loses strength by 21 days, undyed form by 28 days
* Elicits minimal inflammatory reaction in tissues, easy to handle (lower memory than other monofilament synthetic absorbables), good knot security
When would you use non-absorbable sutures?
Discuss silk as a suture material
* Braided multifilament suture material (Mersilk), which may be coated to decrease natural capillarity
* Non- absorbable, howevere loses tensile strength and is absorbed in approx 2 years
* Inexpensive and excellent handling characteristics but it causes marked tissue reaction and is inferior to many suture materials in strength and knot security
* do not use in the lining epithelium of hollow viscera and should be avoided in contaminated wounds
Nylon as a suture material
* Monofilament or multifilament
* minimal tissue reaction
* permanent– slow hydrolysis losing 30% of tensile strength by 2 years
* Disadvantage: poor handling characteristics and knot security
* Braided form handle and knot better but suffer inherent capillarity
* Do not use within serosa or synovial cavities because buried sharp ends may cause irritation
Polyester (Mersilene) suture material?
* Braided multifilament– plain and coated forms
* Extremely strong with prolonged support for slow healing tissues
* poor knot security and causes the most tissue reaction of any of the synthetic suture materials
Polypropylene (Prolene) as a suture material?
* Monofilament suture that has a lower tensile strength than nylon
* Retains its strength on implantation, is not weakened by tissue enzymes and is the least thrombogenic suture
* Frequently used in vascular surgery
* Disadvantages: high memory and poor knot holding ability
Polybutester (Novafil) as a suture material?
Special type of polyester suture which possesses many of the advantages of both polypropylene and polyester
* Good tensile strength and knot security
Stainless steel as a suture material?
Available as a monofilament or multifilament suture material
* Biologically inert, non-capillary and has the highest tensile strength of all of the suture materials
* Main use is in tendon and ligament repair
* Disadvantages: tendency to cut tissues, poor handling characteristics (especially knot tying) and relatively poor ability to withstand repeated bending without breaking
Non-absorbable suture materials
What is the most common tissue adhesive? Most common problems?
Cyanoacrylates
* Tissue toxicity, granuloma formation, wound infections when used in contaminated sites, delayed healing if wound edges are separated, poor adhesion on excessively moist surfaces
When are surgical staples used?
Quick alternative– e.g. gastrointenstinal anastomosis, skin apposition and pulmonary, cardiovascular and hepatic resections
* Advantages: improved efficiency, consistency of application and haemostatic security and ease of use in areas of difficult accessbility
* Do not use excessive amounts, should be inspected to ensure no mechanical failure of stapling device
What are ligating clips used for?
Neutering, splenectomy and intestinal resection
* Quick and easy to apply– useful in areas of limited accessibility
* Limited to use on vessels that are less than 11 mm in diameter
* Metallica and absorbable clips are available
Appropriate suture materials for different tissues
Minimum number of throws for a secure knot
Number of throws required for continuous suture patterns
What happens if only two throws are used?
Suture pattern choice for skin
* appositional patterns for rapid healing: simple interrupted, continuous intradermal, simple continuous, Ford interlocking
** Simple interrupted should be placed at least 5 mm from the wound edge and at an interval of 5mm to produce maximal wound strength
GIT pattern of suturing
* IN the past inverting patterns were used (Cushing, Lembert, Halsted or Connell)
* However now more appositional reconstruction is used with simple interrupted or simple continuous
* Synthetic absorbables are most frequently selected in the intestine because of their comparatively long retention of tensile strength and reduced tissue response
* Bladder– single or double layer appositional sutures = more rapid healing but still strong enough
Laparotomy closure?
* Closure of peritoneum or rectus and oblique muscle layers is unnecessary and many contribute to ischaemia in these layers and increase the risk of abdominal adhesions
* Synthetic absorbables are preferred to natural absorbables and retain tensile strength for permanent materials (monofilament nylon or polypropylene) not to offer significant advantage here
What is the mattress suture pattern?
What are appositional, inverting, everting, and purse string suture patterns?
Why is their controversy between using simple or continuous pattern for laparotomy repair?
* Dehiscence risk with continuous pattern
* Modern synthetic absorbable materials with adequate throws at each end of the suture (minimum of six for monofilament materials) is perfectly safe
** Additionally, less suture material is left in the wound and tissue response is minimised
Concern with contaminated or infected wounds and suture material
* Risk of bacterial adherence within the suture material
* Braided or multifilament materials are prone to persistence of bacteria within the interstices of the fibres where they are resistant to removal by macrophages
** IN the presence of contamination or established sepsis, surgeon is wise to choose either monofilament material, which is more resistant to bacterial adherence or an absorbable material, which will be removed from the wound altogether with any associated bacteria
** Size of the knot and amount of suture material required may be responsible for the persistence of bacteria in suture material and the formation of sinuses
Suture removal
* 7-10 days– skin bursting strength is only 10-20% of normal but it minimises the inflammatory and infectious processes which are encouraged by sutures
* There are rarely any problems with wound dehiscence as most of the stresses are taken up by underlying fascia
* If tension is a problem, it may be better to leave sutures for 14-21 days…
* Where tension sutures have been interspersed between appositional sutures, they are usually removed after three to five days
What suture material has the highest tensile strength? lowest tensile strength? (OF ABSORBABLE)
** same question– nonabsorbable?
Poliglecaprone 25– highest initial tensile strength of absorbable suture material and surgical (chromic) gut has the lowest
** Stainless steel strongest– and silk is the weakest
What suture material has similar mechanical properties of skin?
Polypropylene and nylon
When closing a body wall with a continuous pattern of polyprolylene suture– guidelines for size?
* One size larger than usually recommended because sometimes the need for mechanical support is more critical then the need to minimize tissue reaction
What is an example of a situation where the need to minimize tissue reaction predominates?
* closure of visceral wounds or subcutaneous tissue (vs. closing body wall)
Why should a vet resist the temptation to use large suture materials routinely because they provide more secute knots?
Because they cause excessive tissue reaction
How many throws when using polyglactin 910, polyglycolic acid, surgical gut, or polyproplylene?
Polydioxanone or nylon?
* Three throws to make a secure knot in an interrupted pattern with polyglactin 910, polyglycolic acid, surgical gut, or polyproplylene
** Four throws with polydioxanone or nylon
With a continuous pattern using polydioxanone, surgical gut, or nylon– how many throws?
One more than an interrupted pattern
** the ending knots of a continuous pattern tend to be the least secure and require at least five throws– or more if polyglactin 910, nylon, or polydioxanone is used
Which is stiffer e.g. less pliable– monofilament or multifilament?
* monofilament tends to be stiffer– also later diameter suture are stiffer
* silk is the least stiff
Causes of tissue reactivity?? Contaminated wound and suturing?
Amount of suture material in the wound and the placement technique
** the presence of any suture material increases the tissue susceptibility to infection thus vet should avoid placing suture in a contaminated wound unless it is essential for positioning the tissue
** Monofilament sutures withstand contamination better than multifilament– monofilament: polydioxanone, polyglyconate, poliglecaprone 25 are preferred absorbable, monofilament sutures for contaminated wounds… polypropylene and monofilament nylon are the preferred nonabsorbable contaminated sutures
Tissue reactivity to sutures problems
* leads to increased morbidity– intensified or prolonged inflammatory phase of wound healing or enhanced patient awareness of the wound and subsequent self-mutiliation
** natural are more reactive than synthetic
What is an example of a surgery where strong adhesions at the surgical site is desired?
Perineal herniorraphy
Inflammatory reactions to sutures most pronounced what part?
Knots– as the highest density of foreign matereal and they cause the greatest mechanical trauma in tissue
** knot size or volume (suture size and number of throws dependent) affects tissue reactivity
* An increase of two suture sizes results in more than a four to sixfold increase in knot volume and more than a two to three fold increase in tissue reactivity
** Excessively tight suture lines increase patient morbidity and reduce short and long term strength in fascial wounds– but you may need a tight suture
Why is polydioxanone and polyglyconate appropriate to use in body walls?
Absorbable suture materials that lose tensile strength more slowly are appropriate to use in body walls because fascia heals slowly
What should you never use on the bladder or near urine?
Polyglactin 910 and polyglycolic acid as urine weakens them…
One benefit to continuous patterns?
Use less knots than interrupted patterns and less suture material in the wound
Unrelated to suture material, what is another cause of inflammation at the wound?
Excessively traumatic tissue handling– use of eyed (nonswaged) needles and excessively tight sutures– all enhance tissue reactivity
What suture material should be used on skin?
Polymerized caprolactum, polypropylene, nylon, stainless steel, polypropylene with fluorescent pigment
What suture material should be used on viscera?
* heal relatively quickly– usually attain full tensile strength by 21 days after surgery
** GIT : absorbable suture material, synthetic especially due to low reactivity– polydioxanone and polyglyconate
** plus relatively small (3-0 to 5-0) diameter and swaged needles are recommended for GIT surgery
* Urinary bladder- polydioxanone and polyglyconate– tensile strength maintenance even in contact with urine
** generally viscera– absorbable and minimally reactive
What suture material for the body wall?
Requires prolonged support because fascia heals relatively slowly
* Synthetic absorbable preferred– polydioxanone or polyglyconate because of their prolonged maintenance of tensile strength
** alternatively synthetic nonabsorbable: polypropylene, monofilament nylon or monofilament stainless steel– stainless steel fascial staples compared favorably with simple continuous pattern of polypropylene
Surgical instrument layout
Opening a sterile instrument set without contamination
Method for draping
* place near drape, top or tail and then opposite
peel off adhesive before placement
leave large laparotomy sheet folded and place it onto the patient, then carefully unfold the drape to cover the patient and the operating table completely
What is the sterile field?
Instrument table containing the unwrapped pack of instruments placed over the table
Front of the gown from chest to table level and the sleeves from above the elbow to the cuff
Correlation between sterilizer temperature and pressure
Appropriate temperature required for sterilization?
* Steam in itself is inadequate for sterilization, pressure greater than atmospheric is necessary to increase the temperature of steam
** Therefore we subject the steam to pressure to attain a much higher temperature so that bacterial and spore destruction is accomplished by coagulation, similar to the way an egg is poached
Spores can survive 100C– boiling water at atmospheric pressure at sea level.
** Therefore 121 C at 101 Kpa (kilopascal) for 15 minutes
Biocidal agent
Chemical substance intended to destroy or render harmless any harmful organism by chemical or biological means
Bio-burden
Number of bacteria living on a surface that has not been sterilized
Closure of the linea alba in a 40 kg dog– suture material
Immature cat spey?
< 5 kg- 3/0
5-20kg- 2/0
20-40 kg- 0
>45 kg- 1
Calculate a drug to be administered when provided with
* An intended dose in mg/kg OR in percent (as an additive to a solution
* Body weight of the patient
* given the concentration of the drug in mg/ml, g/ml, or percent
Placement of Intravenous catheter
* 18- 22 gauge catheter
* 3-12 mm syringe filled with saline
* 3 pieces of tape
* Clippers, chlorhex and alcohol
* Cephalic vein of the forelimb (or lateral saphenous vein of hindlimb)
* Clip and disinfect with chlorhex and then alcohol
* helper needs to hold off vein
* Tense the skin to fix the vein
* Catheter introduced by dominant hand looking for blood then reduce the angle, hold the stillette with the non-dominant hand, and move the catheter forward (keep forward pressure on the stilette)
* remove stilette and place T-port (closes it off)
Set up for IV fluid therapy
Subcutaneous fluid therapy
- Identify the appropriate site(s) in different domestic animal species and demonstrate proper technique for subcutaneous fluid administration
Birds- inguinal and/or axillary regions
Identify appropriate sites in different domestic species for subcutaneous and intramuscular injections, demonstration of appropriate technique
Subcutaneous- mammals- intrascapular, neck, shoulder, flank
Calculate the fluid deficit, maintenance requirements and ongoing losses from a cardiovascularly stable but dehydrated patient
Deficit (ml) = Estimated deficit (%) x BW x 1000 ml/ 1 L
i. e. 10 kg dog, 5% deficit: 0.05 x 10 x 1000 = 500 ml
i. e. 20 kg dog, 10% deficit: 0.10 x 20 x 1000 = 2000 ml
** Maintenance
Example:
- Estimated fluid deficit: 5 kg x 0.07 x 1000 ml = 350 ml
- Calculate maintenance rates: (5x30) + 70 = 220 ml
- Consider ongoing losses– measure each 4 hours and increase fluid rate by that much for the next 4 hours
- Divide by 24 hours to get per hour fluid rate: 350 + 220= 570 ml/ 24 hours = 24 ml/hr
** If acute can replace 1/2 over the first 6-8 hours and then the remaining over the next 16-18 hours
How to administer subcutaneous fluids
Write a prescription for acute fluid resuscitation for a patient with moderate hypoperfusion secondary to hypovolemic shock.
20 ml/kg isotonic crystalloids such as Lactated Ringers (Hartmann’s solution) or isotonic saline
* IV route: cephalic, saphenous, jugular or itraosseus if venous access fails (subcutaneous not recommended)
3 risk factors for developing complications of fluid therapy.
Name one form of shock where fluids are contraindicated.
Cardiogenic shock– poor delivery of oxygen to tissues due to heart failure. Distended jugular vein oftne. In patients with heart failure it is vital not to administer IV fluids if they have evidence that their circulation is already fluid overloaded e.g. pulmonary oedema secondary to congestive heart failure– giving fluids would make this situation worse
Determining percent dehydration
How do you recognize when more fluids could be harmful?
Selection of an appropriate circuit for a given anaesthetic scenario
Non-rebreathing circuit used for smaller patients (< 5 kg)
* simpler system
* Oxygen flows through a flow meter and into the vaporizer– gases exit the vaporizer to the hose to the patient with no inhalation flutter valve. Exhaled passes go through another hose–> reservoir bag with NO CO2 absorber–> released into a scavenger
** Rebreathing System (circle)– used for patients > 5 kg
* Reservoir bag-> inhalation valve–> inspiration hose–> animal–> expiration hose–? exhalation valve–> CO2 canister–> back to the inhalation valve
** Closed system (pressure relief valve is completely closed– only with low flow techniques)… Semi- Closed with pop-off valve open or partially closed– used with medium or high-flow techniques in which oxygen delivery exceeds oxygen consumption and excess gases are eliminated through a pressure relief valve (SAFER for the animal AND more rapid change in anaesthetic concentration)
Vaporizer
Vaporizer Hazards
Incorrect agent, tipping, overfilling (info on other FC)
Liquid anaesthetic agent level indicator
Keyed filling/ draining system
Fresh Gas Outlet
APL or Popoff Valve
Hazards of the APL or popoff valve
Canister
Hazards of the Canister
Gas Outlet and Inlet Block with Valves for Rebreathing System
Pressure Gauge or Manometer
scavenging system
Hazards of the scavenging system
Suction applied. Active systems require a means to protect the patient’s airway from the application of suction, or buildup of positive pressure.
Waste gases passively proceed down corrugated tubing through the room ventilation exhaust grill of the OR. Passive systems require that the patient be protected from positive pressure buildup only.
Compressed Oxygen supply
Oxygen central supply v. E cylinder
Two kinds of breathing systems.. what does it depend on?
How is CO2 eliminated from the system? Is there a CO2 absorber canister?? Yes?? then you have a rebreathing system like the Y piece or Universal F
Rebreathing systems with CO2 canister absorber
Non- rebreathing system without CO2 absorber
* The CO2 will not be eliminated through absorption but through the use of high flow fresh gas (O2 or O2 based gas mixture) pushing the CO2 away from the patient into the scavenging system.
Non- rebreathing system without CO2 absorber
* The CO2 will not be eliminated through absorption but through the use of high flow fresh gas (O2 or O2 based gas mixture) pushing the CO2 away from the patient into the scavenging system.
Components of the Rebreathing system AND advantages and disadvantages??
How do you connect patients to the rebreathing block?
Components of the non-rebreathing system
Advantages and Disadvantages to the Non-rebreathing system
Anaesthesia Machine Check
Leak test of a rebreathing system
Leak test of Mapleson D system
Leak test of non-rebreathing system (T piece of Mapleson F)
Endotracheal tube selection
Digital palpation of the tracheal out diameter
** can choose three– one based on weight of the animal, one half size bigger and one half size smaller– first try with the largest and switch if need be.
** avoid inadvertent placement into the lung
Elecrosurgery involves the use of an electrical current which is passed between two electrodes, producing heat within the tissues. The heat is produced as a result of the tissues:
Resistance
Routinely sterilised by?
Stainless steel instruments?
Flexible endoscopes?
Packaged suture materials?
Stainless steel instruments- Steam under pressure
Flexible endoscopes- Peracetic acid or high level disinfection OPA Cidex
Packaged suture materials- Gamma irradiation
Most effective way to control diffuse capillary bleeding from the surface of a parenchymatous organ is:
Both oxidised regenerated cellulose or gelatin promotes clot formation on the bleeding surface. A large surface area of bleeding can be covered. Local compression can produce the same effect but is time consuming. Electrocoagulation is not very efficient when a large area of diffuse bleeding is presented, and tends to char tissues. Suction can disrupt clot formation.
Metzenbaum scissors are recommended for dissection of delicate tissues because:
Gross movement of the shank is translated to fine movement of the blades
Which instruments can be used to safely hold the small intestinal wall without causing excessive trauma?
Babcock tissue forceps
How much blood approx is contained in a blood soaked surgical swab?
10 mL
What type of steam is required for correct sterilisation?
Dry Saturated Steam
Minimum number of throws when tying a suture knot?
Which material is traditionally used to tie ligatures around large blood vessels?
* 3
* Silk
Correct order applying solution to prep a patient for surgery
- Chlorhexidine scrub solution
- 70% alcohol spray
- Chlorhexidine in 70% Ethyl Alcohol
Povidone Iodine is sometimes used instead of Chlorhexidine for the following reason:
Antifungal property
What property of Nylon makes it difficult to handle?
High memory (difficulty in handling and decrease in knot security)
Polydioxanone (PDS) loses 50% of its tensile strength in how many days?
28 days
What type of knot would be used to tie a secure surgical knot?
Square knot
Horizontal Mattress suture
Vertical Mattress Suture
Modified transfixation ligature
Often circumferential ligature first proximal to the patient, then transfixation ligature (as when you pass the needle through the center it will bleed)
https://app.lms.unimelb.edu.au/webapps/blackboard/content/listContent.jsp?course_id=_292975_1&content_id=_5035520_1
Steps to ligating an ovarian pedicle
What would be an appropriate suture material and size for ligating the ovarian pedicles in a 4 kg cat?
Explanation: 3-0 absorbable monofilament(eg. PDS, Monocryl) is an appropriate suture material. An absorbable multifilament (eg. Vicryl, Dexon) would also be considered appropriate.
Rules for building consistently secure ligations
Ideally, if the clamp can be
flashed, attempt to move the ligature so it falls in
the crushed area of pedicle after the hemostat has been “flashed”.
Tension on the pedicle during knot tying also tends to loosen the first throw
of a ligation. This tension also tends to fan or spread o
ut the pedicle which
increases the risk of loosening of the first throw. If the first throw loosens
just a small amount, this could result in fatal hemorrhage. Use a Miller’s or
Strangle knot when tension on the pedicle cannot be avoided. This happens
c
ommonly when attempting ligation of a relatively short ovarian pedicle
during ovariohysterectomy in a deep
-
chested dog.
Choose strong suture material with good knot security. Place firm, slow and
even tension on the knot throws during tightening so the th
rows are
squarely fashioned. Avoid sawing suture strands as the ligature throws are
“pushed down” toward the pedicle. This significantly weakens the strands
and knot. Knot ears should be at least 3 mm for synthetic sutures to help
keep the final throw o
f the knot from unraveling.
Why is a surgeon’s knot not necessarily recommended for ligation?
Three clamp technique on ovarian pedicle
Miller’s knot
