Clinical Skills Year 3

when preparing a patient for surgery what preparation do you need to do for your own hands?

normal handwashing and wear non-sterile gloves

what is the overall purpose of asepsis?

to prevent bacterial contamination of the inside of the patient's body during a surgical procedure

can you describe your hands as sterile?

no, only inanimate objects can be rendered totally sterile so we use aseptic technique to minimise bacteria on our hands

Antiseptics are used on?

living tissues

Disinfectants are used on?

inanimate objects and surfaces

what can disinfectants not destroy?

the spores of pathogenic organisms

what two things do you need to know about your antiseptic or disinfectant to use it correctly?

concentration of the preparation and the contact time required

what are the three most common antiseptics seen in practice?

chlorhexidine, iodophors or alcohol-based

which antiseptic is inactivated by contact with organic matter?

povidone iodine

what are three disadvantages of povidone iodine over chlorhexidine?

it requires longer contact time (due to inactivation by contact with organic matter), it has been shown to cause skin irritation, and it is not as effective in preventing bacterial regrowth.

what property of chlorhexidine makes it so effective at preventing bacterial regrowth?

it binds to the stratum corneum

what is the main benefit of using alcohol based gels?

they require a shorter contact time

which has better residual activity chlorhexidine or alcohol based gels?

chlorhexidine

why is it still important to wear gloves once you have scrubbed your hands and arms?

you only render your hands 70-80% sterile by scrubbing so you should still wear sterile gloves for surgery.

why is it still important to scrub your hands if you're going to wear sterile gloves for surgery?

because you can easily tear or puncture surgical gloves (without even realising) so you need to be able to minimise contamination of the patient

when might a surgeon wear two pairs of surgical gloves?

in animals at higher risk of surgical infection or if there is expected to be a dirty and clean stage of the surgery.

what is the order in which you would scrub in for surgery?

remove glasses and wear contact lenses, tie back hair and wear surgical cap, put on surgical mask, wash hands, perform hand scrubbing or rubbing, closed gloving and gowning

what do you need to consider when using chlorhexidine to aseptically prepare your forearms?

you must not use the scrubbing brush as you will have when scrubbing your hands because it is too abrasive and will induce inflammatory secretions which bring bacteria deep in the hair follicle to the surface.

which sort of procedure might open gloving be suitable for?

a minor procedure which does not invade a body cavity such as a stitch up

what is the purpose of surgical drapes?

to prevent contamination of the surgical site by other parts of the animal

what is the infection rate in a clean surgical wound?

2-4.8%

describe a clean surgical wound?

elective surgical wounds not entering gastrointestinal, respiratory or urogenital tracts. no break in aseptic technique.

what is the infection rate in a clean-contaminated surgical wound?

3.5-5%

describe a clean-contaminated surgical wound?

surgical wounds entering the gastrointestinal, respiratory or urogenital tract. Minor contamination or break in aseptic technique.

what is the infection rate for a contaminated surgical wound?

4.6-12%

describe a contaminated surgical wound?

fresh open wounds less than 4-6 hours old. major break in asepsis.

What is the infection rate for a dirty surgical wound?

6.7-18.1%

describe a dirty surgical wound?

traumatic wounds greater than 4-6 hours old. Wounds with devitalised tissue. Surgery in the presence of clinical infection or perforated viscera.

which antiseptic is commonly used for preparation of the patient's surgical site?

chlorhexidine

which antiseptic might be selected for preparation of patients for ophthalmic surgery and why?

povidone iodine because chlorhexidine can cause damage to the cornea.

what is primary intention in wound healing?

wounds closed by suturing with dermal edges that are close together for example when made by a scalpel.

what is tertiary intention in wound healing?

wounds closed by suturing but not immediately (eg. wound might be left open due to infection risk)

what is the difference between absorbable and non-absorbable suture material?

absorbable sutures are broken down by the body by hydrolysis or proteolysis and therefore is commonly used for closure internally. non-absorbable suture material is manually removed once the wound is healed and so is commonly used for skin closure.

what might happen if you pick a suture material which is too thick?

there is more material in the wound than necessary which can be a nidus for for infection or cause additional inflammation

what might happen if you pick a suture material which is too thin?

it may fail, leading to wound breakdown

what are the two measurement methods for suture material diameter?

metric or USP

how do you interpret metric gauge suture material diameter?

higher number means larger diameter. The number is equal to 0.n mm diameter.

what is the smallest USP size?

11/0 which is 0.01mm

what is the largest USP size?

7 which is 0.9mm

how big is USP 0?

0.35mm

how is multifilament different to monofilament?

multifilament suture material is braided and so causes more drag and is more likely to harbour bacteria. However it also has less memory and so it is easier for knot tying.

what are the three different shapes that needles can come in?

curved, straight or j-shaped

what are the two different point styles of needles?

round or cutting

in which tissue types might you consider using a round need instead of a cutting one?

in softer tissues to reduce the risk of suture cut out.

what is an advantage of swaged on suture material over eyed-needles?

the eye increases the diameter of the needle so can increase trauma

although reusing needles is cheaper, what is the major disadvantage to the patient?

they become blunt over time and cause more tissue trauma

what are the advantages of interrupted suture patterns over continuous ones?

if one suture breaks down the rest remain in place.

what are the advantages of continuous suture patterns over interrupted?

quicker to place and tension evens out along the suture line

describe appositional suture patterns?

apposition means the tissues are held in normal anatomical alignment

describe tension relieving suture patterns?

similar to appositional or possible slightly everting to relieve tension

describe inverting suture patterns?

cause tissues edges to invert relative to each other, reducing the amount of suture on the organ surface and so reducing the risk of adhesions. Used in hollow organs such as bladder and uterus as they produce a seal which prevents fluid leakage

when suturing skin, when is it imperative that you use a surgeon's knot first?

when using a continuous suture pattern. If interrupted either a surgeon's or square knot is fine.

what are some of the potential implications of rough tissue handling?

ischaemia of the skin edges, increased risk of infection, prolonged healing times and excessive scarring.

what instruments would you use to suture hollow organs?

atraumatic forceps and round needle

what instruments would you use to suture skin?

Treves tissue forceps and cutting needle

what is the potential consequence of too many sutures too close together?

ischaemia of tissue edges

what is the potential consequence of too few sutures?

poor approximation of wound edges and subsequent delayed healing

how is the Cushing inverting pattern different from the Connell pattern?

it only penetrates the mucosa and submucosa but does not go into the lumen of the organ

what are the three surgical layers you need to close following an abdominal incision for a spay?

the linea alba, the subcutaneous, and the skin

what might happen if the linea alba sutures fail?

herniation of the abdominal organs

what are the three layers of the linear alba?

parietal peritoneum, the muscle itself and the outer fascia

which is the strongest (and therefore most important) layer of the linear alba to include in your sutures?

The external fascia

which layer of the linear alba do you not want to incorporate in your sutures and why?

the parietal peritoneum as you want it to move and seal off the incision. you also don't want suture material in the abdominal cavity where viscera can adhere to it.

when you close the linear alba do you want buried or superficial knots?

superficial to prevent adhesion of abdominal viscera

why is it important to close the subcutaneous layer?

eliminate dead space to prevent filling with fluid (seroma) and bring skin closer together to reduce tension

which pattern would you use to close the subcutaneous layer?

continuous pattern with buried knots (so they don't interrupt healing of the skin)

what is a good choice of suture pattern to close skin and why?

cruciate mattress due to mild tension relieving properties and speed of placement (half the number of knots as with interrupted)

which suture pattern not practised in clinical skills is good for minimising scarring or for when suture removal is inconvenient?

intradermal with an absorbable suture material

List some of the safety requirements for radiation safety in small animal practice?

controlled area, lead shield of 0.5mm, warning light, dosimeter present

who must not be within the controlled area when radiographs are taken?

pregnant people or anyone under 18

in large animal practice taking radiographs in the field, how large must the cordoned off control area be?

3m from x-ray generator/patient in all directions and 8m from the generator in the path of the primary beam.

even when wearing PPE, how far must people stand from the x-ray generator?

2m

in large animal practice taking radiographs in the field, what constitutes an adequately shielded wall or floor?

solid brick or concrete or a beam stop of 2mm thick lead sheet

list appropriate PPE for radiography within the controlled area?

lead gown, thyroid guard, dosimeter, lead gloves

what action can be taken by the person taking the radiograph to ensure minimal unnecessary exposure?

good collimation to reduce scatter and avoiding repeat exposures by ensuring good positioning on the first attempt.

who is responsible for radiation safety within a practice?

the radiation protection supervisor

how do you describe a radiographic view?

by describing the path that the X-ray beams have travelled in order to obtain that view

what is centring in radiographic positioning?

ensuring the centre of the x-ray beam is positioned over a specific palpable landmark for that view

what is collimation?

limiting the size of the primary x-ray beam to include only the pertinent anatomy

how can you check the collimation of your radiograph before taking it?

you can visualise it using the light source

how can you check the centring of your radiograph before taking it?

there is usually a cross in the middle of the light source

how is collimation altered prior to taking a radiograph?

you can use dials on the x-ray generator to open and close paired lead shutters

how do you select an appropriately sized plate for radiography?

the smallest available plate which fits all the pertinent anatomy

for a craniocaudal view of a limb, where would you place the L/R marker?

on the lateral aspect of the correct limb

for a mediolateral view of a limb, where would you place the L/R marker?

on the cranial or dorsal aspect of the correct limb

for a dorsoventral view where would you place the L/R marker?

on the corresponding lateral aspect

for a lateral view, how do you decide whether to use a L or R marker?

you use a marker to indicate the side of recumbency eg. the aspect of the patient in contact with the plate.

name some radiolucent positional aids

foam wedges and troughs

same some radiopaque positional aids?

rope ties and sand bags

under what circumstances can you use rope ties to position your patient for radiographs?

only when they are under general anaesthesia, under sedation sand bags must be used in case the patient moves and injures themselves

which part of the radiolucent trough should be kept away from the area of interest and why?

the edge of the trough as it may cause an artefact

what is meant by taking orthogonal views and why do we do this?

taking two views at right angles to each other, eg. craniocaudal and mediolateral views of the elbow, this reduces the chance of us missing or misinterpreting anything as radiographs are 2D representations of 3D structures

what are the two broad types of radiography?

conventional film radiography and digital radiography (direct or computed)

which type of radiography requires the use of a viewer?

conventional film radiography

a material's radiodensity is determined by?

how many photons are absorbed by the material (determined by atomic number and thickness)

order the materials you might see on a radiograph from most radiolucent to most radiopaque

gas/air, fat, soft tissue/fluid, bone/mineralised tissue, metal

which shows up as darker on a radiograph, radiolucent or radiopaque material?

radiolucent

how should you display a dorsoventral radiograph?

as if the animal is standing on it's hindlegs and facing you

how should you display a lateral radiograph?

with the cranial end of the left handside as you look at it

what are the 9 steps to interpreting a radiograph?

1. identify species and view, 2. check label, 3. assess positioning, 4. assess collimation, 5. assess exposure, 6. spot development faults, 7. identify artefacts, 8. describe the normal anatomy, 9. survey radiograph in systematic manner to identify abnormalities