Florida Atlantic University

Florida Atlantic University

Surgery Training Course

Presented by

Veterinary Services

Please note, if viewing these pages on an Apple machine, the images may not line up correctly. I have a print out in my office if needed.

This is the surgery lecture. It is required for all those doing survival surgeries and recommended for others using anesthesia and / or doing non-survival surgery.
Parts of lecture
1. Surgery is what you are here for. Most of you understand that to do surgery, we have to have the patient anesthetized. And, most of us can appreciate pain or the potential for pain associated with surgery. However, if we have not had surgery in a long while, then we may have forgotten how excruciating it can be. Lastly, we have to be concerned about distress for the animal. The other three are somewhat obvious but distress is something that we may forget to think about. And we have to learn how to recognize pain and distress in the species you plan to use.
Objectives
1. Understand legal requirements
2. Understand proper drug use
3. Understand proper surgical techniques
4. Care for the "whole" animal
General Training Course should have already taken this course. If not, give our office a call at 297-4233.
1. Regulations
2. Humane methods and care
3. Alternatives
4. Ethics
5. Husbandry
6. Veterinary care
Pain and Distress
1. Definitions
  1. Stress-external (physical/environmental) or internal (physiologic/psychological) factors that induce an alteration in an animal's homeostasis
  2. Distress-an inferred aversive state due to inability to adapt to a stress. Pain-sensation through nervous system
2. Categories
  1. Sensory (discriminative)
  2. Motivational (affective)
3. Duration
  1. Acute (short duration)
  2. Chronic (longer duration, not protective)
  3. One can generally endure a more intense pain for a short duration
4. Assessment
  1. Primarily observation
    1. Have to consider situation, drugs, etc.
  2. One of the most important part of your training which mostly come from your observation of the patient to learn the very earliest signs of distress and pain.

Anesthesia

Anesthesia
1. So, the first area to cover is anesthesia and analgesia. We will discuss the pharmacology of anesthesia.
2. General Anesthesia means a controllable loss of all sensation, unconsciousness, loss of pain sensation and muscle control. Used extensively in animals.
3. Local Anesthesia means a localized area that loses pain sensation. Does not render the animal unconsciousness nor without feeling, just without pain. Reserved for use in special situations and in special species such as cows.
Tranquilizers reduce anxiety and stress.
1. Very similar to sedative but generally not as deep.
2. Does not render the animal unconsciousness or without pain.
3. Used as pre-medication for ease of injecting the anesthetic.
Analgesics temporarily alleviate pain without causing loss of consciousness
Neuromuscular Blocking Agents reduce muscle tone without the loss of consciousness by acting on the neuromuscular junction (pancuronium) or on spinal synapses (mephenesin, guaifenesin)
1. Requires very special approval because it causes loss of reflexes, breathing, etc. without lost of pain perception.
General anesthesia
1. Definition: Produce unconsciousness, analgesia, and muscle relaxation sufficient to perform procedures painlessly
2. Examples:
  1. Injectable
    1. Barbiturates--sodium pentobarbital.
      1. Not reversible, must be metabolized, excreted.
      2. Not the best analgesic..
  2. Dissociate
    1. Ketamine depress CNS and produce a state of catalepsy, usually used with another substance to produce good
  3. Inhalants
    1. Halothane, Isoflurane
    2. Easily reversed
Anesthetics
1. Pretreatment
  1. Atropine (anticholinergic)
    1. Reduces some salivation (serous) and bradycardia.
  2. Tranquilizers
    1. Calm animal.
  3. Sedative
    1. Can depress the CNS.
2. Dosage
  1. Administer to effect
  2. Precise calculation then adjust for age, condition, procedure, species, other drugs, and other factors
3. General considerations
  1. May want to test on a few first.
  2. Consider the health of the animal, depth vs. safe, validity of experiment, equipment available, body heat, anesthetist, safety of personnel.
Anesthetic Evaluation
1. Stages
  1. Have different meanings.
  2. Should not use terms like Stage 3 since that depends on species and drug
  3. The animals generally go through several stages in which you may see each or only unconsciousness
    1. Stage of excitement
      1. This stage is generally seen when a drug is not given properly and there is slow enough pass though this stage that you see excitement by the animal
      2. Surgical anesthesia is unconsciousness, progressive depression of CNS, etc.
    2. The next stage is extreme CNS depression, death ensues quickly
2. Reflexes
  1. Such as toe pinch, ear pinch, ocular reflex, jaw tension, etc. are used to evaluate the animal. In general anesthesia, all reflexes are lost
3. Respiration
  1. Increases in depth and decreases in rate which indicates anesthesia
4. Heart rate
  1. Generally slows (increase with pain, light)
5. Body temperature
  1. Falls with anesthesia (need to maintain at normal)
  2. Most severe in rodents and when xylazine is used
6. Muscle tension
  1. Generally loss with anesthesia
7. Other examples are a loss of blood pressure, blood color, bleeding slows or stops
Anesthetic Overdose
1. An anesthetic overdose occurs when the body saturation reaches a point that life functions start to deteriorate.
2. Signs
  1. Pulse weak
  2. Blood pressure reduced
  3. Cardiac dysrhythmias
  4. Capillary refill
  5. Respiration slow and irregular
  6. Mucous membranes pale
  7. Reflexes diminished/absent
Anesthetic Intervention
1. Once you see the signs of an overdose, stop giving the drug
2. Ventilate the animal with oxygen
3. Fluids
4. Warmth
5. Antidote
Tranquilizers & Sedatives
1. Substances that reduce anxiety and stress that an animal may experience.
2. Similar except increase dose of tranquilizer causes side effects without loss of consciousness, whereas increased doses of sedatives produce a profound CNS depression similar to anesthesia.
  1. Except for thiazine derivatives (xylazine) there is no significant analgesic activity
3. Remember, keep it simple
  1. Use a drug to do the job. If the drug does not do all you want (i.e. unconscious- ness and analgesic) then add another drug but be cautious.
  2. The two drugs are different than the individual drug.
  3. The more drugs added, the more side effects that you have to consider in your experimental design.
    1. Remember, this is not a clinical case but research
4. Uses
  1. Chemical restraint
  2. Reduce anesthetic agents
Classification of Tranquilizers
1. Phenothiazines
  1. Acetylpromazine
2. Butyrophenones
  1. Droperidol
3. Benzodiazepines‑low dose
  1. Diazepam
Classification of Sedatives
1. Barbiturates
  1. Phenobarbital
2. Benzodiazepines‑high dose
  1. Diazepam
3. Chloral derivatives
  1. Chloral hydrate
4. Thiazine derivatives
  1. Xylazine
Phenothiazine Effects
1. When using these drugs in research, one should be well aware of the side effects each drug produces.
  1. If your research is a study of hypertension, you probably should not use this drug since it will affect the study.
2. Makes animal more tractable
3. Cause hypotension & hypothermia
4. Minimally reduces respiratory rate
Butyrophenones Effects
1. Makes animal indifferent
2. Decrease motor activity
3. Cause hypotension
4. Slight increase respiration
5. Used in combination
Benzodiazepines Effects
1. Cause CNS depression
2. Mild cardiovascular depression
3. Little effect on respiration
Thiazine Effects
1. Dose‑related CNS depression
2. Little effect on respiration
3. Bradycardia, decreased cardiac output, increased central venous pressure
4. Increases susceptibility fib with halothane
5. Xylazine (Rompun)
  1. Great analgesic properties
  2. Greatly lowers body temperature
  3. Can go into ventricular fibrillation upon awaking
  4. Reversed with Yohimbine
Barbiturate Effects
1. Anesthesia
2. Not a good analgesic
3. Given intraperitoneal or intravenous
  1. Once given, not reversible
  2. May be a delayed effect
  3. If you do not wait long enough and give more, could overdose the animal
Chloral Effects
1. Reliable sedative hypnotic
2. Poor analgesic
Chloralose Effects
1. Non‑survival surgery
2. Prolonged anesthesia
3. Minimal surgical interference
4. Used for physiological studies
5. Neuro/cardio
6. Also, see ileus and hemorrhage of gut
7. Suggest it be used for minor painful procedures that are terminal.
Urethane Effects
1. Non‑survival surgery
2. Fair analgesia
3. Little effect on blood pressure and respiration
4. Cytotoxic, carcinogenic, immunosuppressive
Tribromoethanol (Avertin) Effect
1. Use only fresh solutions
2. Use only pH balanced solutions
3. Given IP
4. May cause abdominal adhesions
5. Second use can be fatal
Inhalants
1. Ether
  1. Should not be used
  2. Not the best anesthetic and extremely dangerous
2. Halothane
  1. Halothane and Isoflurane properties are about the same.
    1. Differences are that halothane is cheaper and isoflurane is almost inert in the body.
  2. Halothane is toxic to the liver
3. Isoflurane
4. Nitrous oxide
  1. Is a great analgesic but not an anesthetic
Analgesics
1. Substances that temporarily alleviate pain without causing loss of consciousness
2. Uses
  1. Used to control pain without anesthetics or pre-anesthetics and in post-op pain
3. Classifications
  1. Opioids
  2. Non‑opioids‑alpha‑2 agonists
Opioids
1. Effects CNS
2. Analgesia, sedation, respiratory depression, decreased GI motility, nausea, vomiting, etc
3. Dose varies greatly among species
4. There are reversal agents
5. Disadvantage is that most have to be given every 2-4 hours
Neuroleptanalgesics
1. Combination of narcotic and tranquilizer
2. Use up‑to‑date doses that have been determined by the combination drug
3. Fentanyl and droperidol are the combination in Innovar
4. Again, in selecting a dose, do not use the fentanyl dose and add the droperidol dose. Look up a dose for the combination.
5. Different species respond differently to the drug.
  1. Dogs and rats will respond to sound.
Other
1. NSAIDs
  1. Non-steroidal anti-inflammatory drugs such as phenylbutazone, acetaminophen, and aspirin have certain analgesic properties.
  2. Used to relieve minor pain, not visceral or major pain.
  3. Have some anti-inflammatory properties, aspirin the most.
  4. Acetaminophen is extremely toxic to the liver.
    1. Taken in combination with alcohol, can be fatal.
    2. (Most used drug in England for an overdose by humans.)
Paralytics
1. Are muscle blocking agents
2. Two basic types:
  1. Depolarizing agents - succinylcholine (not on pigs, causes malignant hyperthermia)
  2. Polarizing agents- pancuronium
Reversal
1. None for most
  1. Except for narcotics, most drugs do not have a direct reversal agent
2. Inhalants
  1. If it is a gas or infusion, turn it off.
  2. Provide 100% oxygen and ventilate if possible.
  3. (Do not give mouth-to-mouth).
3. Narcotics
  1. If it is a narcotic, give naloxone.
  2. (Naloxone has a shorter half-life than the narcotic so expect the animal to get better but in short period of time, it will go back down
4. Xylazine
  1. Can be reversed fairly rapidly with Yohimbine
5. Barbiturate
  1. Barbiturates do not have a reversal agent
  2. However, its main effect is on the respiratory center so Doxapram is a respiratory stimulant and may help
Factors Modifying Effects
1. Many factors have to be considered when using an anesthetic:
2. Species.
  1. Each species requirements are different and even some strains are different.
3. Health.
  1. All dosages are based on a healthy animal.
  2. When you have surgery, normally a blood profile is done but we do not do them on lab animals because of cost and lack of blood.
4. Route.
  1. Intravenous is the fastest.
  2. Oral is slow and unpredictable because of uptake ability, health of animal, etc.
  3. Intramuscular can cause necrosis and paralysis. Subcutaneous is least painful, slower than IM.
  4. Intraperitoneal is most used for rodents but somewhat unpredictable.
    1. Not sure where the drug went and should not "fan" the needle to see.
  5. In all cases, draw back on the syringe to ensure you are in the vein or that you are not depending on the case.
5. Amount
  1. Small animals required small doses
    1. Small doses are not very accurate
    2. You can not inject a pint of solution in the foot pad of a mouse.
6. Combination drugs
  1. Already discussed in that you use dose for combination, not single drug.
7. Handling
  1. How excited the animal is will depend on the effectiveness and predictability of the drug
    1. The more excited, the more likely the animal will not go down smoothly and when it does, it crashes
    2. Work with the animal before hand so that the animal is use to your smell and voice
Rodent Anesthesia
1. Warmth
  1. Main point, keep them at normal body temperature.
2. Airway
3. Mouse‑toe pinch
4. Rat/Guinea pig‑ear pinch
5. G pig fasted 6‑12 hours
6. Other rodents no fasting normally required
  1. They do not vomit.
7. Ketamine alone requires too high of a dose for adequate analgesic
8. IM ketamine/xylazine in hamster and some other rodents cause muscle necrosis
9. IM Innovar in G.Pig causes muscle necrosis
10. Barbiturates are poor analgesics and have high death rates, need combination for major surgery.
11. G. Pig are difficult to anesthetize (like a pig).
Rabbit
1. Rabbit very similar to rodents but somewhat more difficult
2. Respiratory center sensitive
  1. Very prone to respiratory problems during anesthesia and may require treatment afterwards
3. Trachea is very delicate
4. Pulmonary edema can occur and may require treatment
5. Rabbits have an atropinase product in them so atropine has little effect unless heavy dose given.
Swine
1. Restraint
2. Small heart
3. Ventricular fibrillation
4. Malignant hyperthermia
  1. Occurs in some breeds
  2. When given an anesthetic, they will overheat, muscles will tighten and they will die
5. Larynx
  1. Trachea has a unique bend to it
    1. If not careful when inserting an intubation tube in a young animal, you can go completely through the trachea.
Ruminants
1. Restraint
2. Sensitive to xylazine and barbiturates
3. Food withheld 24‑48 hours
  1. Need to withhold food for 24 to 48 hours because of their specialized stomach.
4. Stomach tube
  1. A ruminant not up in the normal position will die if a stomach tube is not passed.
  2. Gas builds up rapidly.
  3. Plus, you can expect to see buckets of saliva
  4. Do not use atropine to decrease saliva flow
    1. Only reduces serous secretions leaving a mucus plug that the animal can choke on
Controlled Substances
1. Controlled substances are chemicals/drugs designated by DEA as potential for abuse by humans.
2. They are identified by a capital "C" and Roman numbers (IV) on the label.
3. All controlled substances have to locked in a safe that has doubled door, attached to a wall or weigh over 2000 lbs.
  1. Nothing else can be locked in the same safe, not paperwork or drugs.
4. All controlled substances have to be purchased through Veterinary Services and registered with it
5. Every drop has to be accounted for
  1. Should match your anesthesia/surgery/post-operative report
6. Any out dated or contaminated has to be returned to Veterinary Services for shipment to Boston for destruction.
7. Examples
  1. I
  2. II
    1. Narcotics, codeine, meperidine, oxymorphone, pentobarbital, cocaine, opium
  3. III
    1. Ultra‑short barb
  4. IV
    1. Phenobarbital, methohexital, chloral hydrate, diazepam
  5. V
    1. Buprenorphine
Record Keeping
1. Lots of record keeping.
  1. As mentioned before, in governmental work, you have to have a plan (protocol), follow the plan, and then document that you did follow the plan.
2. Anesthetic records
  1. Anesthesia forms are available from Veterinary Services
    1. They are designed for individual animals undergoing surgery
    2. Rodents may be placed on "group" forms designed by the PI
      1. This is especially useful if physiological data is computer collected
    3. Requirements for form:
      1. Date, animal number (group number), weight of each animal, dose, concentration of drug, amount given, start and stop time of anesthesia, start and stop time of surgery, and how you determined that the animal was properly anesthetized throughout the experiment. (Need time intervals and measurement. i.e. toe pinch, respiration, heart rate, etc.)
    4. Records are turned into Veterinary Services no later than the next day after the animal dies or if survival surgery, maintained in the room until the animal dies.
3. Drug records
  1. Should be kept up to date at all times
  2. When the drug is used up or becomes unusable, return the records to Veterinary Services along with the bottle and any remaining drug.
Anesthesia
1. This completes the overview on anesthesia.
2. Please review your protocol and discuss the anesthesia specific for your experiment with the veterinarian at your discussion session.

Surgery

Motto of the surgeon:

To Cut is to Cure

Now we will discuss the elements of surgery.
1. We will cover Pre-operative, Operative, and Post-operative care and techniques but first, some basics
Definitions
1. Aseptic technique
  1. Not exposed to pathogenic organisms (generally means wearing sterile surgical gloves, gowns, caps, face masks, instruments, field prep.
2. Survival surgery
  1. Surgery performed on a live animal under general anesthesia, from which the animal is expected to recover
3. Nonsurvival surgery
  1. Animal is killed at the end of the surgical procedure before recovering to a level that it could experience pain
4. Major surgery
  1. Penetration of body cavity or could potentially produce a permanent handicap in an animal that is expected to recover
5. Minor surgery
  1. Restricted to the management of minor problems and injuries such as wound suturing, peripheral vessel cannulation.
6. Inflammation
  1. Cardinal signs-heat, swelling, redness, pain, itching, etc
7. Wound healing
  1. Any wound, no matter if it is“sterile” the incision/trauma has to go through stages of wound healing
    1. Inflammation
      1. This is the first stage that occurs at time of insult
      2. Depending on the amount of damage as to what extent so the surgeon needs to be aware of this and handle the tissues gently
    2. Debridement
      1. The debridement is the second stage where damaged cells are removed. Again, how the surgeon handles the tissues and creates damage will determine how long it takes for a wound to heal
    3. Proliferation
      1. This is where the cells start to multiply and fill in the gaps
    4. Maturation
      1. Maturation is the stage where all cells that are lined up correctly and are functional, remain. Others are absorbed. The whole process can take up to two years.
Inflammation

Most of the inflammation signs we see cause concern for the animal.
1. Outcome is it chews
2. Cause by
  1. Infection which we should avoid by using good technique
  2. Reaction to suture
  3. Sutures too tight which lies in poor technique by the surgeon
  4. Poor wound handling techniques (electro surgery, forceps)
  5. Dehydration.
    1. A wound left open will rapidly lose moisture since the skin is not there to protect it now
  6. In the veterinary field, we are very concerned about inflammation
    1. Any incision, no matter how aseptically done, will get inflammation
      1. This is one of the normal processes of wound healing
      2. However, the more damage done, the more reaction occurs
      3. The more reaction, the more likely the animal will destroy itself
      4. So while we are concerned about infection, our real concern is the inflammatory process
      5. Sutures too tight are the number one cause
        
        Learn to tie them correctly and allow for swelling
Regulations
1. Trained personnel
  1. In order to do surgery on animals, a person has to be trained for that species
2. Pre‑ and Post‑surgical care required
  1. Procedures with more than momentary or slight pain require analgesics
    1. If a major survival surgery is performed, then post-operative analgesics are required
  2. Records have to be documented that proper pre-operative and post-operative care was provided
Survival surgery
1. Aseptic surgical techniques
  1. Aseptic techniques is a broad term used to mean, among other things, that you use sterile instruments, sterile gloves, sterile drapes, protect the wound so that nothing can fall into it, properly disinfect an area/room, handle tissues gently with proper instruments, etc.
    1. If the surgery performed is not major, is on rodents, or in the field, you are given some leeway but still expected to do what you can to perform aseptic surgery. Requires aseptic techniques
2. Major survival surgery for non-rodents
  1. Species examples
    1. Dogs, rabbits, swine, and sheep
  2. A specifically designated area
    1. Functional areas for aseptic surgery include a separate support area, a preparation area, operating room and intensive care area
  3. Aseptic techniques including sterile drapes, sterile gowns, sterile gloves, hat, mask, and shoe covers
  4. Only items used on a regular basis can be stored in the OR
  5. Room constructed of special materials to facilitate sanitization
  6. Maintained the OR aseptic and dedicated
  7. Surgeon scrub sink out of OR
  8. Dressing area for surgeon
  9. Prep area out of OR for animal
  10. Low traffic, positive pressure, filtered air
3. Minor surgery for all species and rodent surgery
  1. Aseptic techniques requirements
    1. Sterile instruments, sterile gloves, sterile drapes, aseptic techniques
  2. Space should be an area away from traffic, no clutter or open shelves above area, and surface should be easily sanitized
4. Multiple major surgery
  1. Not allowed with out justification
  2. Requires certain restrictions which have to be discussed with the veterinarian
Non‑Survival Surgery
1. Definition
  1. Non-survival surgery is any time an animal is anesthetized and a procedure is performed that has a potential for producing more than momentary or slight pain or distress.
  2. And at the end of the experiment, the animal is euthanized without ever gaining a level of consciousness.
  3. This would be a procedure where the animal is anesthetized for a period of time, surgery or other procedures are performed that with out anesthesia, the animal would experience pain
  4. Or a procedure at the time of euthanasia that takes more than a moment and does not lead directly to death such as exsanguination or infusion of a chemical.
  5. The key word is potential for more than momentary or slight pain.
2. Record keeping
  1. An anesthetic record has to be completed and turned into Veterinary Services
Animal Preparation
1. Restraint
  1. In order to pre-op the patient, normally we have to anesthetize them
2. Hair removal.
  1. Hair is removed by a surgical clipper blade (#40 Bard-Parker) or depilatory compound (Nair) for rabbits.
  2. Remove all hair and/or compound
3. Surgical prep
  1. Povidone‑iodine scrub
    1. Prep area with povidone-iodine scrub to clean the skin
  2. 70% Alcohol
    1. Use alcohol to remove the iodine scrub and excess fat, both of which cause increased inflammation
  3. Povidone‑iodine solution
    1. Then "paint" the wound area (any area not covered by a drape) with iodine solution and wait 3 minutes.
  4. Positioning
    1. Positioning the animal to meet all requirements is next to impossible.
    2. You need the animal in a position that allows you to do proper surgery, draped so that only the prepped area is exposed and still monitor the animal for physiological factors and pain perception.
    3. One method that works well is the adhesive plastic, see-through, self adhesive drapes.
  5. Draping
    1. Cover surgery field, allow monitoring
    2. No hair should be exposed
    3. Drape should be sterile
Surgeon Preparation
1. Cap and mask
2. Hands and arms scrubbed
3. Sterile gown and gloves
4. All survival surgeries on non-rodents require
  1. The hands and arms to be scrubbed with iodine or similar soap designed for surgical preparation
  2. Put on non-sterile attire such as caps, masks, shoe covers, scrub suits, etc.
  3. Start your scrub.
  4. Dry off with a sterile towel.
  5. Put on a sterile gown (non-rodent) surgery and sterile gloves.
    1. These should be put on without contaminating them.
    2. If they are contaminated, redo.
    3. Once gloves are on, touch only sterile areas such as drapes, instruments, etc.
    4. We have a video available to demonstrate the technique of scrubbing, gowning and gloving.

Surgical Instruments
1. All instruments sterilized
  1. All instruments have to be sterilized prior to starting surgery.
  2. Autoclaving is the normal method which uses high temperatures.
  3. Chemical methods may be used with certain precautions such as realize that they are very hazardous to you and the patient (must be rinsed in sterile saline prior to use) and they have to indicate "sterilant" on the label.
    1. Alcohol is not a sterilant nor is it bactericidal. (Best used by the surgeon to drink!)
    2. Alcohol‑bactericidal, not stable, not on plastic or cement
  4. Double wrap
    1. Packs should be double wrapped with your name, date sterilized, and contents. Expiration is based on how wrapped and stored.
  5. Record keeping
    1. The autoclave has to have a test run periodically using a bacteria to test for complete sterilization.
    2. These tests and who used the autoclave has to be recorded in a log book.
  6. Re‑sterilization
    1. Do not re-autoclave packs more than once without replacing the outer wraps. (Proper autoclaving require specific pores in material which is destroyed with repeated autoclaving.)
Logistical Problem
1. Assemble all
  1. I would say that it is next to impossible to do everything correctly if you are working by yourself. First you have to assemble everything including the animal. Anesthetized it and ensure it is okay. Change into clean scrubs, open sterile packs and put out sterile materials such as sutures, knife blades, etc. Scrub and garb up. Start surgery but keep checking the animal.
2. Change into scrubs
3. Set up table, heat pad
4. Weigh, anesthetize, prep, position animal
5. Cap, mask, open packs
6. Scrub, gown, glove and drape
Suture Material
1. Definition
  1. Absorbable suture is one that loses its tensile strength within 60 days.
    1. Silk loses it tensile strength at about 65 days so it is classified as non-absorbable but in fact, it is absorbed.
2. Absorbable
  1. All absorbable sutures have to be buried within the skin, none protruding to the outside
  2. Gut
    1. Gut is an animal by-product. It is very reactive and lasts about 14-21 days
  3. Dexon, Vicryl
    1. Dexon and Vicryl are two synthetic sutures that are multifilament which means increased inflammation. They last about 7 days
  4. PDS
    1. PDS is a monofilament absorbable suture that last about 21 to 35 days
  5. Non‑absorbable
    1. Silk
      1. Silk is a natural multifilament fiber that is very reactive. As stated, it lasts about 65 days but may take up to 2 years to be fully absorbed
    2. Nylon and Prolene
      1. Nylon and Prolene are monofilament sutures that are almost equal in properties.. They are both fairly inert and last forever. Any of these sutures can be buried or outside the skin.
    3. Stainless steel
      1. Stainless steel is used in special places and for skin staples
Suture Size
1. The following diagram illustrates the relative sizes of suture. The lower the number or more zeros, the smaller the suture gets.
2. Normally, we use in dogs from 00 to 4-0, in mice and rats we use 4-0 to 5-0.

Example of a pack of sutures

Needles
1. Taper
  1. For everything but skin
2. Cutting
  1. Used only when taper won't work
  2. Reverse cutting is used
3. Curve or straight
  1. Most surgeons use the curve needle
    with the suture attached
Knots
1. Many types of knots are used in surgery, some intentional and some unintentional.
2. Square
  1. The square knot is the standard because it has less sharing force and gets tighter with more tension on it
3. Surgeon's
  1. The surgeon's knot (a double loop followed by a square knot) is the one recommended for most synthetic sutures such as Dexon, Vicryl, nylon and Prolene
4. Other
  1. Not only the way you tie (weave) a knot, but also the way you pull it down will determine the knot. If one end of the suture is held tight, then you probably tied a half-hitch (slip knot)

Suture Patterns
1. Many patterns too. However, with animals, 99% of the time you will only use an interrupted pattern.
2. Interrupted
  1. This pattern is less likely to run an infection the whole length of the incision line.
  2. It also is safer if the animal decides to remove the sutures for you. With a continuous pattern, a break anywhere and all the sutures come out.

Continuous

Inverting
1. Used to close the bladder or intestine where the lumen is
  contaminated. See diagram on the right.

Everting
1. This pattern is rarely used today. It was used to roll the
  skin out. See diagram on the left.

Appositional
1. This pattern is the one used with interrupted pattern
  where the skin epithelial layer perfectly lines up so that they are straight across.

Surgical Techniques
1. Surgical techniques are probably the most important part of surgery because it is where you bring all the parts together for a successful outcome.

The above chart demonstrates several points:
1. The top two demonstrates how the outer surface should come together perfectly and how, theoretically, the suture should go through the skin.
2. The rest indicate problems associated with too tight sutures. This is the number one cause of too much inflammatory reaction leading to the animal pulling out the sutures. The very bottom diagram shows the sutures “lying” on the skin, not being pulled down. The one above it shows sutures too tight and “digging in” forming a corrugated surface. Put the sutures in so that the skin just kisses. If the skin does not come together, put in more sutures, not pull tighter.

Complications
1. Hypothermia
  1. Biggest complication is allowing the body core temperature to fall below normal.
    1. This can have profound effect on anesthesia and recovery.
  2. Use water circulating heat blanket or a heat light. (Albino animals lack pigmentation in their retina so bright lights hurt their eyes, cover them.)
2. Dehydration
  1. Dehydration occurs as soon as the skin is broken. Keep the edges moist.
3. Hemorrhage
  1. Hemorrhage is not a big problem. However, animals only have a small amount of blood and if they bleed too much, they are dead.
4. Anesthetic overdose
  1. Anesthetic overdose has already been discussed.
5. Dehiscence
  1. Dehiscence occurs generally associated with too tight sutures and the animal chews them out and then the guts fall out.
6. Dead space ("Pockets")
  1. When closing a wound, make sure all dead space is closed. Open space between layers leaves a "pocket" for fluid formation. This is a perfect place for an infection to occur or cause a dehiscence. At the least, it will cause a delay in healing. Use sutures to "tack" down the layers removing any dead space.
7. Inflammation/infection
  1. Inflammation will occur. Try to keep it to a minimum.
  2. Infections should not occur.
8. Recheck your sutures and make sure they are not too tight.
  1. Re-evaluate them the next two days and make notes. Then when you do the next case, adjust.
Post‑Operative Care

A. Now that you have completed surgery, you must first recover the animal from anesthesia and then care for wound and the animal through the post-operative period

B. Trained personnel

a. Must be trained.

b. If not, how do you judge progress and give proper care?

c. It requires training from others and you training yourself to observe and connect signs observed with possible outcomes.

C. Warm, quiet, clean, rotated

a. During initial recovery, warmth is very important.

b. The animal has to be turned from side to side about every 10 minutes to prevent hypostatic pneumonia.

D. Fluids, special care

a. Monitor the patient closely for replacement fluid needs

E. Analgesics

a. Analgesics are required if major surgery.

i. It says several doses, which according to the dictionary, several means 3 or more.

b. The first dose should be given prior to the animal reaching a state of consciousness that it could experience pain.

c. If buprenorphine is used (the only drug found to work up to 12 hours), then the next dose is within 12 hours. It could be within 4 hours but can not go longer than 12 hours.

i. Normally it is given at 8 PM and again at 8 AM and finally, at 8 PM.

d. Remember the dose stated is for a normal, healthy animal.

i. An animal just out of surgery is not normal and probably not healthy so reduce the dose. The effect we want is primarily out of pain but also we want an alert, eating and drinking animal. Adjust dosage appropriately according to condition and signs.

F. Antibiotics

a. Antibiotics should not be given without veterinary approval unless already approved in protocol.

b. For surgery, antibiotics, when given, should be given prior to cutting so the tissue levels are saturated with the drug.

Wound Care
1. Inflammation
  1. Wound care involves checking daily for inflammation/infection.
  2. Know how to recognize the signs and what act should be taken.
    1. In all cases, notify the veterinarian for any unexpected problems.
2. Infection
  1. Starts off as increased inflammation with redness, swelling and later drainage
3. Special wound care
  1. Certain types of surgery require additional care which should be stated in the protocol and should be followed. Record all care in the records.
4. Sutures
  1. Sutures have to come out unless specifically justified in protocol, animal dies within 14 days, or they are absorbable and buried.
    1. Normally, they come out at 7 days.
5. Reports
  1. A post-operative report is required each post-operative day until the wound heals, normally at 7 days when the sutures come out.
  2. It is done as a "SOAP".
    1. "S" is for subjective -- how you feel the animal is doing.
    2. "O" is for objective -- signs observed such as walking, eating, drinking, etc.
    3. "A" is for assessment. State how the animal is progressing.
      1. Do not say the animal is doing great when it is walking on three legs. What you might mean is that the animal is progressing normally.
    4. “P” is for plan—how do you plan to progress, what’s next
In summary
1. Lots to do to get ready to do surgery, then hard to give an anesthetic, do the surgery, and all the reports.
2. But it all leads up to what is required after anesthesia/surgery.
3. Everything done correctly will mean an easy recovery leading to acceptable results.
4. But don't quit at the end of surgery. Be just as diligent in your post-operative care.
Record Keeping
1. Protocol
  1. Protocols are written, approved by the IACUC and must be followed.
2. Anesthesia records are required any time you do anesthesia even for a short, quick procedure.
3. Surgery reports are required for any surgery done, survival or non-survival.
4. Post-operative reports are required until the animal recovers, normally at suture removal.
5. All records stay with the animal in its holding room until it dies or is adopted then they are filed in Veterinary Services.
  1. Anesthesia and surgery records are due in the folder no later than the next working day, if not sooner.
Summary
1. This concludes the didactic portion of the surgery training. A meeting with the veterinarian is required to complete the course. At the meeting, bring your protocol and be prepared to discuss your role in anesthesia, surgery, and recovery.

Please complete the review so that we have a record of you taking this course. Thank you.
Click here.