Aseptic Technique, Surgical
Support and Anesthesia
LAT Chapter 11
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Chapter 11
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Introduction
Chapter 11
• Many minor procedures
use aseptic technique in a
clean environment, such as
a research laboratory.
• Other procedures require a
dedicated surgery room
similar to that used for
human patients.
Aseptic Technique
Chapter 11
• Contamination = introduction of pathogenic organisms
• A disinfected or sterile area = a field
 disinfecting the field with chemical solution + manipulating sterile
instruments to avoid touching contaminated surfaces
 field = surgery site and adjacent areas, surgery table, area where
instruments will be placed or inside of laminar flow hood
 requires specialized knowledge and careful attention to detail
• To prevent contamination, so healing => without infection.
• Initial procedures:
 preparation of surgical team, operating room, instruments, patient
• During procedures:
 Contact of a sterile surface with other surfaces avoided.
 Like a chain, only as strong as its weakest link.
A Disinfected or Sterile Area
Chapter 11
A Disinfected or Sterile Area
Chapter 11
A Disinfected or Sterile Area
Chapter 11
A Disinfected or Sterile Area
Chapter 11
Aseptic Technique (continued)
Chapter 11
• Required for all vertebrate animals which are to recover.
 Survival surgery on the smaller laboratory animals performed in a
sanitized lab area, with appropriate aseptic technique.
 A dedicated surgery required for non-rodent mammals.
 Major surgery = entering a body cavity or causing permanent
post-surgical disability.
• Contamination prevention procedures:
1. Cleansing and disinfection of operating room
2. Preparation of incision site and draping the animal
3. Aseptic preparation of the surgical team
4. Sterilization of surgical instruments and materials
• Prevention also includes responsibility of surgeon.
 gentle handling of tissue and proper suturing technique
Aseptic Technique (continued)
Chapter 11
Preparation of the
incision site and
draping the animal.
Maintaining Sterility
Chapter 11
• Other precautions for maintaining a sterile field are:
1. Never turn backs on a sterile surface.
2. An unsterile area not touched or leaned over.
3. Sterile instruments never be below the edge of the surgical table.
4. Arms and hands remain above the waist and below the shoulder.
5. Lift up materials, do not drag over edges of containers.
6. Keep all sterile surfaces dry.
7. Avoid excessive movement during surgery.
8. Avoid shaking of gowns, towels, drapes, and other materials.
9. Keep conversation to a minimum during surgery.
10. If waiting, clasp hands in front of your body above the waist.
• If contamination occurs during any part of the procedure,
stop and correct the situation immediately.
Maintaining Sterility
Chapter 11
Sanitation
Chapter 11
• Sterility and Asepsis: Sterility = state in which there are
no living microorganisms present. Asepsis = state in
which the number of disease-producing microorganisms
(pathogens) have been greatly reduced.
• Antiseptics: substances that destroy or inhibit the growth
of microorganisms, but do not sterilize the area, and can
be used on living tissue
• Disinfectants: destroy or inhibit the growth of
microorganisms, but do not sterilize, usually damaging to
living tissue
• Contamination: the process by which something is
rendered unclean or non-sterile
Pre-surgical Care of Patient
Chapter 11
• Special care aids the well-being of the animals and
contributes to the success of the operation.
• Food may be withheld before surgery (6–8 hours,
depending on the species) to reduce the chance that the
animal may vomit while anesthetized.
• Sometimes an enema or laxative will be given, in addition
to withholding food, to empty the contents of the lower
intestinal tract prior to intestinal surgery.
• Perform physical exam before surgery.
 Specimens of blood and urine may be taken
to help determine the animal’s state of health.
Patient Preparation
Chapter 11
Patient prep. includes the following steps:
1. Clip a broad area around site being careful
not to cut the skin.
2. Scrub area with surgical soap for five min.
• Start at center of the site and work outward in larger and larger
circles. Every time you go back to the center, use a new piece of
gauze and start again.
3. Wipe area with sterile gauze sponge, starting at the center of the
site, until all the surgical scrub material is gone.
4. Some surgeons follow the scrub with 70 percent ethyl alcohol.
5. Sterile surgical drapes are placed around the incision site, only
people wearing sterile surgical gloves should touch the site.
6. Particularly dirty animals require bathing prior to surgical prep.
Surgical Personnel Preparation
Chapter 11
Scrubbing:
1- Don a mask and cap.
2- Scrubbing done with a surgical hand brush and soap.
3- Apply soap to hands and arms, lathering without brush.
4- Rinse - elevate hands above the level of elbows, so that rinse
water runs off the elbows, not back over hands.
5- Reapply soap and scrub hands and arms with brush.
6- Scrub from hands to elbows so cleanest area is hands.
• Each finger = > 10 strokes on each surface (40 strokes / finger)
• Fingernails and both surfaces of hands = 20 strokes each
• Each arms surface = 10 strokes
7- Rinse in warm water, allowing the water to drip from the elbows.
8- Repeat entire scrubbing procedure twice.
Surgical Personnel Preparation
Chapter 11
Drying, Gowning & Gloving
Chapter 11
• Pick up sterile towel by 1 end using 1 hand.
 Dry fingers and hand of the opposite arm, then dry arm to elbow.
 Grasping opposite end of towel with dry hand, repeat.
 Once towel is used on arms, don’t use on hands or fingers.
• Unscrubbed assistant opens gown pack outer wrapping.
 Scrubbed surgeon grasps folded gown at the shoulder.
 Places the left arm into the sleeve, right arm into the sleeve.
 Assistant grasps inside of gown and pull the sleeves into place.
• grasps the inside of the gown and pull down to straighten the front
• ties the neck and waist
• assistant opens glove pack
• Left pick up right glove rolled cuff, pull over the right...
• Throughout gowning and gloving procedures, bare fingers should
never touch any part of gown or any part of outside of gloves.
Gowning
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Chapter 11
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gowning
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Chapter 11
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gowning
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Chapter 11
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gowning
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Chapter 11
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Gloving
Chapter 11
Images courtesy of:
Copyright 1995-1998 Trustees of the University of Pennsylvania
Principles of Surgery
Go to - http://cal.vet.upenn.edu/surgery/
Surgical Instruments I
Chapter 11
• Forceps: for compressing or grasping tissue. Thumb
forceps and hemostats are typical forceps. Hemostats aid
in compressing tissue, especially blood vessels, to stop
bleeding (hemostasis).
• Needle holders: hemostat-like devices that hold needles
used to suture wounds closed.
• Needles: permanently attached suture material =
swaged-on. Tip may be blunt, tapered, sharp, cutting, or
some other configuration
• Scalpel handle and blades: size 10 blade most popular,
11 has a straight edge and a sharp point.15 has a very
small cutting edge, used for fine, delicate surgery(e.g.
eye). 20 is similar to 10 but larger.
Surgical Instruments II
Chapter 11
• Scissors: blunt-blunt, blunt-sharp, or sharp-sharp. They
may also be straight or curved. Some scissors are
serrated for cutting thick bandages or cartilage.
• Retractors: pull overlying tissue away from the surgical
site. Hand-held retractors and self-retaining
• Suture materials: thickest suture is given the number 6.
• <6 = smaller diameter.
• Sutures having smaller diameter indicated by 0 (“aught”) smallest
suture is designated 12-0 (twelve-aught).
• Synthetic = nylon, or natural = silk or gut.
• Some absorbed by the body during the healing process, nylon
removed after wound heals, usually in 7–10 days.
• Gauze pads: sponges used for soaking up blood and
other fluids from the surgical site.
Cleaning Surgical Instruments
Chapter 11
Manual Cleaning:
1. Rinse instruments in cold water ASAP.
2. Open all locks and disassemble instruments.
3. Inspect each instrument, for proper function
and cleanliness.
4. Scrub each instrument.
5. Rinse instruments with hot, clear water.
6. Dry thoroughly before re-packing.
Ultrasonic Cleaning: converts high frequency sound waves
into mechanical vibrations.
 Removes ~ 90 % of the dirt and debris but does not sterilize or
eliminate the need for initial removal of blood and dirt.
Lubrication: After cleaning but before autoclaving, use only
antimicrobial, water-soluble lubricants.
Sterilizing Surgical Materials
Chapter 11
• Chemical sterilization, “cold” sterilization, reserved for
surgical instruments and other items that are heatsensitive and can be immersed in liquid.
 Glutaraldehyde requires 10 hrs to sterilize instruments.
 Very irritating to tissues, rinse off thoroughly with sterile saline.
• Ethylene oxide requires chamber with vent to the outside
 Very toxic gas; items must “air out” for a minimum of 24 hours
after procedure to prevent exposure.
 Plasma vapor autoclave utilizes non-toxic hydrogen peroxide to
sterilize heat-sensitive items.
• Dry heat sterilization in an oven or glass bead sterilizer.
 Small glass beads are super-heated in a stainless steel chamber.
Instruments sterilized within 10 seconds.
Cleaning Surgical Instruments
Chapter 11
Glass Bead Sterilization
Cold Sterilization
Autoclave Sterilization
Chapter 11
1. Soak gowns, drapes and launder.
2. Pack materials by procedure and surgeon’s preference.
3. Don’t densely pack.
4. Pack and wrap to allow opening without contaminating.
5. Color change occurs on the indicator in the center of the
pack If that location reached 121°C for 15 minutes.
6. Label packs on the outside with date sterilized.
• Packs correctly wrapped remain sterile for up to six
months if they’re stored properly and remain dry and
sealed.
 Wetness destroys the effectiveness of the wrapper as a
contamination barrier.
Autoclave Sterilization
Chapter 11
Anesthesia
Chapter 11
• Local - Xylocaine (Lidocaine®) and bupivicaine
(Marcaine®) injection examples
 Topical liquids, sprays, ointments, or creams. Proparacaine
(Ophthaine®), anesthetic eye drops
• General injection = barbiturates (thiopental and
pentobarbital) and ketamine.
 Ketamine used to immobilize nonhuman primates
 Poor analgesia and muscle relaxation, combined with analgesic
• Anesthesia can be maintained in small rodents using a
plastic syringe case as a nose cone.
 Use under a certified fume hood that prevents the breathing of
anesthetic gas by the person doing the procedure.
 Gas anesthetics include halothane and isoflurane. Isoflurane
produces rapid anesthesia and rapid recovery, and is often used
in short procedures such as blood collection in rodents.
Anesthesia
Chapter 11
Monitoring Anesthetized Patient
Chapter 11
• Vital signs - color of mucous membranes,capillary refill
time, heart, pulse, respiratory rate and respiratory depth
 Color of the foot pads (perfusion) used as an indicator of adequate
blood circulation.
• BP, EKG or ECG & blood gas
• Frequent measurement of body temp.
 General anesthetics can cause hypothermia.
 Place on warm surface to prevent hypothermia.
• Monitor to determine that animal is adequately
anesthetized.
 Too deep = close to death, insufficient = feeling pain.
 If the animal withdraws the foot when it is pinched, then the surgery
or painful procedure must be delayed until proper anesthesia is
achieved.
Post-surgical Care of Patient
Chapter 11
• If still unconscious, turn from side to side frequently to
prevent blood pooling in tissues of the down side.
• Waking animals => involuntary and uncontrolled motions.
 Place by itself in a recovery cage, food and water bowls removed.
 Be aware behavior during recovering is not like conscious animal.
 Be on the alert for complications that endanger life or well-being.
• It is crucial that all medications be given in the correct
dose and at the designated time intervals.
• Keep veterinarian aware of how treatments are
progressing. Veterinarian may decide to change the
treatment. Technicians should not make these decisions.
Post-surgical Care of Patient
Chapter 11
Assessing Pain & Distress
Chapter 11
• Pain perception results from stimulation of specialized
nerve endings in the tissues.
 Impulses from these nerve endings reach the cerebral cortex
through specific nerve pathways.
 Pain sensation => withdraw from noxious stimuli => protective.
 Local anesthesia, nerve pathways blocked, no pain perceived.
 General anesthesia, loss of consciousness, pain perception in
cerebral cortex not functioning.
• Stress from physiologic, psychologic, environmental or
physical factors which alter normal state of homeostasis.
 distress => physiological changes, difficult to observe
• Acute = short and often severe / Chronic = longer time
• Pain to humans is assumed pain to other species.
Acute Pain
Chapter 11
Guarding
Crying
Self-mutilation
Restlessness
Sweating
Panting
Tooth grinding
Recumbency
Ambulation
Abnormal postures
Chronic Pain
Chapter 11
1. Limping or carrying a limb
2. Licking or rubbing an area of the body
3. Reluctance to rise and move
4. Loss of appetite
5. Change in temperament or behavior toward handlers
6. Change in bowel and/or urinary activity
7. A lack of self-grooming
 analgesic drugs - acetaminophen (Tylenol®) buprenorphine and
the non-steroidal anti-inflammatory drugs (NSAID) like aspirin
and ibuprofen.
• Analgesic reduces pain sensation. Tranquilizer diminishes anxiety.
 The most important component of pain or distress control is
ability of technician to recognize and assess abnormal behavior.
Chapter 11
Additional Reading
Chapter 11
1. Flecknell, P.A. Laboratory Animal Anesthesia, 2nd Ed.
Academic Press, San Diego, CA, 1996.
2. Knecht, C.D. et al. Fundamental Techniques in Veterinary
Surgery, 3rd Ed. W.B. Saunders, Philadelphia, PA, 1987.
3. Short, C.E., ed. Principles and Practice of Veterinary
Anesthesia. Williams and Wilkins, Baltimore, MA, 1987.
4. Recognition and Alleviation of Pain and Distress in
Laboratory Animals. National Academy Press,
Washington, D.C., 1992.