Lecture 2, principles of surgical asepsis

Question 1

Infection

Answer 1

Invasion and multiplication of microorganisms (bacteria, virus, parasite) that aren’t normally present at the site.

Potentially devastating and challenging complication of surgery.

In hospital settings, transmission of microorganisms is most commonly contact-related.

All possible measures should be taken to reduce the risk of iatrogenic infection.

Question 2

Sterile technique (6)

Answer 2

1. Sterile personnel are gowned and gloved.
2. Sterile personnel touch only sterile items/areas.
3. Sterile drapes are used to create a sterile field.
4. Use only sterile items within sterile field.
5. Sterile items should be opened, dispensed and transferred by methods that maintain sterility.
6. The field should be monitored constantly and the surgical staff should be able to recognise when they have broken technique and act accordingly.

Question 3

General rules of aseptic technique (7)

Answer 3

1. Surgical team members remain within the sterile area
2. Talking and movement by all personnel is kept to a minimum
3. Nonscrubbed personnel touch only nonsterile items and do not reach over sterile areas
4. Drapes should be moisture proof
5. If the surgical team begins the surgery seated, they should remain seated until it has been completed
6. Gowns are considered sterile only from mid-chest to waist and from gloved hand to 5 cm above the elbow
7. Items of questionable sterility are considered contaminated

Question 4

Critical level of sterility (and disinfection)

Answer 4

Equipment/materials entering the body beneath the skin or mucous membranes require sterilization and are handled using sterile technique,
e.g. suture materials, intravenous catheters

Question 5

Semicritical level of disinfection

Answer 5

Equipment coming into contact with skin/mucous membranes without penetration must be cleaned and disinfected,
e.g. endotracheal tubes.

Question 6

Noncritical level of disinfection

Answer 6

Instruments that contact the mucous membranes or intact skin not directly associated with surgery should be cleaned and disinfected,
e.g. laryngoscope.

Question 7

Preparation of surgical packs (6)

Answer 7

1. Instruments and linens must be cleaned of gross contamination
2. Instruments cleaned manually or with ultrasonic cleaning equipment
3. Linens laundered
4. As soon as possible after surge
5. Immersing instruments for long periods of time in any solution can prove damaging (never longer than 20min)
6. Cleaning is followed by packaging and sterilization

Question 8

Sterilization methods

Answer 8

Steam

Chemicals

Plasma

Ionizing radiation

Cold chemical sterilization

Question 9

Steam sterilization

Answer 9

Destroys all known microorganisms by coagulation and cellular protein denaturation.

Practical and dependable.

Heat-tolerant medical supplies and packaging.

Autoclave:
- Gravity displacement sterilizer (15-30min at 121C)
- Prevacuum sterilizer (3-4min at 132-135C)

Question 10

Sterilization indicators

Answer 10

Allow monitoring of the effectiveness of sterilization.

Indicators may undergo chemical or biological change in response to time and temperature. Not always trustworthy.

Question 11

Failure to achieve sterility may be a result of

Answer 11

Improper cleaning

Mechanical failure

Improper use of equipment

Poor loading technique

Not understanding the concepts of sterilization

Question 12

Preparation of operative site

Answer 12

Preoperative preparation reduces the number of bacteria and the likelihood of infection.

Sterilizing skin without impairing its natural protective function and interfering with wound healing is impossible.

ANTISEPSIS!

Question 13

Preparation of patient

Answer 13

Treatment of any infections if elective surgery

Dietary restrictions

Excretions

Confirmation of the patient’s identity, the surgical procedure and surgical site

Treatment of hair

Question 14

Removal of hair

Answer 14

Immediately before surgery (infection risk)!

Outside the operating theatre

Clipping initially done with the hair growth pattern, then against

Loose hair removal

Prepared area should be large enough to accomodate extension of the incision (20cm on each side of the incision)

Paws can be excluded from the surgical area by placing a latex glove over the distal extremity and covering it with self-adherent bandaging tape

Question 15

General cleansing rub

Answer 15

Prepuce is flushed with antiseptic solution in case of abdominal procedures in male dogs

Skin is rubbed with germicidal soaps and warm water to remove debris and reduce bacterial populations

Incision site -> moving from the center to the periphery
Exceptions: infected wounds, abscess

Untill all dirt and oils have been removed

Antiseptic is applied

Question 16

“Sterile” skin preparation

Answer 16

Should be done after positioning the patient

Purpose:
- to remove soil and transient microorganisms
- to reduce resident microbial count to subpathogenic levels with the least amount of tissue irritation
- to inhibit rapid rebound growth of microorganisms

Aseptic technique:
- antiseptics are used (chlorhexidine gluconate > povidone-iodine?)
- gloved hands
- avoid contaminating sponges/gauze swabs
- from the center to periphery, the discard

Question 17

Draping (6)

Answer 17

1. Creating and maintaining a sterile field around the operative site with non-absorbant towels
2. Performed by a gowned team member when antiseptics have dried
3. One at the time
4. Drapes shouldn’t be flipped or shaken
5. Once placed, shouldn’t be readjusted
6. After the animal and nearby nonsterile surfaces have been covered with sterile drapes, the instrument tray can be arranged, and surgery can begin