Haemostasis and asepsis

Question 1

Give definitions of the following:

1. antisepsis
2. disinfection
3. sterilisation

Answer 1

1. Use of germicide substances on living tissue
2. Use of germicide substance on an inanimate object
3. the process of destroying all microorganisms

Question 2

What is a nosocomial infection?

Answer 2

Hospital-acquired infections, often caused by highly antibacterial-resistant strains of bacteria

Question 3

What is a surgical infection defined as?

Answer 3

An infection developing at the site of surgery within 30 days of surgery (1 year if an implant has been placed). May be part of the disease being treated (e.g. traumatic wounds, abscesses, infected joints) or may be a result of the surgery performed (e.g. osteomyelitis after fracture repair)

Question 4

Compare prophylactic and therapeutic antibacterial

Answer 4

Prophylactic - Those given before bacterial contamination has occurred.
Therapeutic - Those given to treat an existing infection.

Question 5

How can pressure be used as a haemostatic technique?

Answer 5

• From small vessels e.g. capillary ooze
• Apply a moist swab for up to 5 minutes – avoid disturbing the clot (Time it!)
• Dab don’t wipe

Question 6

When are haemostatic forceps used as a haemostatic technique?

Answer 6

Use the smallest forceps suitable to crush the vessel and physically occlude it, allowing clot formation to take place.
Can only be used on vessels that are to be sacrificed and not repaired

Question 7

What are the 2 clamping methods of using haemostatic forceps?

Answer 7

• Tip clamping: to occlude small vessels

- Jaw clamping: to occlude larger vessels

Question 8

How do radiofrequency instruments work as a haemostatic technique?

Answer 8

Use an electric current to coagulate tissue and cause vessel thrombosis

Question 9

Compare monopolar and bipolar cautery

Answer 9

Monopolar - Current flows from a single hand electrode to a ground plate placed under the patient.
Bipolar - Current flows between the two sides of a hand-held forceps

Question 10

Which is better, monopolar or bipolar cautery and why?

Answer 10

Bipolar

- More precise, requires less current and works better in a wet surgical field than monopolar

Question 11

Give 2 example of vessel sealing devices

Answer 11

• Electrothermal bipolar vessel sealers

- Harmonic scalpels

Question 12

What is the best haemostatic technique for large vessels?

Answer 12

Ligatures to occlude the vessel

Question 13

What two types of ligatures can be used to occlude larger vessels?

Answer 13

• Circumferential

- Transfixing

Question 14

What are vascular clips used for?

Answer 14

Metal or absorbable polymer vascular clips mounted on single or multiple-use applicators are rapid, convenient but costlier than ligatures.

Question 15

How do you ensure that vascular clips have permanently occluded a vessel?

Answer 15

• Remove as much surrounding tissue as possible before application.
• The vessel diameter should be greater than 1/3 and less than 2/3 the length of the clip.
• Apply the clip several mm from the end of the vessel.
• Clip arteries and veins separately.
• Use multiple clips on arteries and larger veins

Question 16

Give examples of causes of wound infection during surgery

Answer 16

• clipping the surgical site
• anaesthesia and surgery time (risk of infection doubles every hour)
• Number of people in the operating room

Question 17

How can Propofol use increase the chance of a wound infection?

Answer 17

Propofol is suspended in a lipid-based emulsion that can support bacterial growth

Question 18

How can a patients sex increase the chance of a wound infection?

Answer 18

Male animals are at increased risk of wound infection due to the immunomodulatory effects of androgens

Question 19

Normal tissue responses to infection can be compromised by which factors?

Answer 19

• Trauma
• Foreign material
• Ischaemia due to shock or trauma
• Poor nutrition
• Chemotherapy
• Systemic disease

Question 20

What are some examples of endogenous sources of bacterial contamination?

Answer 20

Sources from the patient: skin, respiratory tract, GI tract

Question 21

What are some examples of exogenous sources of bacterial contamination?

Answer 21

From outside the patient: room air, surgical team, instruments, drapes

Question 22

How can patient selection and preparation prevent surgical infections?

Answer 22

• Postpone surgery in patients with pre-existing disease until it is resolved
• Clip the surgical site just before surgery: clipping before anaesthesia or shaving the site both increase postoperative infection rates.
• Thoroughly clean the surgical site with chlorhexidine or povidone-iodine based skin prep solution.
• Use surgical drapes: waterproof drapes reduce strikethrough and bacterial wicking

Question 23

How should the surgical team and equipment be prepared to prevent surgical infections?

Answer 23

• Preoperative hand rub with an alcohol-based solution or a 3-5 minute preoperative hand scrub with antiseptic soap e.g. chlorhexidine.
• Wear sterile surgical gloves and gown
• Scrub suits and surgical masks
• Sterilise all equipment

Question 24

What should be used to check equipment has been sterilised?

Answer 24

Biological indicators (glass vials containing heat-resistant bacteria)

Question 25

How should the operating theatre be prepared to reduce surgical infections?

Answer 25

• Disinfect all surfaces daily.
• Disinfect the operating table between procedures.
• Don’t prepare patients for surgery in theatre or store equipment in there.
• Keep the number of people in theatre to a minimum.
• Keep traffic through theatre to a minimum

Question 26

What features of a wound need to be monitored post operatively?

Answer 26

• Heat
• Pain
• Redness
• Swelling
• Discharge