Surgery Flashcards
Sepsis
Presence of pathogens
Asepsis
Free from infection
Antisepsis
Prevention of sepsis
Sterilisation
Elimination of all microorganisms including spores
Disinfection
Removal of all microorganisms, sometimes not including spores.
Bacterial infection
defined as having more than 10^5 bacteria per gram of tissue i.e. bigger than colonisation.
Classification of surgical wounds
- Clean
- Clean-contaminated
- Contaminated
- Dirty
Clean wound
Non-traumatic, non-inflamed operative wounds that do not enter respiratory, gastrointestinal, urogenital, oropharyngeal tracts.
E.g. elective neuter, THR
Infection rates = 0-4.4%
Clean-contaminated wound
Operative wounds in which respiratory, gastrointestinal, urogenital, oropharyngeal tracts are entered but under controlled conditions without unusual contamination.
E.g. bronchoscopy, enterotomy
Infection rates =4.5-9.3%
Contaminated wound
Open, fresh, accidental wounds or procedures in which GI contents or infected urine is spilled or a major break in aseptic technique occurs.
E.g. cystotomy with spillage of infected urine, open cardiac massage for CPR
Infection rates =5.8-28.6%
Dirty wound
Old traumatic wounds with purulent discharge, devitalised tissues or foreign bodies; procedures in which a viscus is perforated or faecal contamination occurs.
E.g. excision/drainage of an abscess, bullae osteotomy for otitis media, perforated intestinal tract
Gross infection is present
Circumstances in which antibiotics should be used prophylactically
- Surgery time longer than 90 mins
- Prosthesis implantation E.g. mesh, pacemaker, bone cement
- Patients with pre-existing prosthesis E.g. hip replacement undergoing certain surgical procedures
- Severely infected or traumatised wounds
Factors affecting the establishment of infection
- Host factors e.g. age, physical condition, nutritional status etc.
- Diagnostic procedures e.g. placing a catheter increases likelihood of an ascending infection
- Concurrent metabolic disorders e.g. HAC
- Medication e.g. corticosteroids, chemotherapy
- Operating room practice
- Aseptic technique
- Sterilisation, disinfection
- Anaesthesia
- Atraumatic technique
- Characteristics of bacterial contaminants
Discuss the rational use of antibiotics in the surgical patient
- Generally, antibiotics are used for contaminated/dirty wounds
- Sometimes they are used for clean-contaminated wounds
- Prophylactic use is rarely recommended, but may be indicated in specific circumstances
- Rational selection of antibiotics should be used
- Ideally this would depend on culture and sensitivity, but in practice time and financial constraints mean this isn’t possible
Give an example of an antibiotic that could be used for a patient undergoing large intestine surgery
- In this case we might be particularly concerned about anaerobes
- Metronidazole has good anaerobe coverage
Which should you use for cutting skin: scissors or a scalpel?
A scalpel
Scissors = poor practice, would crush the skin as they cut.
What is the most commonly used scalpel blade?
Number 10
Which scalpel blade should you use for the most delicate tissues? e.g. a urethrostomy
Number 15
Which forceps are considered the go-to for soft tissue surgery?
Debakey forceps
They were originally designed for vascular use and are the least traumatic of forceps
Here are some forceps. What are they used for?
Haemostat forceps
- Designed to occlude blood vessels and prevent haemorrhage
Here are some forceps. What are they used for?
Tissue holding forceps
- Designed to handle and manipulate tissues.
- Specific design varies according to relevant tissue.
Tensile strength
breaking strength per unit area.
i.e. how strong it is under tension
Memory
tendency to retain original configuration when it comes out of the packet.
Which has higher memory: monofilaments or multifilament? What does this mean?
Monofilaments have higher memory, making it potentially harder to tie secure knots.
Chatter/tissue drag
lack of smoothness/friction while passing through the tissue.
Multifilaments have more drag than monofilaments.
Tissue reaction
inflammatory response to the placement of sutures
What are the advantages of absorbable suture material?
✅ They disappear
✅ Low risk of long-term foreign body reaction
What are the disadvantages of absorbable suture materials?
❌ Lose strength
❌ Limited period of wound support
What are the advantages of non-absorbable suture materials?
✅ Permanent
✅ Provide indefinite wound support
What are the disadvantages of non-absorbable suture materials?
❌ They do not disappear
❌ Possibility of delayed reactions e.g. foreign body reaction
What are the advantages of braided (multifilament) suture materials?
✅ Easy to handle
✅ Excellent knotting; very secure
What are the disadvantages of braided (multifilament) suture materials?
❌ Greater friction and tissue drag
❌ More tissue trauma
What are the advantages of monofilament suture materials?
✅ Minimal tissue trauma
✅ Passes through tissues easily: minimal drag
✅ No capillary action
What are the disadvantages of monofilament suture materials?
❌ Harder to handle
❌ Harder to knot
❌ Require different knotting technique for greater security
What are the advantages of natural suture materials?
✅ Easy to handle
✅ Easy to knot compared to synthetic monofilament sutures
✅ High histocompatibility
What are the disadvantages of natural suture materials?
❌ Moderate/high tissue reaction
❌ Low tensile strength
What are the advantages of synthetic suture materials?
✅ High tensile strength
✅ Predictable biological behaviour
What are the disadvantages of synthetic suture materials?
❌ Poorer knotting than natural materials (if synthetic monofilament)
What are the consequences of suture material implantation?
- Suture material is a foreign body which causes a tissue reaction
- Methods of absorption:
- Phagocytosis - more aggressive
- Hydrolysis - generally smaller tissue reaction
- Phagocytosis - more aggressive
What are the consequences of suture material implantation?
- Suture material is a foreign body which causes a tissue reaction
- Methods of absorption:
- Phagocytosis - more aggressive
- Hydrolysis - generally smaller tissue reaction
How are natural sutures absorbed?
via phagocytosis
e.g. catgut
How are synthetic sutures absorbed?
Hydrolysis
If there is infection in a wound, are you better off closing it with monofilament or multifilament?
Monofilament
Multifilament has a large surface area and provides nooks and crannies for bacteria to colonise
What size suture material would we use for ophthalmic surgery?
11-0
What are some issues with eyed needles?
❌ Have to use a double strand of suture material → increased tissue trauma
❌ Multiple uses will blunt the needle
Why are swaged needles the needles of choice?
✅ Cause minimal trauma
✅ Single use
✅ Optimal penetration properties
However, they are more expensive
When would we use a taperpoint needle?
When suturing the intestines (where we don’t want to make a big hole)
What is ductility?
Ductility: the bending property of the needle. It warns the surgeon that the force being placed upon it is too great.
Name some prophylactic antibiotics you could give to an equine patient undergoing surgery (if antibiotics were required).
- Procaine penicillin (IV)
- Gentamicin (IV)
- Oxytetracycline (non IV)
How should theatre be cleaned at the start of the day?
Damp dust with disinfectant
