Haemostasis and asepsis Flashcards
Give definitions of the following:
- antisepsis
- disinfection
- sterilisation
- Use of germicide substances on living tissue
- Use of germicide substance on an inanimate object
- the process of destroying all microorganisms
What is a nosocomial infection?
Hospital-acquired infections, often caused by highly antibacterial-resistant strains of bacteria
What is a surgical infection defined as?
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)
Compare prophylactic and therapeutic antibacterial
Prophylactic - Those given before bacterial contamination has occurred.
Therapeutic - Those given to treat an existing infection.
How can pressure be used as a haemostatic technique?
- 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
When are haemostatic forceps used as a haemostatic technique?
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
What are the 2 clamping methods of using haemostatic forceps?
- Tip clamping: to occlude small vessels
- Jaw clamping: to occlude larger vessels
How do radiofrequency instruments work as a haemostatic technique?
Use an electric current to coagulate tissue and cause vessel thrombosis
Compare monopolar and bipolar cautery
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
Which is better, monopolar or bipolar cautery and why?
Bipolar
- More precise, requires less current and works better in a wet surgical field than monopolar
Give 2 example of vessel sealing devices
- Electrothermal bipolar vessel sealers
- Harmonic scalpels
What is the best haemostatic technique for large vessels?
Ligatures to occlude the vessel
What two types of ligatures can be used to occlude larger vessels?
- Circumferential
- Transfixing
What are vascular clips used for?
Metal or absorbable polymer vascular clips mounted on single or multiple-use applicators are rapid, convenient but costlier than ligatures.
How do you ensure that vascular clips have permanently occluded a vessel?
- 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
Give examples of causes of wound infection during surgery
- clipping the surgical site
- anaesthesia and surgery time (risk of infection doubles every hour)
- Number of people in the operating room
How can Propofol use increase the chance of a wound infection?
Propofol is suspended in a lipid-based emulsion that can support bacterial growth
How can a patients sex increase the chance of a wound infection?
Male animals are at increased risk of wound infection due to the immunomodulatory effects of androgens
Normal tissue responses to infection can be compromised by which factors?
- Trauma
- Foreign material
- Ischaemia due to shock or trauma
- Poor nutrition
- Chemotherapy
- Systemic disease
What are some examples of endogenous sources of bacterial contamination?
Sources from the patient: skin, respiratory tract, GI tract
What are some examples of exogenous sources of bacterial contamination?
From outside the patient: room air, surgical team, instruments, drapes
How can patient selection and preparation prevent surgical infections?
- 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
How should the surgical team and equipment be prepared to prevent surgical infections?
- 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
What should be used to check equipment has been sterilised?
Biological indicators (glass vials containing heat-resistant bacteria)
