Lecture 4 - Biosurgical products Flashcards
What are the principle of chronic wound treatment?
- Removal of necrotic tissue (Surgical, mechanical, enzymatic, chemical)
- Prevent wound infection (dressings and antiseptics)
- Encourage healing (Modern dressing; hydrocolloid, hydrogel and alginate)
What are the advantages of maggot debridement therapy?
Maggots clean wound by dissolving necrotic and infected tissue. They disinfect wound by killing bacteria even where antibiotic doesnot work. They prevent further infection and this promote healing.
Give examples of the maggot secretions.
Maggots secrete factors that breakdown dead cells such as serine proteases and aminopeptidase. They also secrete urea and allantoin which softens and moisten the skin. They secrete antibacterial substances such as seraticin and some other anti inflammatory factors.
How can maggots be applied to wounds?
There are two ways of applying maggots to wounds. The free range larvae which is applied directly to the wound and contained larvae dressings where the maggots are packaged in foam dressings.
How are the free range larvae applied to wound?
A barrier is applied to the surrounding skin for protection and then the maggots are applied to the wound. The number of maggots depends on the depth and surface area of the wound. After that the wound is covered with a moist swab and a perforated film dressing. It is left for 3-4 days then it is removed and disposed in clinical waste.
What types of wounds can maggot not be used in?
Dry wounds
Body cavity wounds
What are the factors influencing outcome of maggot therapy?
Age if over 60
Type of wound specially deeper wounds
Less effective in chronic limb ischaemia
What are the benefits of using leeches in microsurgery?
- Drain blood from congested sites
- Relieve building pressure
- Prevent blood clotting in small veins in graft
Give the names and functions of the substance found in leech saliva.
Hirudin - inhibits coagulation by binding to thrombin
Calin - inhibit coagulation by inhibiting collagen mediated platelet aggregation
Destabilise- dissolves fibrin
Hirustasin - inhibit serine proteases
Bdellins - Anti inflammatory action
Hyaluronidase - antibiotic
Factor Xa inhibitor - anticoagulant
Carboxypeptidase A inhibitors - increase blood flow at bite site
Acetylcholine - vasodilator
How to care for leeches?
Temperature should be maintained between 4 to 15 C and should not be placed in direct sunlight.
Should use distilled water with hirudosalt for consistency.
The container should have a lid with small perforations to prevent escape.
Give a step by step of how to apply leeches.
Clean the patient’s skin with soap and water then clean thoroughly with distilled water.
Place a dampened cloth with a hole in the middle for the area to be treated (to prevent the leech from wandering off)
Choose a hungry active small leech and point its head toward the hole.
Attachment occurs quick, if not prick skin to produce tiny droplet of blood.
Once attached, it has to be left for 30-60 minutes and check if leech detaches, this means blood flow is poor.
Once fed, leech will detach and should be placed in a container labeled used and dispose.
How to dispose of used leeches?
The leeches are sedated in 8% alcohol then killed in 70% alcohol. Then they are discarded via a sluice or incinerator.
Used leeches should not be used on a second patient or be returned to a pharmacy.
Give the post wound care tips.
The bite should be encourage to bleed by gentle removal of blood clot at regular intervals.
Prevent infection by routine observation( swab if needed)
If bleeding is prolonged, Haemoglobin levels should be checked daily.
Give the considerations and contraindication so using leeches.
Should consider infection as a complication and allergy
Contraindication can be due to arterial insuffiency as this could cause infection.
