2. ⢠Surgery
It is often said that it is âcontrolled traumaâ
Carried out in a sterile environment Under
aseptic conditions
3. ⢠Many protocols are put in place to prevent
infections in surgical wounds
o Hand washing
o Gowns and gloves
o Painting and draping
o Drains
o Antibiotics
o Laminar flow theatres
o Sterile instruments
o Sterile dressing
4. ⢠But wound infections can occur despite
these measures causing:
⢠Death
⢠Morbidity
⢠Longer hospital stays
⢠Cosmetically displeasing wounds
9. Anatomy of Skin
⢠Epidermis:
â composed of several thin layers:
stratum basale, stratum spinosum, stratum
granulosum, stratum lucidum, stratum corneum
â the several thin layers of the epidermis contain the
following:
a) melanocytes, which produce melanin, a pigment
that
gives skin its color and protects it from the damaging
effects of ultraviolet radiation.
b) keratinocytes, which produce keratin, a water
Repellent protein that gives the epidermis its tough,
Protective quality.
10. Anatomy of Skin
⢠Dermis:
â composed of a thick layer of skin that contains collagen
and elastic fibers, nerve fibers, blood vessels, sweat
and sebaceous glands, and hair follicles.
⢠Subcutaneous Tissue:
â composed of a fatty layer of skin that contains blood
vessels, nerves, lymph, and loose connective tissue
filled with fat cells
11.
12. Function of Integument
⢠Protection:
â intact skin prevents invasion of the body by bacteria
⢠Thermoregulation:
⢠intact skin facilitates heat loss and cools the
body when necessary through the following
processes:
â production of perspiration which assists in cooling the
body through evaporation
â production of vasodilatation which assists in facilitating
heat loss from the body through radiation and
conduction
â production of vasoconstriction which assists in
preventing heat loss from the body through radiation
and conduction
13. Function of Integument
⢠Fluid and Electrolyte Balance:
â intact skin prevents the escape of water and
electrolytes from the body
⢠Vitamin D Synthesis
⢠Sensation
⢠Psychosocial
14. ⢠The risk of a wound infection depends on
the operation
ďŹFor that reason, operations are classified
into distinct types
o Clean
o Clean-Contaminated
o Contaminated
o Dirty
15. Classification of Wounds
⢠1) Clean Wound:
â Operative incisional wounds that follow nonpenetrating
(blunt) trauma.
⢠2) Clean/Contaminated Wound:
â uninfected wounds in which no inflammation is
encountered but the respiratory, gastrointestinal,
genital, and/or urinary tract have been entered.
⢠3) Contaminated Wound:
â open, traumatic wounds or surgical wounds involving a
major break in sterile technique that show evidence of
inflammation.
⢠4) Infected Wound:
â old, traumatic wounds containing dead tissue and
wounds with evidence of a clinical infection (e.g.,
purulent drainage).
16. Class I :Clean wounds
⢠Elective operations (non emergency)
ďŹNon traumatic injury
ďŹGood surgical technique
ďŹRespiratory, gastrointestinal, biliary and
genitourinary tracts not breached
ďŹRisk of infection < 2%
ďŹEg: mastectomy, hernia repair
17. Class II: Clean - Contaminated
ďŹUrgent or emergency case that is
otherwise clean
ďŹGI, GU or respiratory tracts entered
electively, no spillage or unusual contamination
ďŹMinor break in sterile technique occurre
ďŹEndogenous flora involved
ďŹRisk of infection: <10 %
ďŹEg: appendictomy, bowel resection
18. Class III: Contaminated
⢠ďŹNon-purulent inflammation
ďŹGross spillage from GIT, entry into GU
or
biliary tract in the presence of infected
bile/urine.
ďŹMajor break in technique
ďŹPenetrating trauma < 4hrs old
ďŹChronic open wounds
ďŹRisk of infection: 20%
ďŹEg: GSW, rectal surgery
19. Class IV : Dirty
⢠ďŹPurulent inflammation (abscess)
ďŹPre-operative perforation of GI, GU,
biliary
or respiratory tract
ďŹPenetrating trauma > 4 hrs
ďŹExisting acute bacterial infection or a
perforated viscera is encountered (clean
tissue is transected to gain access to pus).
ďŹRisk of infection: 40%
20. Signs of Infection
⢠ďŹPatient may be systemically unwell
ďŹâ Temp
ďŹTachycardic
ďŹHypotension
ďŹWound breakdown
ďŹWound discharge
ďŹWarm peripheries
ďŹSeptic shock
22. Primary wound healing
⢠ďŹAlso known as âhealing by primary
intentionâ
ďŹThink of a typical surgical wound: the
wound edges are approximated
ďŹMinimal number of cellular constituents
die
ďŹResults in a small line of scar tissue
ďŹMinimizes the need for granulation
tissue
so scarring is minimized
24. Delayed Primary healing
â˘ ďŹ Occurs if wound egdes are not approximated
immediately
ďŹ May be desired in contaminated wounds
ďŹ By day 4: phagocytosis of contaminated
tissues has occurred
ďŹ Usually wound is closed surgically at this
stage
ďŹ If contamination is present still : chronic
inflammation ensues leading to prominent scar
eventually
25.
26. Secondary Healing
ďŹAlso called healing by secondary intention
ďŹA full thickness wound is allowed to heal
by itself: there is no approximation of
wound edges
ďŹLarge amounts of granulation tissue
formed
ďŹWound eventually very contracted
ďŹTakes much longer to heal
27.
28. Normal Wound Healing
ďŹ There are 3 phases
II. Inflammatory phase: Days 0-4
III. Proliferative phase : Days 5-21
IV. Remodelling phase: Days 22-60
29. Wound Healing
ďŹ It can also be classified in 4 stages:
II. Haemostasis
III. Inflammation
IV. Granulation
V. Remodelling
31. Haemostasis
ďŹPlatelets then adhere to damaged
endothelium and discharge ADP
o Which promotes thrombocyte clumping
and âdamsâ the wound
ďŹInflammation is initiated by cytokine
release from platelets
32. Inflammatory Phase
⢠ďŹCapillary dilatation occurs due to:
⢠Histamine
⢠Bradykinin
⢠Prostaglandins
ďŹThis dilatation allows inflammatory cells
to reach the wound site
33. Inflammatory Phase
ďŹThese PMNs or leukocytes have several
functions:
⢠Scavenge for debris
⢠Debride the wound
⢠Help to kill bacteria
35. Granulation Tissue
⢠Newly formed connective tissue, often
found at the edge or base of ulcers and
wounds made up of : capillaries,
fibroblasts, myofibroblasts, and
inflammatory cells embedded in a mucin
rich ground substance during healing
41. Hypertrophic Scars
ďŹRaised, red and thickened
ďŹLimited to boundaries of scar
ďŹOccurs shortly after injury
ďŹCommon on anterior chest and deltoids
ďŹRegresses over time
ďŹRelated to wound tension and prolonged
inflammatory phase of healing
ďŹElectron microscopy: flattened collagen
bundles parallel in orientation
45. Keloid Scars
ďŹ Raised, red and thickened scar
ďŹ Extends beyond original scar boundary
ďŹ Occurs months after injury
ďŹ Does not regress
ďŹ Commoner in darker skinned people
ďŹ Familial tendency
ďŹ ? Autoimmune phenomenon
ďŹ Worsened by surgery and in pregnancy
ďŹ Regresses post menopause
50. Risk Factors for SWI
â Patient-related factors:
â Age > 60, sex (female), weight (obesity)
â Presence of remote infections
â Underlying disease states
â Diabetes, Congestive heart failure (CHF)
â Liver disease, renal failure
â Duration of preoperative stay hospitalization
â > 72 hours, ICU stay
â Immuno-suppression
â ASA (American Society of Anesthesiologists)
â physical status (3,4, or 5)
51. Risk Factors for SWI
Surgery-related factors:
â Type of procedure, site of surgery, emergent
surgery
â Duration of surgery (>60- 120 min)
â Previous surgery
â Timing of antibiotic administration
â Placement of foreign body
â Hip/knee replacement, heart valve insertion, shunt
insertion
â Hypotension, hypoxia, dehydration, hypothermia
52. Surgical factors
ďAtraumatic skin handling
ďEversion of wound edges
ďInversion places keratinised epidermis
between the healing surfaces = delayed
healing
ďTension free closure
ďClean and healthy wound edges
55. Risk Factors for SWI
Surgery related factors:
â Patient preparation
â Shaving the operating site
â Preparation of operating site
â Draping the patient
â Surgeon preparation
â Hand washing
â Skin antiseptics
â Gloving
56. Risk Factors for SWI
Wound-related factors:
â Magnitude of tissue trauma and devitalization
â Blood loss, hematoma
â Wound classification
â Potential bacterial contamination
â Presence of drains, packs, drapes
â Ischemia
â Wound leakage