pressure sore Flashcards
definition of pressure sore
localised injury to the skin and/or underlying tissue, usually ove rbony prominence, as a result of pressure or pressure and shear
can develop over any part of the body including mucosal surfaces
may be small superficial wounds/blisters involving epidermal elements or larger (sometimes massive) wounds - often covered or filled with necrotic tissue and involving deeper tissues inc fascia, muscle or bone
aetiology of pressure sores
4 factors - pressure, shear, friction, moisture
duration and intensity of pressure are important
irreversible tissue damage can be done from relatively short exposure to high level, or long of low pressure
pressure forces are distrib uted through the soft tissue - extent depending on mechanical properties of soft tissyue and any external devices
shear forces (when slide down bed) may cause stretching and tearing of small bv = ischemia and reperfusion injury - and contribute
friction and moisture can cause superficial injuries inc skin tears and mosisture associated dermatitis - fascilitate transmission of pressure to deeper tissues
inadequate blood flow to skin and soft tissues = tissue ischemia - contributes to sore
unrelieved interfacial pressure that exceeds capillary pressure
RF for pressure sore
increased age
reduced mobility
neurological impairment = loss of sensation/paralysis
surgery
ITU stay
malnourishment
Hx of pressure sores
env factors - Conventional mattresses, operating tables, trolleys, and wheelchair support surfaces do not provide adequate protection
other conditions that prevent normal self-repositioning
pathology of pressure sores
ischemia by capillary occlusion
blockage of lymphatic flow may = accumulation pf toxic waste products
reperfusion injury with accompanying free radicals may damage cells
prologued pressure damage cells = cell death
highest pressure seen in deep tissue, especially along bony prominence - must suseptible = deep injury with little superficial apparent - deep present as dark purple discolouration with intact overlying skin
may evolve over several days to a large necritic ulcer with extensive undermining of wound edges
symptoms of pressure sore
Non-blanching erythema or purple or maroon localised area of discolored intact skin, which may be painful, firm, mushy, boggy, or warmer or cooler than adjacent tissue. - early stage of tissue damage and probably wound formation
shallow open wound or tissue loss on areas subjected to pressure - blister or shiny or dry shallow ulcer involving partial loss of dermis w/o slough indicates grade 2 pressure ulcer
full thickness wound on areas subjected to pressure with or w/o undermining (tunneling) - Full-thickness wound possibly containing some slough with no bone tendon or muscle involvement/exposure = grade 3 pressure ulcer.
full thickness wound with involvement of major tissues on areas subjected to pressure w or w/o undermining (tunneling) - Full-thickness tissue loss with exposed bone, tendon, or muscle possibly containing slough or eschar on some parts of the wound bed indicates a grade 4 pressure ulcer.
when there is exposed bone osteomyelitis should be considered
localised tenderness and warmth around area of wound - suggests infection
increased exudate +/- foul odour
indicators that the pressure sore is infected
development of odour and excess exudate from previously clean wound
change in appearance of wound bed
sudden deterioration in wound or pt
epidemiology of pressure sore
common
rates were considerably higher in people over age 85
investigations for pressure ulcers
clinical dx - tests used to diagnose the complications of pressure sores including infection and osteomyelitis
wound swab when signs of infection - +ve culture in infection (reflect colonisation and not infection - so guidelines dont recommend swab)
ESR - osteomyelitis >100mm/hr
WBC - osteomyelitis >15x10(9)/L
serum glucose - exclude dm
deep tissue biopsy - definitive method for diagnosing an infection - not always practical
MRI - evidence of bony involvement
