Skin integrity
What does the skin help the body prevent?
•Water loss (dehydration)
•Entry of pathogens
•Damage from the external environment
What are the 2 types of wounds?
Acute
Chronic
How many stages of pressure injuries are there?
6
What is the medical term for fever?
Pyrexia
What is hyperthermia and hypothermia?
Hyperthermia:
•Overheating without set-point change
•Risk: heat stroke
Hypothermia:
•Core temp <35°C
•Impaired metabolism and organ function
What are the 3 main layers of the skin?
Dermis
Epidermis
Hypodermis
What are the 3 processes of wound healing?
•Filling in the wound (new tissue formation)
•Sealing the wound (epithelialisation)
•Shrinking the wound (contraction)
What are the common sites of pressure injuries?
•Sacrum
•Heels
•Ischial tuberosities
•In neonates and children: occiput (back of the skull) is most common site
What is Pyrexia triggered by?
•Pyrogens (e.g., infection, inflammation)
What controls the thermoregulation of the body?
Hypothalamus
What layers make up the dermis?
Papillary Layer
Reticular layer
What are the phases of wound healing?
Inflammatory phase (0–4 days)
•Vasodilation increases blood flow
•Neutrophils and macrophages clear bacteria and debris
•Classic signs: redness, heat, swelling, pain, loss of function
Reconstructive (proliferative) phase
•Begins approximately 3–4 days after injury
•Lasts up to about 2 weeks
•Involves tissue rebuilding and collagen formation
Maturation (remodelling) phase
•Begins several weeks after injury
•Can continue for months to years (up to a few years)
•Strengthening and remodelling of collagen
•Scar tissue becomes more organised and stronger
What are the clinical features of a deep tissue pressure injury?
Deep red/purple discoloration, persistent non-blanchable area, may form a blister or rapidly evolve to a deep ulcer
When can a fever be classified as harmful?
•Temperature too high (>40°C)
•Prolonged duration
What are the causes of heat production?
•Cellular metabolism (major source)
•Muscle activity (shivering)
Hormones (thyroxine, adrenaline)
What are the functions of the skin?
Protection
Prevent water loss
Thermoregulation
Excretion
Metabolic functions
Barrier to infection
What happens in primary intention healing?
•Occurs in clean, closed wounds (e.g. surgical incisions, paper cuts)
•Minimal tissue loss
•Wound edges are close together
•Heals mainly through collagen production
•Very little epithelialisation and contraction required
•Faster and lower risk of infection
What are the risk factors of developing a pressure injury?
Alteration in mobility or physical activity
•Reduced mobility – fractures, injury, neurological disease, pain
•Unable to independently reposition themselves
Malnutrition and dehydration
•Skin is drier and less able to withstand effects of pressure damage
Moisture
•Wound leakage, incontinence, perspiration
•Skin is less able to resist friction or shearing forces
Alteration in sensation and consciousness
•May not be aware injury has occurred
•Other health conditions – heart disease, diabetes, circulation disorders, history of smoking
What is the mechanism of a fever?
•Hypothalamus ↑ set point (from 37-39 °C) → body perceives “cold”
Results in:
•Shivering
•Vasoconstriction
•Heat production ↑
When fever breaks:
•Sweating + vasodilation
•Heat loss ↑
What are the causes of heat loss?
•Radiation, conduction, convection, evaporation
What does the integumentary system include?
Hair
Nails
Sweat glands
Sebaceous/oil glands
What happens in secondary intention healing?
•Occurs in open wounds with significant tissue loss (e.g. pressure injuries)
•Requires extensive tissue replacement
•Greater epithelialisation, scar formation, and contraction
•Wound edges are not approximated
•Slower healing process
What are the stages of skin damage?
•Pressure reduces blood flow
•Tissue becomes ischemic (oxygen deprived)
•Cell death occurs
•Ulcer forms if pressure continues
•Even short periods of unrelieved pressure can cause damage in high-risk patients.
What can fever increase in an individual's body?
•Metabolic rate
•Oxygen consumption
•Fluid loss
What are the mechanisms of heat gain?
Metabolism:
•Cellular activity produces heat (basal metabolic rate)
Muscle activity:
•Exercise or shivering → rapid heat production
Hormonal regulation:
•Thyroxine & adrenaline ↑ metabolic heat
Vasoconstriction:
•Reduces heat loss → conserves heat
Behavioural responses:
•Adding clothing, seeking warmth