Editing Pressure injuries


''For operative pressure injuries, see separate topic under 'Operating theatre'''


Lesions caused by unrelieved pressure that results in damage to the underlying tissue

== Risk factors ==

* '''Immobility'''
* Older age
* Obesity
* Malnutrition
* Ischaemia
* Sensory loss
* Medical comorbidities and frailty
* General anaesthetics
* Poor skin
* Presence of implants (joint replacements etc.)

== Pathophysiology ==

* Generally the result of soft tissue compression between a bony prominence and an external surface for a prolonged period
* Complex pathogenesis, with consideration to interaction between injury characteristics and local tissue characteristics, rather than just pressure. The deformity produced locally by pressure is likely important.
** Pressure
** Friction (less important)
** Shearing forces - such as when patients are on an incline
** Moisture (less important)
* Pressure to the skin in excess of arteriolar pressure (32mmHg) may lead to local hypoxia and accumulation of metabolic waste products
* Muscle is the most susceptible to injury, followed by fat, and then skin - so deep injury can occur without much visible change. High-grade injuries can start with deep injury that subsequently becomes evident on the skin. It is less likely that there is a uniform progression from grade 1 to grade 4.

== Prediction ==

* Norton or Braden scales can be used to predict
* Specificity and sensitivity 60-80% and low interobserver reliability

== Staging: ==

* NPIAP system - describe the INITIAL appearance of the area. Not useful to guide treatment progress, just what it looks like initially.

'''Staging of pressure-induced skin and soft tissue injuries[1]'''
{| class="wikitable"
|'''Stage'''
|'''Description'''
|-
|1
|Skin intact but with non-blanchable redness for >1 hour after relief of pressure.
|-
|2
|Blister or other break in the dermis with partial thickness loss of dermis, with or without infection.
|-
|3
|Full-thickness tissue loss. Subcutaneous fat may be visible; destruction extends into muscle with or without infection. Undermining and tunneling may be present.
|-
|4
|Full-thickness skin loss with involvement of bone, tendon, or joint, with or without infection. Often includes undermining and tunneling.
|-
|Unstageable
|Full-thickness tissue loss in which the base of the ulcer is covered by slough and/or eschar in the wound bed.
|-
|Deep tissue pressure injury
|Purple or maroon localized area of discolored intact skin or blood-filled blister due to damage of underlying tissue from pressure and/or shear.
|}


== Management ==

=== General: ===

** Pain control
*** Topical anaesthetics have limited evidence - probably don't use
*** Topical opioids have shown some small benefit in trials
*** Mostly will require systemic analgaesia
*** Reconsider wound management techniques if pain is bad
** Treat infection only in clinically infected wounds. Evaluate for osteomyelitis.
** Assess and improve nutrition
** Reposition every two hours. Use support surfaces to offload pressure from the area. Consider air-fluidised beds for patients that are difficult to position due to multiple pressure areas.
** Prevent contamination
*** Little evidence for IDC/rectal tube
*** Consider colostomy if site is prone to faecal contamination
** Daily monitoring with wound care nurse.

=== Wound care: ===

** General principles:
*** Debride necrotic tissue
*** Appropriate dressings or wound packing to promote healing
*** Wound coverage
** Specific regimens:
*** Stage 1: cover for protection
*** Stage 2: generally need little debridement. Require a dressing to maintain a moist wound environment.
*** Stage 3 and 4: require debridement of necrotic tissue and possibly treatment of infection. Following wound bed preparation, coverage may involve skin grafting or other tissue transfer procedures.
**** If the wound is small and relatively clean, can try to manage on the ward with debriding dressings such as Prontosan

=== Surgical ===

** Debridement
*** Debride all necrotic tissue, preferably in OT in most cases
*** Obtain tissue culture
*** Bone biopsy, if involved, for confirmation of OM
*** Meticulous haemostasis is necessary, because these wounds have a propensity to bleed
*** Use outside-to-inside approach, starting from skin
*** Usually apply a VAC - quite good evidence for it in this setting
** Diversion
*** Consider for patients with longstanding and deep sacral and ischial pressure injuries
*** Can end up being permanent
*** In selected patients, can improve healing times
** Reconstruction
*** Need a stable wound bed, free of infection, with optimised medical factors before considering
*** Padding of pressure points with full thickness, well-vascularised skin
*** Fasciocutaneous flaps are often used for closure



== Prognosis: ==

* One study looked at >1000 nursing home patients to assess the proportion that were ulcer-free at six months:
** Stage 2 - 70%
** Stage 3 - 50%
** Stage 4 - 30%
*** 77% of stage 4 ulcers followed for two years eventually healed

[[Category:Skin, soft tissue and wounds]]