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Pressure Sores

Table of Contents


Tissue ischemia due to prolonged compression, usually against a bony prominence, leading to wounds


Etiology & Pathophysiology

  • Compression of soft tissue, usually against a bony prominence, exceeding capillary pressure leads to decreased perfusion → tissue ischemia → tissue necrosis → ulceration → wound
    • Capillary blood pressure = 12 – 32 mmHg
    • Degree of pressure is inversely proportional to time to ulceration 
      • Greater pressure →  less time required to injure tissue
    • Muscle is more susceptible to ischemia injury than skin
      • Cone shaped volume of injury
Pressure vs. time to ulceration curve
Cone shaped ischemia injury

Risk Factors

  • Must consider extrinsic and intrinsic factors
Extrinsic Intrinsic
 Pressure Spasm
 Friction Autonomic Dysreflexia
 Moisture Infection 
  Increased age
 Sensory loss – paraplegia

Staging Classification

  • Based on the National Pressure Sore Advisory Panel (last updated 2007)
 Stage IStage IIStage IIIStage IV
Depth of Soft Tissue Loss
  • None
  • Skin intact
  • Partial thickness skin
  • Full-thickness skin
  • Subcutaneous fat
  • Down to, but not through, fascia
  • Full-thickness skin loss
  • Subcutaneous fat
  • Muscle
  • Bone
  • Tendon
  • Ligament
  • Joint capsule
Clinical Features
  • Non-blanchable erythema
  • Blister, abrasion or shallow ulcer
  • +/- undermining, tunneling
  • +/- undermining, tunneling
  • Stage III (full thickness wounds) and greater is the cutoff for surgical care
    • Below this, wound care is the treatment



Physical Exam

  • Most common sites affected
    1. Ischial tuberosity (28%)
    2. Trocanter (19%)
    3. Sacrum (17%)
    4. Heel (9%)
    5. Scalp
  • Other sites that can be affected
    • Nose
      • Typically due to nasal cannula or nasotracheal tube
    • Ears 
      • Typically due to nasal cannula tubing or turned head
    • Scapula 
  • When supine, maximal pressure over heels, buttocks, sacrum
  • When sitting, maximal pressure over ischial tuberosities



  • Complete blood count (CBC)
  • Electrolyte panel
  • Hemoglobin A1C
  • Albumin
    • Half-life = 
  • Transferrin
    • Half-life =
  • Pre-albumin
    • Half-life =
    • Inverse relationship with C-reactive protein (CRP)


  • Plain Xray
  • Bone scan
  • MRI


  • Presence of osteomyelitis
    • Bone biopsy = gold standard for diagnosis



  • Eradication of infection
  • Closure of wound


Relieve Pressure

Control Infection

Control Extrinsic factors

Control intrinsic factors





  • 4 inches of foam

Low Air Loss

Air-Fluidized Beds

  • Dolphin
    • Military development to transport dolphins (organs on ventral side of body)
  • Clinatron


Post-Surgical Protocol

  • Do not need to turn patients in Dolphin beds