07-02: Effects of Immobilization Flashcards
1
Q
Effects of Immobilization on Muscle
A
- Progressive decrease in muscle strength/endurance
- Fatigability
- Decrease in muscle mass and tension
- Body composition changes
2
Q
Strength decline of muscle
A
- 1-3% per day
- 10-20% per week
- Plateaus at 25-40% in 3-5 weeks
- Greater in antigravity muscles (quadriceps, back extensors, plantarflexors)
- Type 1 (slow twitch, oxidative) muscles
- Atrophy quicker in shortened position
3
Q
Fatigability
A
- Decreased ATP and glucose stores
- Decreased ability to use fatty acids
4
Q
Decrease in muscle mass and tension
A
- Decreased fiber diameter (decreased myofibrils and Xsec area)
- Muscle atrophy/wasting 2˚ to decreased muscle synthesis
- 3% per day (decreased fiber size, not number)
5
Q
Body composition changes
A
- Decreased lean body mass (up to 3%)
- Increased body fat (up to 12%)
6
Q
Prevention/Treatment - Muscle
A
- Daily isometric contractions can prevent deterioration
- May take 2-3x longer to “regain” lost muscle mass and strength
- ISO: 20-30% of maximal contraction for several seconds
- ISO: 50% maximal contraction for 1 second
- FES (Functional Electrical Stimulation)
7
Q
Effects of Immobilzation on Soft Tissues
A
- Contracture: Decreased PROM of jt (2˚ to joint, connective tissue, or muscle shortening); one of the “most” function-limiting complications; keep eye on surrounding areas
- Collagen develops cross-links and become less flexible
- Joint: synovial tightening; osteophyte formation; articular cartilage adhesion
- Connective tissue: Loose turns to dense
- Muscle: decreased sarcomeres; muscles (esp. 2-joint), tendons, ligaments may become involved
8
Q
Effects of Immobilzation on Joints
A
- Cartilage degeneration: proteoglycans (ground substance of connective tissue) diminish - resist compressive forces
- Synovial atrophy and fatty infiltrate
- Underlying bone degeneration
9
Q
Contractures - Risk factors
A
- Sustained positioning
- Pain, can lead to muscle guarding to not move painful joint
- Muscle Imbalance
- Pain ex: Local trauma, DJD; Infection, poor circulation; Edema; Amputation (BKA: Knee & Hip, AKA: Hip)
- Muscle Imbalance ex: Paralysis/weakness (esp. 2-joint); Spasticity
- Areas most affected: hips, knees, ankles, hands, elbows, shoulder IR
10
Q
Contractures - Prevention
A
- Bed positioning
- BID range of motion exercises (terminal, sustained)
- Splinting
- Surgery
- Nerve blocks
11
Q
Effects of Immobilization on Ligaments and Tendons
A
- Parallel arrangement of Type 1 collagen is crucial
- Immobility and lack of “stress”: new fibers may be laid down obliquely - causes decreases strength and elasticity
- Water and GAG (glycosaminoglycans) content of the tissues decreases
- Treatment: Periodic longitudinal stress can prevent deterioration
12
Q
Effects of Immobilization on Bone
A
- Osteoporosis: Peaks at 4-6 weeks
- Bone density decreases 40% after 12 weeks; x-ray not sensitive until 35-50% bone loss
- Increased osteoclastic activity
- Decreased rate of bone formation
- WB bones are first to lose mass (first few days)
- Vertebral columns lose up to 50%
- Can lead to fracture, even with minor trauma
- Prevention: WB exercises and muscle contractions
13
Q
Effects of Immobilization on Skin
A
- Pressure Ulcers: Positioning, decreased tissue mass, poor skin care/incontinence, shear
- Pressure Ulcer Sites: Sacrum, heels, ischium, occiput, trochanter
- Edema: May predispose to celluitis
- Subcutaneous bursitis (due to pressure)
- Treatment: Prevention - turning/positioning/seating, inspection (hands-on), skin hygiene
14
Q
Pressure - Supine
A
- Occiput
- Thorax
- Sacrum
- Heels
15
Q
Pressure - Sidelying
A
- Ear
- Shoulder
- Wrist
- Ischium
- Posterior knee
- Heels
