Muscle - Meadows Flashcards
Post anesthetic myopathies risk factors
- Prolonged anesthesia times
- hypotension < 70 mmHg MAP
- Hypoxemia
- Lateral recumbency, inadequate padding, poor positioning
- Well muscled/large horses
- Male horses
Post anesthetic myopathy etiology
- inc intracompartmental pressure of muscle from weight of horse ->
- External pressure exceeds perfusion of capillary beds and they collapse ->
- Decreased perfusion leads to
- tissue hypoxia
- myopathy
- neuropathy
* hypoxia and hypotension from anesthesia exacerbate
Post anesthetic myopathy CS
- Hard, swollen, painful muscles
- Lameness, unwillingness/inability to stand
- Increased sweating, incr HR, m. fasciculations
- Myoglobinuria
Post anesthetic myopathy may be difficult to differentiate
myopathy vs neuropathy, may have components of both
Post anesthetic myopathy TX
- Assist to stand
- IV fluid therapy
- NSAIDS +/- corticosteroids
- Analgesics, +/- anxiolytics
- Physiotherapy
- Other
- dantrolene
- methocarbamol
- furosemide
- nasal O2
Post anesthetic myopathy prognosis
Most horses respond w/in 12-24 hours w/appropriate tx
Post anesthetic myopathy Prevention
- Proper padding and positioning on table
- Minimize anesthetic times
- Maintenance BP, PaO2 under anesthesia
Padding dorsal recumbency
Tuber ischii away from edges of bad
Padding lateral recumbency
Pull bottom leg forward
-off-weights dependent triceps and extensor carpi radialis
Positioning for sx avoid
extreme flexion/extension of limbs
Post anesthetic myopathy draft horses
Pre clip, scrub, OR set up ahead of time
Post anesthetic myopathy DDX
Spinal cord necrosis (draft horses)
Malignant hyperthermia
Fibrotic myopathy etiology
- M. trauma resulting in adhesions b/w semitendinosus and adjacent semimembranosus and biceps femoris
Fibrotic myopathy common in
western performance horses
Fibrotic myopathy CS
- Mechanical lameness (not painful)
- Short cranial phase and rapid caudal movement during caudal movement-foot slaps ground
- More obvious at walk than trot
