Positioning Flashcards
What are some causes of nerve injury?
- inadequate positioning
- preexisting conditions
- GA
- extremes of body habit us
- procedures >2hrs
What are some mechanisms of nerve injury?
- transaction
- compression
- stretching
- kinking
All = ischemia
Group of nerves running from neck, through shoulder, axilla, and arm
Brachial Plexus
What are the divisions of the the brachial plexus?
- Roots: 5
- Trunks: 3
- Divisions: 3 anterior, 3 posterior
- Cords: 3
- Branches: 5
Randy Travis Drinks Cold Beer
What are the 5 roots of the brachial plexus?
C5, C6, C7, C8, T1
In C-spine, roots come from above vertebrae, after T1, come from below - this is why there is a C8
Name the 5 peripheral branches of the brachial plexus
- musculocutaneous
- axillary
- radial
- median
- ulnar
*only radial, median and ulnar make it to the hand
Where is the lumbar plexus?
Runs along front of leg.
Femoral and saphenous are major branches
Where is the Sacral Plexus?
- Runs along back of the leg
- sciatic nerve is a major branch
Where is the “end-point” of the dermatomes?
The coccyx, not the feet
In the anesthetized pt, describe ventilation and perfusion of lungs: dependent vs non-dependent
- dependent lung has best perfusion
- non-dependent lung has best ventilation
*creates a V/Q mismatch
How does GA create postural hypotension?
-blunts compensatory sympathetic nervous system response with abrupt position changes
Treatment
- temporarily delay further posting changes
- reduce agent
- IVF to increase volume
- pressors
Supine position is also called what?
Dorsal Recumbent
Cardiac and respiratory considerations of supine position
Cardiac
- minimal
- pressures from head to foot approximate mean pressure at level of the heart
Respiratory
- FRC and total lung capacity are reduced bc ABD contents being pushed up
- spontaneous ventilation favors posterior lung (dependent) while controlled ventilation favors anterior (non-dependent) lung
Pressure may change by _____mmHg for each ______cm that a given point varies in vertical height below or above the reference point of the heart
2 mmHg
2.5 cm
CV, Respiratory and Neuro consideration of trendelenburg positoin
Cardiovascular
- activation of baroreceptors
- decrease CO
- decrease in peripheral vascular resistance
- decrease in HR and BP
Respiratory
- diaphragm displaced cephalad and ABD contents decreases FRC
- movement of mediastinum towards head moves carina closer to ETT and can result in tube moving into right mainstem
- increased V/Q mismatch
Neuro
- increased ICP and decrease cerebral blood flow
- increased intraocular pressure in pts with clay come