Positioning Flashcards
What is the anesthetist’s responisibility regarding positioning?
What are the goals of positioning?
- The anesthetist is responsible for supervising and assuring no nerve or soft tissue injury and to minimize physiological changes and treat changes appropriately
- Goals:
- appropriate surgical exposure/access
- comfort
- patient safety
How/why must the anesthetist be extremely vigilant?
- B/c the patient is unconscious, has no sensation, and is muscle relaxed
- You should establish new positions gradually, especially after a long surgery
- Documentation:
- describe baseline BOM
- describe intra-op position
- use of padding
- frame
- body position
- checks done and frequency
What is the weight limit of the OR table?
How is the pt transfered to the OR table?
- 136 kg (300 lbs)
- Transfer:
- OR table and stretcher must be locked
- make sure OR table has a draw sheet
- staff members on both sides
- pt moves self or moved by staff
- make sure head and neck are aligned with spine
- watch exctremeties
- watch IVs and monitors
- then apply safety strap
What are the most common operative positions?
- supine or Dorsal Decubitus position
- trendelenberg
- reverse trendelenberg
- Lithotomy
- Prone or ventral decubitus position
- lateral decubitus
- sitting
What are the benefits of the supine position?
- great access to airway
- access to arms for IVs and monitors
- less physiologic changes than in other positions
- ** most common, and most preferred by anesthesia
How do you appropriately position the head in supine position?
why?
- Pillow under the head
- allows proper sniffing position
- avoids dorsal extension and lateral flexion of neck
- avoids brachial plexus stretch and vascular compromise in neck
- doughnut shape pillow prevents allopecia
- no pressure on the eyes??
How can you arrange the arms in supine position?
- Arm boards:
- properly secured to table
- abducted <90 degrees to avoid stretch of brachial plexus
- padded
- safety straps
- hands supinated NOT pronated
- tucked
- draw sheet unter pt’s hip or torso, NOT mattress
- elbow padded, palm facing in
How should you position the feet in supine position?
How can you provide lumbar support?
- Feet
- heels not hanging over bed
- heels padded
- legs not crossed
- compression socks or SCT to reduce DVT risk
- Lumbar support
- slight flexion hips and knees
- pillow under knees (with caution, could add to DVT risk)
- legs/feet not crossed
What are different ways (mechanisms) that positioning can cause peripheral nerve injury?
- stretching- most common, can progress to ischemia
- compression
- kinking
- ischemia
- transection
Why is the brachial plexus at risk of injury?
What can cause a brachial plexus positioning injury?
- Because the nerve travels a long superficial course through fixed points
- the vertebral foramina fascia
- the clavicle
- the scapula
- the humerus
- positioning injury can occur with:
- neck extension, head turned to side or sagging
- excessive abduction of arm >90 degrees
- if arm or arm board falls off table
- depressed/sagging shoulders in sitting position
- extending arms overhead when prone
- compression of plexus agains thorax when lateral
- shoulder braces
- sternal retractors in cardiac surgery
What would be expected deficits from a brachial plexus injury?
- limp or paralyzed arm
- lack of muscle control in arm, hand, wrist
- lask of sensation in arm or hand
What can cause injury to the radial nerve?
What deficits occur if it is injured?
- Injury is due to external compression of the radial nerve on the lateral aspect of the humerus against:
- surgical retractors
- ether screet
- mismatched arm board
- repeat BP inflation
- Deficit if injured:
- loss of extension of forearm
- weakness of supination
- loss of extension of hand (wrist drop)
- loss of sensation in lateral arm, posterior forearm, part of hand
What is the most common postoperative peripheral nerve injury?
What can cause this?
- Ulnar nerve injury- higher incidence in muscular men; cannot always be prevented
- The nerve runs in the groove between the olecranon of ulna and medial epicondyle of humerus
- Injury with:
- compression of nerve between the olecranon of ulna and medial epicondyle of humerus (entrapment with arm extension)
- stretch with severe elbow flexion
- dislocation over medial epicondyle with pronation of hand causing stretching
- compression against bed
- misplaced BP cuff
What kind of deficits would an ulnar nerve injury cause?
- inability to abduct or oppose 5th finger
- loss of grip strength, esp. ulnar side of fist
- loss of sensation of palmar surface of hand and 4th and 5th fingers
- eventually, leads to atrophy of intrinsic muscle of hand (claw hand)
What are the cardiovascular changes seen in a pt in the supine position?
- minimal effects on circulation and perfusion
-
initially, will have increased venous return
- increased preload, SV, CO. BP
- this activates baroreceptors which decrease sympathetic outflow and incrases PSN impulses, leading to decrease in HR and PVR (unless blunted by anesthetics!)
-
later, they have reduced venous return due to venous pooling in lower extremities
- decrease CO, BP
- increase HR
- *possible IVC compression by masses, pregnancy, obese abdomen, or ascites may decrease venous return and CO even more