Positioning Flashcards
Peripheral Nerve Injury PNI ASA Closed Claims
1990- 2007
Peripheral nerve injuries (PNIs), although rare represent 22% of claims, second only to death.
Mechanisms of injury: stretching, compression, and ischemia
Pt positioning is always suspected
Although the cooperation of the entire surgical team is required, the position for surgery is largely DICTATED and ACCEPTED or MODIFIED by
Surgeon
Primary role for the CRNA/MD
protect the airway and vascular access and to promote physiologic homeostasis while the pt is in the required position.
Most common PNI
Following All Anesthetic Types
1990 to 2010
Spinal cord injury 25%
Brachial Plexus Nerve Damage 19%
Ulnar Nerve Damage 14%
Most common PNI
Following General Anesthesia
1990 to 2010
Spinal Cord 19%
Brachial plexus 27%
Ulnar Nerve 22%
Purpose of Operative Positioning
Surgical Exposure and/or Surgical Access
Comfort
Patient Safety
But positioning may evoke undesirable physiological changes and cause injuries
Most Common Operative Positions
Supine or Dorsal Decubitus Position Trendelenburg Reverse Trendelenburg Lithotomy Prone or Ventral Decubitus Position Lateral Decubitus Sitting
Place person in “natural” position
If possible, allow person to assume the position prior to receiving anesthesia.
Supine Position
Dorsal decubitus
Most common operative position
Position preferred by anesthesia providers access to airway access to arms for IV’s/monitors
hemodynamic reserve is maintained
Arm Boards in Supine
Properly secured to OR table Abducted < 90 degrees, avoids stretch brachial plexus Padded Safety straps Hands- supinated (palm up) NOT pronated
Arms Tucked in Supine
Draw sheet under pt. hip or torso, NOT mattress; elbow padded; palm in
Supine Feet and lumbar Support
-Feet heels not hanging over bed heels padded legs not crossed -Lumbar support slight flexion hips and knees pillow under knees (caution-DVTs) elastic compression stockings and SCD/ sequential compression devices- increase venous return/ decrease risk DVT ***Safety strap***
Supine Position-Complications
Brachial Plexus Injury:
Avoid abduction >90 degrees- produces caudal pressure in the axilla from the head of the humerus
Avoid direct compression at neck Shoulder pads should be avoided
Ulnar: hands and forearms supinated, or
kept in a neutral position w palms toward body, proper padding at elbow
Name other complicatons of Supine Position
Pressure alopecia
Backache
PNIs
Aortacaval syndrome- compression of the abdominal aorta and inferior vena cava by the gravid uterus when a pregnant woman lies on there back.
Lawn chair position
Good for MAC or General. Legs elevated takes pressure off the lower back
Trendelenburg
Tilting a supine pt head down. Reasons: CV and respiratory consequences: venous return FRC pulmonary compliance
Trendelenberg: Cerebral Blood Flow
Increases intracranial vascular congestion-
GRAVITY!!! INCREASED INTRACRANIAL PRESSURE—
which decreases cerebral blood flow
Intraocular pressure increases.
Who would NOT be a good candidate for this position?
Steep Trendelenburg
- -Steep (30-45 degrees) commonly used: robotic/gyn surgeries
- -Once robotic instruments are connected, OR table should not be moved.
Anesthetic Concerns
Cephalad slide How do we prevent? Options: anti-skid pads (gel, egg crate) flexion of knees shoulder braces Strap
Trendelenberg shoulder braces
Use EXTREME caution with shoulder braces! - if they must be used they should be well padded and placed laterally away from the root of the neck over the arcomioclaviular joint
Trendelenburg Anesthetic Concerns
swelling of the face, tongue (macroglossia), and/or larynx
extubation concerns?
stomach above the glottis—airway?
migration of ETT?
Displacement of abdominal contents
Reverse Trendelenburg
“Head up”
often facilitates upper abd sx (shifts abd contents caudad)
Variations of this position may be used for shoulder, neck, intracranial surgery.
This is a variation of the sitting position in terms of physiologic changes.
Reverse Trendelenburg Concerns
caudal slipping
venous return?
Decreases
What happens when the supine (flat) position is resumed? Temporary increase
In the reverse Trendelenburg position, what happens to cerebral perfusion pressure?
Decreases
Lithotomy position
Common: GYN, rectal, and urology
Hips flexed 80—100 degrees
Legs abducted 30-45 degrees from midline
Knees are flexed until lower legs are parallel with torso
Recommendation: legs should be periodically lowered if the sx extends beyond 2-3 hours!
Lithotomy FYI
If herniated disc, positioning might need to be assumed prior to anesthesia.
Pt is usually asked to ”move down” to the foot of the bed.
Intubation difficulties?
Lithotomy Anesthetic Considerations
Raising and lowering legs require a COORDINATED effort.
Lift and position legs simultaneously
Possible nerve injuries in Lithotomy
Improper positioning may lead to the following nerve injuries: femoral, sciatic, obturator, lateral femoral cutaneous, saphenous, common peroneal*.
Lithotomy Position- Candy Can Stirrups
Usually more acute flexion of the knees and/or hips
Watch injury to common peroneal nerve, femoral, sciatic
Lithotomy Position Knee-Crutch Style
Watch popliteal nerve (tibial nerve and common peroneal nerve
Lithotomy Anesthetic Considerations
Requires careful positioning! careful padding of extremities watch fingers and hands major CRUSH injuries Recommended position armboards If arms MUST be tucked, personally visualize fingers/hands prior to raising leg section
Lithotomy Anesthetic Considerations for CV and Respiratory
CV consequences legs elevated inc venous return increases transient increase in CO Respiratory consequences cephalad displacement of abd contents Decrease lung compliance Decrease tidal volume Decrease peak pressures
