190624_Positioning Flashcards
PNIs
22% of claims, 2nd only to deaths
Mechanisms of injury: stretching, compression, and ischemia
Pt positioning is always suspected
The position for surgery is largely DICTATED and ACCEPTED or MODIFIED by
the surgion
Primary role for the CRNA/MDA:
protect the airway and vascular access
promote physiologic homeostasis
all while the pt is in the required position.
Ulner neuropathy
in part, unknown
anethesia stress….virus
immunosuppression
Most common PNIs
Spinal cord
Bracial Plexis
Ulner nerve
Purpose of Operative Positioning
Surgical Exposure and/or Surgical Access
Comfort
Patient Safet #1
Bed max weight
only over central column
Most Common Operative Positions
Supine or Dorsal Decubitus Position – Trendelenburg – Reverse Trendelenburg Lithotomy Prone or Ventral Decubitus Position Lateral Decubitus Sitting
Supine Position
Dorsal decubitus
hemodynamic reserve is maintained
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***
Arms Abducted < 90 degrees, avoids stretch brachial plexus
- Hands- supinated (palm up) NOT pronated or
- Draw sheet under pt. hip or torso, NOT mattress; palm in
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 pos w/ palms toward body,
proper padding at elbow
Pressure alopecia Backache PNIs Aortacaval compression syndrome Sit to supine = temp ^BP & CO
Variations of the Supine Position
Lawn chair position:
Good for MAC or General
Legs elevated takes pressure off the lower back
Commonly for pt awake procedures
Trendelenburg
Reasons: HTN, Central Line
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?
- obesity, glocoma, ICP (ex. tumor), cards complications
Steep Trendelenburg
steep (30-45 degrees) we dont like, but we do a lot commonly used: robotic/gyn surgeries Once robotic instruments are connected, OR table should not be moved. Arms tucked!!!
Anesthetic Concerns: cephalad slide ~ PNI How do we prevent? - anti-skid, padding - padding - flexion of knees
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 complications
swelling of the face, tongue (macroglossia), and/or larynx
– extubation concerns?
stomach above the glottis—airway?
migration of ETT?
CV and respiratory consequences: – venous return = increase = work load increase - temp BP increase – Fnctional Residual Capacity = decrease - Vt = decrease – pulmonary compliance = decrease?
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 complications
Anesthetic Concerns
caudal slipping
venous return? decreased
What happens when the supine (flat) position is resumed? Temp increase in BP & Work load
In the reverse Trendelenburg position, what happens to cerebral perfusion pressure? Decreased
Lithotomy position
Common: GYN, rectal, and urology
Hips flexed 80—100 degrees
Legs abducted 30-45 deg from midline
Knees are flexed until lower legs are parallel with torso
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? YES
Raising and lowering legs require a COORDINATED effort = same time same direction
Recommendation: legs should be periodically lowered if the sx extends beyond 2-3 hours!
Risk factors
– low BMI
– smokers
– prolonged duration of sx
Lithotomy complications
Improper positioning may lead to the following nerve injuries: femoral, sciatic, obturator, lateral femoral cutaneous, saphenous, common peroneal*.
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
PNI – common peroneal n. • Compression of the n. between the lateral head of the fibula and the candy-cane bar – sciatic – obturator – lateral femoral cutaneous
Compartment syndrome—think perfusion
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 CV & Resp complications
CV consequences • legs elevated > increase venous return • increases transient inc in CO Respiratory consequences • cephalad displacement of abd contents • decreased lung compliance • decreased tidal volume • increased peak pressures
