3908843.ppt

Surgical Positioning
Jeffrey Groom PhD, CRNA
Nurse Anesthetist Program
Florida International University

SURGICAL POSITIONING
OBJECTIVES
• Identify the role and responsibility of the
anesthesia provider in patient positioning.
• Describe the complications associated
with improper patient positioning.
• Describe the physiological changes that
occur with the various positions.
• Identify scenarios involving medicolegal
liability associated with improper patient
positioning.

Trendelenberg – Reverse Trendelenberg

Lateral Tilt

Lithotomy

Sitting – Beach Chair

JackKnife - Kneeling

OR Table Attachments

• All positioning schemes have 3 goals:
– 1. Maximum exposure to the surgical area
while maintaining homeostasis and
preventing injury
– 2. Position must provide the Anesthetist with
adequate access to the patient for airway
management, ventilation, medications, and
monitoring
– 3. Promote the enhancement of a
satisfactory surgical result

What happens when the anesthetized patient can’t care for themselves?

When you sleep, you reposition yourself to prevent pressure
ischemia. Under anesthesia, the patient does not reposition
(protect) them self so the responsibility falls to the surgical
team to prevent pressure ischemia & positioning injuries.

• Positioning and Anesthesia
– Blunted or obtunded reflexes prevent
patients from repositioning themselves
for relief of discomfort
– Anesthesia may blunt compensatory
sympathetic nervous system reflexes
that would minimize systemic BP
changes with abrupt position changes
– Rendering patients unconscious and
relaxed may permit placement in position
they may not have normally tolerated in
an awake state
Why is there a risk for injury ?

Patient Injury and
• Most are nerve injuries due to overstretching
and/or compression.
• 90% undergo complete recovery.
• 10% are left with residual weakness or sensory
loss.
• Many injuries can produce lasting disability.
• Many injuries lead to litigation.
• General anesthesia removes many of the bodies
natural protective mechanisms.
• Recognition of risks and prevention is essential.

How do nerves get
injured? Example

•motor fibers (somatic and autonomic) leave the cord via the ventral roots
•sympathetic fibers leave the cord via ventral roots from T1 - L2
•only sensory fibers run in the dorsal root
Peripheral Nerves from Spinal Cord

Preoperative History and
Physical Assessment
Preexisting patient attributes associated
with increased incidence of perioperative
neuropathies:
– extremes of age or body weight,
– preexisting neurologic symptoms,
– diabetes mellitus,
– peripheral vascular disease,
– alcohol dependency,
– smoking,
– and arthritis.

ASA Closed Claims
• 1999 - 670 claims for anesthesia-
related nerve injuries
• #1 - Ulnar nerve (28%)
• #2 - Brachial plexus (20%)
• #3 - Common peroneal (13%)

Ulnar nerve injury
• Caused by arms along side patient in pronation
• Ulnar nerve compressed at elbow between table
and medial epicondyle.
• Prevented by positioning arms in supination.
• Hypotension and hypoperfuison increase risk.

Brachial Plexus Injury
• Excessive arm abduction or external rotation.
• Prevented by avoiding more than 90o abduction.
• Secure arm to prevent arm from falling off of table
or arm board.

Brachial Plexus
• Abduct arms to no more than 90 degrees.
• Minimize simultaneous abduction, external arm rotation,
and opposite lateral head rotation.
• In prone position, maintain abduction and anterior flexion
of arms above head to no more than 90 degrees.
• In lateral position, place chest roll under lateral thorax to
minimize compression of humerus into axilla.

Peroneal nerve
• Caused by direct pressure on the nerve
with the legs in lithotomy position.
• Nerve compressed against neck of fibula.
• Prevented by adequate padding of
lithotomy poles.

Surgical Positions and
Anesthesia Implications

Supine
• Most frequently used position.
• Cervical, thoracic, lumbar vertebrae
should be in a straight, horizontal line.
• Minimal effects on circulation.
• FRC decreases 25-30% from upright.
• Arm boards and arm must be less than
90o abduction angle to the torso.

Supine (con't)
• Arms at greater than 90o angle results in stretch
of the subclavian and axillary vessels resulting
in radial pulse obliteration and arterial
thrombosis.
• Injuries have been reported with as little as 60o
abduction.
• Palms up- relieves pressure on the ulnar nerve
as it passes through the humeral notch at the
elbow.

Supine
• Ulnar nerve injury
–Hypotension and hypoperfusion
increase risk
–Inability to abduct or oppose the
5th finger
–Atrophy of the intrinsic muscles of
the hand (claw hand).

Supine
• Extreme rotation of the head can cause
occlusion and thrombosis of the vertebral
artery.
• Pressure from a mask or head strap can
cause injuries of the supraorbital and
facial nerves.
• Relaxation of the paraspinous muscles
and flattening of the normal lumbar
convexity results in tension on the
interlumbar and lumbosacral ligaments
causing a backache.

Prone
• Induction completed on stretcher, then patient
logrolled to OR table under command of CRNA
• Body ‘logrolled’ as a unit in a smooth, slow, and
gentle manner.
• Neck in alignment with spinal column.
• Eyes and ears protected and not depressed.
• Chest rolls, or bolsters are placed lengthwise on
both sides of the thorax, extending from the
acromioclavicular joints to iliac crest-adequate
lung expansion and diaphragm excursion.

Prone
• Protect female breasts & male genitalia.
• Pillow under legs & ankles to flex knees
and prevent pressure on toes and plantar
flexion of feet.
• Arms at side or extended alongside the
head on arm boards
• Documentation: pressure points padded,
free abdominal and chest expansion,
position of the arms, eye care

Prone
• Cardiac
– Pooling of blood in extremities
- Compression of abdominal muscles
- Decrease preload, c.o., and blood pressure
- Increased SVR and PVR
- Decreased stroke volume and cardiac index
- TEDS or pneumatic sequential compression
stockings to minimize pooling of blood

Prone
• Respiratory
– Decreased lung compliance
– Increased work of breathing
– Thoracic Outlet Syndrome-secondary to
thoracic nerve compression (agonizing,
debilitating, and unremitting pain post-
operatively following overhead arm
placement
– ETT dislodgement - Extubation

Trendelenburg
• Cardiac
– Activation of baroreceptors
– Decrease in C.O., PVR, HR, and BP
– Does not improve C.O. in hypotension & hypovolemia
• Respiratory
– Decreased FRC, total lung capacity and pulmonary
compliance secondary to shift of abdominal viscera
– Increased V/Q mismatching
– Atlectasis
– Increased likelihood of regurgitation
• Use of shoulder braces to prevent cephalad mvmt

Reverse Trendelenburg
• Cardiac
–Decrease in c.o., preload, and arterial
pressure
–Baroreflexes increase sympathetic
tone, HR , PVR.
• Respiratory
–Work of breathing decreased
–Increase in FRC

Lateral Decubitus

Lateral Decubitus
• Usually positioned with bean bag or
position supports.
• Head must be aligned to support the
spinal column and prevent compression
of dependent arm.
• Pillows placed between legs and feet
• Bottom leg flexed to provide stability and
facilitate venous drainage.
• Peroneal nerve susceptible to injury

Lateral Decubitus
• Presents anesthetic challenges-
– Compression of vena cava with kidney rest
– Dependent lung is underventilated-pressure of
abdominal contents and wt of mediastinum.
– Nondependent lung is overventilated because
of increased compliance.
– Blood flows to underventilated lung by gravity.
– V/Q mismatch may manifest as hypoxemia

Lateral Decubitus
• Kidney rest- beneath the bony iliac crest, not
under fleshy waist area
• Axillary rolls- placed at scapula near the axillary
space to relieve pressure on the arm and foster
adequate chest excursion.
• Dependent shoulder, axilla, and deltoid must be
padded.
• Lower arm brought forward to prevent pressure on
brachial plexus.
• Chest surgery- upper arm flexed at elbow and
raised above head to elevate scaplua and widen
intercostal spaces.

Lateral Decubitus
• Cardiac
– Output unchanged unless venous return
obstructed (kidney rest).
– May see decrease in arterial blood pressure as a
result of decreased vascular resistance (R > L).
• Respiratory
– Decreased volume and increased perfusion of
dependant lung, V/Q mismatch potential

Sitting
• Cardiac
– Pooling blood in lower body decreases central
blood volume.
– ABP fall despite increase in HR & SVR. (30%)
– C.O. decreases 20-40%
– Increase in sympathetic /parasympathetic tone
– Intrathoracic blood volume decreases as much
as 500 ml
• Respiratory
– Lung volumes are increased.
– FRC is increased.
– Work of breathing is decreased.

Sitting
• Posterior Foss Craniotomy & shoulder
procedures.
• Full sitting position is uncommon.
• Lounge chair, beach chair.
• Facilitates venous drainage.
• Venous air embolism risk is potential hazard

Sitting
• Complications
– Postural hypotension
– Air emboli
• Potentially lethal
• Chances increase with degree of elevation of op site.
• Dx: change in heart rate, murmur, decreased in exp
CO2, cardiac dysrythmias, change in heart sounds
generated by a parasternal Dopppler.
• TEE most sensitive for detection (0.015 ml/kg/air)
• Gasp breath may be first indicator
• Decreased Pa02, etCO2, increased etN

Sitting
• Complications
– Ocular compression
– Pneumocephalus
– Edema of face, head, and neck due to
prolonged neck flexion resulting in venous
and lymphatic obstruction.
– Sciatic nerve injury
• Bended knees without flexion of the hips
• Foot drop is clinical manifestation

Lithotomy
• Cephalad displacement of the diaphragm.
• Principle hazards:
– Common peroneal- foot drop
– Femoral- decreased or absent knee jerk
– Saphenous-
– Obturator-inability to adduct leg & diminished
sensation over medial side of the thigh
– Sciatic nerve- weakness of all skeletal muscles
below the knee
• Both legs should be elevated & flexed at same
time to avoid stretching of peripheral nerves
• Thighs should be no more than 90o

AANA Scope and Standards
for Nurse Anesthesia Practice
Standard V
Nurse anesthetists should “monitor and
assess patient positioning and protective
measures at frequent intervals.”
Failure to follow professional standards
and guidelines may result in
positioning injuries and liability.

Pommier vs Savoy Memorial Hospital
55 y.o female w/fractured hip
2hr 20 min surgery
Developed peroneal palsy post-op
LIABILITY EXAMPLES
Protective and monitoring measures were not taken nor documented. No
prior injury present. Conclusion at trial – injury would not have occurred
had there not been negligence – res ipsa loquitur.

Shahine vs. Louisiana State University
Medical Center,
680 So. 2d 1352 (La. App., 1996)
• "#6 table with safety strap in place 2" above knees -
supine with bean bag underneath patient post
induction & catheter insertion into the left side, with
right side up, per __M.D. & __M.D, - auxiliary roll in
place (1000cc bag IV fluid wrapped in muslin cover)
- held in place per surgeons until bean bag deflated
with suction - pillow placed under right leg with left
leg bent slightly - U drape in place per surgeons pre
prep - left arm extended on padded arm board -
right arm placed on mayo tray that is padded."
Protective and monitoring measures were taken and documented.
Brachial plexus injury reported postop. No prior injury present.
Conclusion at trial – injury was a risk of the procedure however personnel

ASA Practice Advisory – Sets a legal standard of care
LINK to Advisory in the Course Outline Page

Upper extremity positioning
• Arm abduction should be limited to 90° in supine
patients; patients who are positioned prone may
tolerate arm abduction greater than 90°
• Arms should be positioned to decrease pressure
on the postcondylar groove of the humerus (ulnar
groove).
• When arms are tucked at the side, a neutral
forearm position is recommended. When arms are
abducted on armboards, either supination or a
neutral forearm position is acceptable
• Prolonged pressure on the radial nerve in the
spiral groove of the humerus should be avoided
• Extension of the elbow beyond a comfortable
range may stretch the median nerve

Lower extremity positioning
• Lithotomy positions that stretch the hamstring
muscle group beyond a comfortable range may
stretch the sciatic nerve
• Prolonged pressure on the peroneal nerve at the
fibular head should be avoided
• Neither extension nor flexion of the hip within
normal range of motion increases the risk of
femoral neuropathy

Protective padding
• Padded armboards may decrease the risk of upper
extremity neuropathy
• The use of chest rolls in laterally positioned
patients may decrease the risk of upper extremity
neuropathies
• Padding at the elbow and at the fibular head may
decrease the risk of upper and lower extremity
neuropathies, respectively
Equipment
• Properly functioning automated blood pressure
cuffs on the upper arms do not affect the risk of
upper extremity neuropathies
• Shoulder braces in steep head-down positions may
increase the risk of brachial plexus neuropathies

Postoperative assessment
• A simple postoperative assessment of
extremity nerve function may lead to early
recognition of peripheral neuropathies
Documentation
• Charting specific positioning actions during
the care of patients may result in
improvements of care by (1) helping
practitioners focus attention on relevant
aspects of patient positioning; (2) providing
information that continuous improvement
processes can use to lead to refinements in
patient care; and (3) provide medicolegal
defense

Positioning Checklist

1. Head, neck and cervical spine supported in a
straight line.
2. Scalp, head, and face protected from tight
anesthesia mask/straps.
3. Ears protected from traumatic pressure/objects.
4. Chest and torso kept in physiological position for
adequate full, bilateral respiratory exchange and
expansion.
5. Breasts & genitalia protected from excessive
pressure.

6. Arms in physiological position and supported.
- not to exceed 90 degree extension at
shoulder
- in flexion not hyperextension
- upper arm not hanging over edge of table
or rubbing on metal part of table
- elbow area protected from ulnar pressure
- hands free of pressure and compression
- fingers in slight flexion or neutral extension
- wrist restraints loose or padded
- palms up on armboard
- palms towards body when arms at side

7. Genitals free of trauma, pressure, or rubbing.
8. Back in physiological position, spine in straight line
- slight sacral curvature
- soft small positioning devices under sacral area and
knees to relieve
pressure, pain, or stretching.
9. Thighs/legs in straight line of flexed position; no pressure
to iliac crests, greater trochanters, area bt back & knees,
peroneal nerve on lateral aspects of knees, or to patellas.
10.Heels/ankles/toes free of pressure or rubbing trauma.
11.Safety belt placed snugly over patient w/blanket or towel
between strap and patient’s body to prevent maceration.
12.Other straps or positioning devices placed only over
padded body parts.

During clinical this semester – spend time after
cases learning the operation of the OR table and
proper positioning. Practice on each other to
appreciate “positioning” from patient’s perspective.

3908843.ppt

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