Surgical Positioning

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Surgical Positioning
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Jeffrey Groom, PhD, CRNAAssociate Professor,
Anesthesiology NursingFlorida International
University
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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.

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Surgical Positioning
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• 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

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Surgical Positioning

• Positioning and Anesthesia
• Blunted or obtunded reflexes prevent patients
  from repositioning themselves for comfort
• 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

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Surgical Positioning ASA Closed Claims

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

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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.

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Surgical Positioning

• 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.

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Surgical Positioning

• Brachial Plexus Injury
• Excessive arm abduction or external rotation.
• Prevented by avoiding more than 90o abduction.
• Should avoid arm falling off of table.

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Surgical Positioning

• 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.

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Brachial Plexus
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Surgical Positioning

• 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.

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Surgical Positioning
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Nerve Injury and Surgical Positioning

• 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.

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Surgical PositioningSupine

• 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.

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Surgical PositioningSupine (con't)

• 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.

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Surgical PositioningSupine

• 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).

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Surgical PositioningSupine

• 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.

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Surgical PositioningProne
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Surgical PositioningProne

• 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 of the thorax, extending from the
  acromioclavicular joints to iliac crest-?adequate
  lung expansion and diaphragm excursion.

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Surgical PositioningProne

• 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

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Surgical PositioningProne

• 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

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Surgical PositioningProne

• 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

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Surgical PositioningTrendelenburg

• 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

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Surgical PositioningReverse Trendelenburg

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

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Surgical PositioningLateral Decubitus
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Surgical PositioningLateral 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

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Surgical PositioningLateral 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

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Surgical PositioningLateral 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.

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Surgical PositioningLateral 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 gt L).
• Respiratory
• Decreased volume and increased perfusion of
  dependant lung, V/Q mismatch potential

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Surgical PositioningSitting

• 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.

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Surgical PositioningSitting

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

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Surgical PositioningSitting

• 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

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Surgical PositioningSitting

• 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

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Surgical PositioningLithotomy

• 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

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Scope and Standards for Nurse Anesthesia
PracticeStandard V

• Nurse anesthetists should monitor and assess
  patient positioning and protective measures at
  frequent intervals.

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Pommier v Savoy Memorial Hospital

• 55 y.o female w/fractured hip
• 2hr 20 min surgery
• Developed peroneal palsy
• Res ipsa loquitur

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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."

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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

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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

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• 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

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• 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

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

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• 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

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• Positioning Checklist
• Genitals free of trauma, pressure, or rubbing.
• 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.
• 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.
• Heels/ankles/toes free of pressure or rubbing
  trauma.
• Safety belt placed snugly over patient w/blanket
  or towel between strap and patients body to
  prevent maceration.
• Other straps or positioning devices placed only
  over padded body parts.