Prone Positioning Under Anesthesia

1
Prone Positioning Under Anesthesia

• Aarti Vadhavkar, M.D.
• CA-2
• February 15, 2008

2
Overview

• Importance of Positioning
• Physiologic Effects
• Support Devices
• Establishing Prone Position
• Complications

3
Positioning Under Anesthesia

• Optimal position offers maximum anatomical
  access yet is physiologically safe for the
  anesthetized patient.
• Peripheral nerve injury 2nd most common
  anesthetic complication represented in the ASA
  Closed Claims Database1.
• First article in literature on effects of body
  position on anesthesia published by Dutton2
  in1933.
• General anesthesia abolishes normal protective
  reflexes ? significant physiologic and functional
  hazards for the prone patient.

1 Cheney FW et al. Nerve Injury Associated with
Anesthesia A Closed Claims Analysis.
Anesthesiology 90 1062-1069, 1999 2 Dutton A.
The Effects of Posture During Anesthesia.
Anesthesia Analgesia 1933 1266-74
4
Physiologic Effects

• Circulatory
• ? intraabdominal intrathoracic pressure?
  ?cardiac output, ?BP
• IVC obstruction ? vertebral venous plexus
  engorgement ? ? bleeding, ? risk of thrombosis
• Head low position venous congestion of face and
  neck ? facial, conjunctival and airway edema
• Head high position risk of venous air embolism

5
Physiologic Effects

• Several studies3,4,5 to assess hemodynamic
  response to prone position
• ?Stroke volume, ? Cardiac index
• ?SVR, ?PVR
• HR, PAOP, Right atrial pressure no change
• Recommend invasive hemodynamic monitors in
  patients with precarious cardiovascular status

3 Backofen JE, Schauble JF. Hemodynamic changes
with prone positioning during general anesthesia.
Anesthesia Analgesia 1995 64 194 4 Wadsworth R.
et al. The effect of four different surgical
prone positions on cardiovascular parameters in
healthy volunteers. Anaesthesia. 1996
Sep51(9)819-22 5 Sudheer PS et al..
Haemodynamic effects of the prone position a
comparison of propofol total intravenous and
inhalation anesthesia. Anaesthesia, 2006
Feb61(2) 138141
6
Physiologic Effects

• Respiratory
• Cephalad shift of diaphragm, compression
  abdominal viscera ? ? FRC, ?work of breathing,
  ?airway pressures
• Ventral supports improved lung volumes,
  oxygenation, and compliance, esp in obese
  patients6
• Ventilation and perfusion are more uniform in
  prone position ? ? V/Q mismatch ? Improved
  oxygenation7

6 Pelosi P. et al Prone positioning improves
pulmonary function in obese patients during
general anesthesia. Anesthesia Analgesia
83578-583, 1996 7 Nyren S. et al. Pulmonary
perfusion is more uniform in the prone than in
the supine position scintigraphy in healthy
humans. Journal of Applied Physiology.
1999861135-41.
7
Support Devices Head Neck

• Surgical pillow/ foam donut, C-shaped face piece,
  horseshoe head rest, Prone Positioner, Prone View
  Helmet.

C-Shaped Face Piece
Prone Positioner

• Mayfield tongs most stable recommended in
  cervical disc disease

Horseshoe Head Rest
8
Support Devices - Ventral

• Rolls of tightly packed sheets, bean bags, convex
  frames (e.g. Wilson frame), pedestal frames (e.g.
  Relton), special OR tables (e.g. Jackson)

• Study8 of 51 spine surgery patients to compare
  different prone positioners.

• Jackson spine table minimal effects on cardiac
  function

8 Dharmavaram S. et al. Effect of prone
positioning systems on hemodynamic and cardiac
function during lumbar spine surgery an
echocardiographic study. Spine. 2006 May
2031(12)1388-93
9
Support Devices

• Limited comparative studies skewed,
  inconclusive
• Choice based on patients physique, available
  equipment, requirements of surgical procedure

10
Establishing Prone Position

• Adequate anesthetic depth and muscle relaxation
• Monitoring leads, IV lines, catheters secure and
  sufficiently long to sustain position change
• Anesthesiologist manages head and airway
• ETT disconnected briefly reconnected after turn
• Acceptable ventilation assured, all monitors
  rechecked and secured

11
Establishing Prone Position

• Head
• Check for migrated monitoring wires, IV lines
  underneath
• Eyes
• Padded, taped shut
• Lubricants controversial
• Ears
• Check for compression, folding of pinna

12
Establishing Prone Position

• Neck
• Assess ROM of C-spine shoulders in pre-op
  visit
• Rule out cervical spine arthritis, thoracic
  outlet syndrome, cerebrovascular disease .

13
Establishing Prone Position

• Arms
• Padded armboards
• Arms abducted, flexed at elbows
• lt90 arm abduction
• relieves tension on shoulder muscles
• ?compression of axillary neurovascular bundle by
  humeral head

• Protective padding Ulnar nerve at cubital
  tunnel, radial nerve in spiral groove of humerus
• Check for full pulses at wrists

14
Establishing Prone Position

• Torso
• Ventral longitudinal supports to relieve chest
  and abdominal wall compression
• Breasts
• Positioned medially and checked for compression
• Genitalia
• Pillow placed over caudal end of longitudinal
  supports
• Knees, Toes
• Flexed and padded, esp in prone kneeling position
• Pillow to support ankles off table surface

15
Establishing Prone Position
9 Martin JT and Warner MA (eds). Positioning in
Anesthesia and Surgery (3rd edition) . WB
Saunders, PA 1997.
16
Complications
Risk Factors

• Peripheral neuropathies
• Nerve entrapment syndromes e.g. carpal tunnel
  
• Diabetes mellitus
• Osteoarthritis, Rheumatoid arthritis
• Pre-existing decubiti
• Venous stasis
• Previous traumatic injury, fractures

• Advanced age
• Alcohol abuse
• Malnutrition
• Vitamin deficiencies
• Corticosteroid use
• Contractures
• Morbid obesity
• Hypothyroidism
• Renal disease

17
Complications

• Airway
• Accidental extubation
• Obstruction of ETT bloody secretions/ sputum
  plugs
• Facial, Airway edema
• Prolonged head low position, ? crystalloid
  infusion
• Problems with extubation

18
Complications

• Accentuation of pre-existing trauma
• Multiple skeletal injuries may be further
  exacerbated during positioning
• Neck injury
• Excessive lateral torsion or hyperflexion ?
  Post-op pain, cervical nerve root or vascular
  compression

19
Case Report

• 40/M w/h/o C-spine whiplash injury s/p C4-5-6
  discectomy underwent excision of soft tissue mass
  in prone position ?GA 10
• C-spine stabilization, awake fiber optic
  intubation, horseshoe head rest
• PACU c/o dizziness, headache, painful numbness
  of right face, slurred speech and myoclonic
  spasms of left side extremities
• MRA Rt vertebral artery stenosis ? lateral
  medullary syndrome
• Causes excessive rotation or extension of head
  during positioning, hypoperfusion under GA ?
  exacerbated vertebral arterial insufficiency.

10 Chu YC et al. Lateral Medullary Syndrome after
Prone Position for General Surgery. Anesthesia
Analgesia. 2002 Nov95(5)1451-3
20
Injuries Skin Soft Tissue

• Key factors amount and duration of pressure
• High risk areas face, breasts, genitalia bony
  prominences e.g. malar regions, chin, iliac
  crests, knees, toes
• Uncontrollable factors e.g. duration of surgery
  may override protective measures ? pressure injury

21
Case Report

• 44/M ASAI underwent revision of right lower
  extremity scar in prone position ?GA11 . H/o
  multiple LE surgeries in prone position. No known
  allergies.
• PronePositioner used, uneventful operative course
• POD1 Red rash over face , took Benadryl.
• POD2 To ER with c/o facial, lip and orbital
  swelling and itching. Treated with prednisone and
  Benadryl
• Allergy/Immunology Consult Allergic contact
  dermatitis from sensitization to urethane foam in
  PronePositioner during his previous surgeries.

11 Jericho BG and Skaria GP. Contact Dermatitis
After the Use of the PronePositioner Anesthesia
Analgesia 2003,97(6)1706-8
22
Injuries Eye

• Corneal abrasions
• Orbital edema
• Postoperative visual loss ( POVL)
• Rare unclear etiology
• ASA Closed Claims Project 12 management of
  anesthesiologists frequently implicated
• ASA Professional Liability Committee created the
  POVL Registry 13 in 1999

12 ASA Closed Claims Project http//www.asaclosedc
laims.org/ 13 American Society of
Anesthesiologists Task Force on Perioperative
Blindness Practice advisory for perioperative
visual loss associated with spine surgery a
report by the American Society
23
POVL Registry

• Goal Identify risk factors associated with POVL
• Retrospective analysis of patients who reported
  visual loss lt 7 days postop

CRAO 11
Unknown 9
CARDIAC 9
VASCULAR 5
SPINE 72
PION 60
AION 20
ORTHO. 4
MISC. 10
Distribution of cases from the ASA POVL Registry
Distribution of 93 ophthalmic lesions associated
with POVL after spine surgery
24
POVL
25
Injuries Nerves

• Mechanisms
• ? stretch, compression ? ischemia
• Occur despite adequate protection1,12 ? other
  factors?
• Prone patient
• Supraorbital, facial, mandibular nerves
• Brachial plexus and its peripheral components

1 Cheney FW et al. Nerve Injury Associated with
Anesthesia A Closed Claims Analysis.
Anesthesiology 1999. 90 1062-1069. 12 ASA Closed
Claims Project http//www.asaclosedclaims.org/
26
Injuries Brachial Plexus
9 Martin JT and Warner MA (eds). Positioning in
Anesthesia and Surgery (3rd edition) . WB
Saunders, PA 1997.
27
Complications

• Other
• Compartment syndrome, Rhabdomyolysis
• Venous air embolism
• Visceral ischemia pancreatitis
• Undiagnosed space occupying lesions

28
Case Report
How does one manage cardiac arrest in a prone
patient?

• 60/F underwent decompression laminectomy T11-L1
  for invasive tumor ?GA in prone position14
• Prolonged surgery, ? blood loss
• 9 hrs ?BP ? pulseless V tachycardia VAE ?
• Field flooded with NS, ventilated with 100 O2
• Open surgical wound, bleeding, protruding
  surgical metalwork
• Defibrillator paddles placed in right axilla and
  left apex ? 200J DC shock ? Sinus rhythm

14 Brown J. et al. Cardiac arrest during surgery
and ventilation in the prone position a case
report and systematic review. Resuscitation 2001.
50(2) 233-238
29
Core Competencies

• Patient Care provided medical care to patient
  discussed
• Medical Knowledge reviewed current literature
  regarding physiologic effects, support devices,
  complications and management of prone positioning
  under anesthesia
• Practice-based learning and improvement
  assimilated scientific evidence pertinent to this
  case provided reflective practice for future
  improvement in patient care
• Interpersonal and Communication skills discussed
  the complication with the patient and
  neurosurgical team
• Professionalism showed respect and
  accountability to the patient and provided
  follow-up care to the patient
• Systems-based practice coordinated care between
  Neurosurgical, Anesthesia and Dermatology
  services.

30
Reflective Practice

• In addition to risks inherent with general
  anesthesia, it might have been prudent to discuss
  complications associated with positioning in
  informed consent
• Earlier detection could have resulted in faster
  healing of lesions.

31
References

• Cheney FW, Domino KB, Caplan RA, Posner KL Nerve
  Injury Associated with Anesthesia A Closed
  Claims Analysis. Anesthesiology 1999. 90
  1062-1069.
• Dutton Adena The Effects of Posture During
  Anesthesia. Anesthesia Analgesia 1933. 1266-74
• Backofen JE, Schauble JF. Hemodynamic changes
  with prone positioning during general anesthesia.
  Anesthesia Analgesia 1995. 64 194
• Wadsworth R. et al. The effect of four different
  surgical prone positions on cardiovascular
  parameters in healthy volunteers. Anesthesia
  1996. Sep51(9)819-22
• Sudheer PS et al.. Haemodynamic effects of the
  prone position a comparison of propofol total
  intravenous and inhalation anesthesia. Anesthesia
  2006. Feb61(2) 138141
• Pelosi P. et al The prone position during
  general anesthesia minimally affects respiratory
  mechanics while improving FRC and increasing
  oxygen tension. Anesthesia Analgesia 1995.
  80955,
• Nyren S. et al. Pulmonary perfusion is more
  uniform in the prone than in the supine
  position scintigraphy in healthy humans. Journal
  of Applied Physiology. 1999861135-41.
• Dharmavaram S. et al. Effect of prone
  positioning systems on hemodynamic and cardiac
  function during lumbar spine surgery an
  echocardiographic study. Spine 2006. May
  2031(12)1388-93
• Martin JT and Warner MA (eds). Positioning in
  Anesthesia and Surgery (3rd edition) . WB
  Saunders, PA 1997.
• Chu YC et al. Lateral Medullary Syndrome after
  Prone Position for General Surgery. Anesthesia
  Analgesia 2002 .Nov95(5)1451-3
• Jericho BG and Skaria GP. Contact Dermatitis
  After the Use of the PronePositioner. Anesthesia
  Analgesia 2003,97(6)1706-8.

32
References

• ASA Closed Claims Project http//www.asaclosedclai
  ms.org/
• American Society of Anesthesiologists Task Force
  on Perioperative Blindness Practice advisory for
  perioperative visual loss associated with spine
  surgery a report by the American Society of
  Anesthesiologists Task Force on Perioperative
  Blindness Anesthesiology 2006. 10413191328.
• Brown J. et al. Cardiac arrest during surgery
  and ventilation in the prone position a case
  report and systematic review. Resuscitation 2001.
  50(2) 233-238 Atwater BI et al. Pressure on
  the face while in the prone position Prone View
  versus Prone Positioner. Journal of Clinical
  Anesthesia 2004. Mar16(2)111-6.
• Baig MN et al. Vision loss after spine surgery
  review of the literature and recommendations.
  Neurosurgery Focus 2007. 23(5)E1.
• Chen SH et al. Paraplegia by acute cervical disc
  protrusion after lumbar spine surgery. Chang Gung
  Medical Journal 2005..Apr28(4)254-7.
• Palmon SC, et al. The effect of the prone
  position on pulmonary mechanics is
  frame-dependent. Anesthesia Analgesia 1998.
  Nov87(5)1175-80.
• Rehder K. et al. Regional intrapulmonary gas
  distribution in awake and anesthetized-paralyzed
  prone man. Journal of Applied Physiology 1978.
  45528.
• Kaneko K. et al. Regional distribution of
  ventilation and perfusion as a function of body
  position. Journal of Applied Physiology 1966.
  21767777.
• Manna EM et al. The effect of prone position on
  respiratory mechanics during spinal surgery.
  Middle East Journal of Anesthesiology 2005.
  Oct18(3)623-30