Positioning

Repositioning Checklist

Function and position must be checked after moving:

  • Airway
    • Patent
    • In correct position
  • Breathing
    • Capnography present
    • Pulmonary compliance appropriate
    • Bilateral air entry
    • SpO2 waveform present
  • Circulation
    • Monitoring stable
    • IV lines connected and accessible
  • Disability
    • Eyes
      Free of pressure.
  • Exposure
    • Bony areas padded

Positions

Include:

  • Supine
  • Trendelenburg
  • Reverse Trendelenburg
  • Lateral
  • Prone

Supine

  • ↑ risk of airway obstruction
  • ↓ FRC
  • ↓ VT
  • ↑ VR and CO
  • Loss of lumbar lordosis
    May lead to postoperative lower back pain.
  • Use a wedge or table tilt to prevent aortocaval compression in the pregnant patient

Trendelenburg

The head-down position:

  • Airway oedema
    Due to ↑ venous pressure.
    • Check cuff leak prior to extubation
    • Consider dexamethasone
  • Passive regurgitation of gastric contents
  • Further reduction in FRC, compliance, and ↑ atelectasis
    Greater in obese patients due to weight of abdominal viscera.
  • Results in more extreme CVS changes than the supine position
    • ↑ VR and LVEDP
      Beware cardiac failure.
  • Raised ICP
  • Raised IOP

Reverse Trendelenburg

The head-up position:

  • Reduced VR
    May lead to hypotension.
  • Reduces ICP
    Via ↑ venous drainage.
  • Reduces CCP
    Via ↓ in MAP at the level of the Circle of Willis.
  • ↑ risk of venous air embolism

Lithotomy

  • ETT displacement
    ETT typically moves cephalad in this position.
  • ↑ VR
    Venous pool drains from lower limbs.
    • May lead to volume overload
  • ↑ DVT risk
  • ↑ compartment syndrome risk
    Especially with prolonged (>5 hour) procedures. Due to calf compression
  • Neuropathy risk
    • Sciatic and obturator
      Extreme flexion of the hip joints ↑ this risk.
    • Peroneal and saphenous nerve
      Via calf compression.

Lateral Position

In the positively-pressure ventilated patient in the lateral position:

  • ↑ V/Q mismatch
    May lead to hypoxia. Occurs as the:
    • Dependent lung is relatively underventilated and overperfused
    • Non-dependent lung is relatively overventilated and underperfused
  • Highest risk of ocular complications
    Predominantly corneal abrasions.
  • Brachial plexus compression
  • Axillary compression
    Mitigate with use of an axillary roll.
  • Venous outflow obstruction of dependent arm
  • Peroneal and saphenous nerve compression
    Avoid by placing padding between legs.

Seated/Beachchair

  • Airway oedema
  • ↓ cerebral perfusion pressure
    Consider arterial line placed at the level of the EAM to maintain cerebral perfusion.
    • Catastrophic cerebral hypoperfusion is rare but described
  • Reduced venous return
    Can lead to significant hypotension.
  • Venous air embolism
    Subatmospheric venous pressure and non-collapsible dural sinus predispose to this.

Prone

Covered in detail under prone positioning.

References

  1. Knight DJW, Mahajan RP. Patient positioning in anaesthesia. Continuing Education in Anaesthesia Critical Care & Pain. Oct 2004.
  2. Pearce H, Soeding P, Hoy G. Surgery in the “beach chair” position. ANZCA Bulletin. December 2013.