Anesthesia Considerations 

Prone Position

 

 

Considerations

 

• Effects on respiratory

  • ↑ FRC & PaO2 

  • Chest wall & lung compliance unchanged

• Effects on CVS

  • ↓ stroke volume —> ↓MAP —> reflex tachycardia

  • ↑ pulse pressure (PPV) & stroke volume variation 

    • >14% PPV likely responds to fluid challenge

• Effects of cerebral blow flow (CBF)

  • possible ↓ CBF from partial occlusion of carotid & vertebral arteries, spinal vessels and from compression of venous drainage

• Potential complications

  • Direct pressure injuries:

    • skin necrosis, tracheal, breasts, genitals, pinna

  • Indirect pressure injuries:

    • macroglossia & oropharyngeal swelling, mediastinum, liver/pancreas, vessel occlusion

  • Post-operative visual loss

    • Central retinal artery occlusion —> direct pressure on the eye

    • Ischemic optic neuropathy —> no pressure on the eye

    • Risk factors: ↑ duration, ↑ blood loss, diabetes, HTN, male, atherosclerosis

    • Prevention: avoid direct compression of the globe

  • Peripheral nerve injuries

    • Any peripheral nerve is at risk —> often caused by poor positioning

    • Does not usually present in PACU but 90% appear within 7 days

    • 1/2 patients make full recovery at 1 year 

    • Risk factors: male, ↑ hospital stay, ↑BMI, ↓BMI, diabetes, advanced age

    • Prevention:

      • If possible, place arms at side

      • If arms are abducted they should be < 90° at elbow or shoulder

      • Avoid direct pressure in axilla

      • Pad the elbows

  • Prone accidental extubation

    • If possible: immediately call for bed in the room, roll supine and reintubate

    • Consider LMA for airway rescue

      • Can use fibreoptic scope to intubate through LMA

    • Consider use of fibreoptic scope for reintubation

      • only feasible if scope is near by and face is easily accesible

  • Prone cardiac arrest

    • Chest compressions can be performed:

      • with hands over both scapula or;

      • over the thoracic spine or;

      • open cardiac compressions if doing thoracotomy

    • Defibrillation can be done with pads:

      • antero-posterior

      • R axilla & cardiac apex

      • postero-lateral

    • For high risk patients, consider placing defib pads before turning prone

    • Gloved person to support head/neck to prevent C/S injury during shock

 

Management​

• Six staff members are usually needed to position a patient to prone

• Unstable C/S may need more staff members for log-rolling

• Prior to positioning:

  • disconnect monitoring, infusions and breathing circuit

  • note the supine airway pressures to later r/o bronchospasm/endobronchial intubation

  • ensure endotrachial tube is securely fashioned / tied

  • Bed should not leave the room until correct ETT position / ventilation has been confirmed

 

References

Birte Feix, PhD MB BChir FRCA, Jane Sturgess, MBBS MRCP FRCA, Anaesthesia in the prone position, Continuing Education in Anaesthesia Critical Care & Pain, Volume 14, Issue 6, December 2014, Pages 291–297, https://doi.org/10.1093/bjaceaccp/mku001