FRCA Notes

Pinned Cardiac Arrest

Resources

  • Cardiac arrest under anaesthesia for non-cardiac surgery is uncommon
  • The overall incidence is 0.01 - 0.34%, although the precise incidence in neurosurgical patients is unknown

Bradycardia → asystole

  • Risks include:
    • Operations where there is dural manipulation e.g. tentorium
    • Use of cold irrigation fluids
    • Trigemino-cardiac reflex

  • May be pertinent to give prophylactic anti-cholinergic if high risk of severe bradycardia or asystole
  • Most bradyarrhythmias respond to cessation of surgical cause
  • If the initial rhythm of cardiac arrest is asystole, ensure all potential surgical causes are eliminated

  • Management of bradycardia is as per standard ALS:
    • Atropine 500 - 600μg IV
    • Glycopyrrolate up to 400μg IV
    • Adrenaline infusion 2 - 10μg/min IV
    • Isoprenaline infusion 5μg/min IV
    • Transcutaneous pacing

Venous air embolism

  • More common if the dural venous sinuses are opened, especially if the head is elevated above the heart
  • Use of hydrogen peroxide as a haemostatic agent can also cause oxygen embolus
  • The most sensitive method of detecting VAE is TOE, but the most sensitive non-invasive method is precordial Doppler

  • Attempting CPR or defibrillation with the patient's head pinned can lead to injury of the scalp, skull or C-spine
  • The Mayfield clamp has a quick-release lever, which should be engaged prior to starting CPR
    • This releases the clamp from the table although the pins are still in situ (and should remain so to avoid precipitous pin-site bleeding)
    • There have been no case reports of pin-site burns injury during defibrillation with the pins in situ
    • The surgeon should support the patient's head during CPR

  • If defibrillation is required, ensure:
    • Nobody is touching the patient
    • The 'horse-shoe' type head support is used or the patient is moved to provide adequate head support

CPR and defibrillation in different positions

  • If supine → chest compressions ± defibrillation without changing position

  • If prone → initially chest compressions ± defibrillation without changing position
    • May actually generate better MAP than anterior compression
    • Pillows or blankets may be required to support the abdomen e.g. if on a Montreal mattress
    • Pad positioning should be:
      • Posterolaterally (left mid-axillary line + over right scapula)
      • Bi-axillary
    • If ineffective chest compressions, supinate patient onto another bed

  • Lateral (inc. park bench) → move into supine position prior to commencing chest compressions ± defibrillation
    • AP pad positioning prior to moving may help effectiveness of defibrillation

  • Sitting → move into supine position prior to commencing chest compressions ± defibrillation

Surgical considerations

  • Eliminate surgical causes e.g. dural retraction, instrumentation
  • Flood site with saline to eliminate further air entrainment if VAE suspected
  • Tip patient head-down if VAE suspected

  • Control haemorrhage, protect against trauma and minimise wound contamination

Specific considerations

  • The dose of adrenaline is 50 - 100μg boluses IV rather than the standard 1mg
  • Once a total 1 mg dose has been reached without ROSC, subsequent doses of 1 mg should be given in alternate cycles according to the adult ALS algorithm

  • Use TTE to check for VAE