Carotid Endarterectomy

OVERVIEW

Carotid Endarterectomy = removal of atheromatous plaque from the ICA. Artery clamped, open, plaque stripped and then closed directly or with a Gore-Tex vein patch.

PREOPERATIVE ASSESSMENT

Indication

  • >70% stenosis in symptomatic TIA or CVA patients
    -> incidence of death or major CVA = 2-5%

Issues

  • control hypertension to 160/90
  • often are elderly with all the co-morbid conditions associated with vascular disease (HT, hyperlipidaemia, IHD, PVD, previous CVA’s or TIA, DM, smoking, COPD)
    -> if this is an elective procedure then time to medically optimize these problems is indicated
  • often have bilateral carotid disease
    -> discussion with surgeon whether carotid shunt required intraoperatively or whether there is sufficient co-lateral flow from the other carotid artery to provide cerebral perfusion, also whether stump pressure is required (extra attachment for the arterial line)
  • document pre-existing neurological deficits so new ones can be easily assessed
  • note preoperative BP as this and above will be intraoperative target

Appropriate preoperative investigations

  • bloods
  • ECHO for associated valve disease and LV function
  • ECG – signs of LVH or arrhythmias
  • Group and Hold – in case significant bleeding take place

MANAGEMENT

Intraoperative Management

  • supine, head up
  • arterial access for invasive monitoring before induction (sited under LA and on contralateral side to operation)
  • large bore IV access for rapid infusion of vasopressors and fluid if required
  • may site a superficial +/- deep cervical field block to decrease intraoperative anaesthetic requirement
  • have vasopressors drawn up and lines primed (phenylephrine, metariminol, ephedrine) and vasodilators (GTN, labetalol)
  • monitoring; 5 lead ECG, arterial line, NIBP, SpO2, ETCO2

GA

  • balanced induction maintaining normal haemodynamics -> catastrophic blood pressure drops may produce watershed infarct, hypertension can causing a haemorrhagic CVA
  • securing airway; use an endotracheal tube as have limited access to airway intraoperatively (abate hypertensive response to entubation using short acting opioid, LA to cords or vasodilators such as GTN or SNP)
  • ventilate with IPPV to maintain a normal PaO2 and PaCO2 -> optimize cerebral blood flow
  • remifentanil infusion is a good agent for rapid waking post-operatively
  • close monitoring and haemodynamic management around time of clamping of carotid (may produce brady-arrhythmias with hypotension)
    -> maintain BP @ 20% above base line
  • measure stump pressure (if stump pressure within range of MAP then shunt not needed otherwise surgeon will insert)
  • other techniques to monitor cerebral function under GA (EEG, somatosensory evoked potentials, transcranial Doppler of MCA, near-infrared spectroscopy)
  • once graft in and closing monitor for bleeding
  • minimal analgesia required if field block used as surgery is superficial
  • smooth emergence and extubation with no coughing as this can increased pressure inside carotid and blow graft -> expanding haematoma
  • monitor operative site for haematoma

LA

  • benefits = ability to monitor neurological function closely and treat if deteriorates @ carotid cross clamping (shunt or drive pressure up)
  • can use remi or propofol sedation for incision and dissection -> turn off when carotid clamped
  • monitor patients speech, contralateral arm strength and cerebration -> if neurology doesn’t respond to shunt or increasing BP then convert to GA with LMA
  • once graft in and closing monitor for bleeding
  • minimal analgesia required if field block used as surgery is superficial

Post-operative Care

  • examine for neurological deficits
  • ask surgeons what BP targets they would like to aim for
    (may require perioperative vasopressor infusion -> may require an HDU bed also monitoring for hypertension and reperfusion haemorrhagic CVA)
    -> HDU optimal
  • cervical haematoma with airway compromise needs to be monitored for -> immediate re-exploration if airway obstruction developing (remove sutures in recovery to allow drainage before intubation)

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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