EVAR:

 

Surgery issues:

Patient selection

·      Ideal if very old, very comorbid

·      Lower early mortality rate

·      Same 2 year mortality rate

·      Endoleak very common after a few years

Difficulty

·      Duration highly variable

·      Conversion to open 1/100

Complications

·      Renal failure (contrast ++)

·      Spinal cord infarction

·      Endoleak (very common after a few years)

 

Anaesthesia issues:

Surgical conditions

Require immobility + periodic apnoea

·      If <2h: spinal + sedation

·      If >2h: relaxant GA

Anticoagulation

·      Initiation: heparin e.g. 5000 units

·      Monitoring: ACT

·      Reversal: protamine (rarely at St V)

Renal protection

High risk due to contrast

 

Risk factors:

·      Patient: CKD, heart failure, T2DM, renovascular disease

·      Surgery: recent contrast, long clamp time, renal artery disruption

·      Anaesthesia: hypoperfusion, nephrotoxins, massive transfusion

Preserve the vessels

·      Fenestrated graft

·      Re-anastomosis

Preserve perfusion pressure:

·      ↑mAP: volume + pressor

·      ↓CVP: cardiac function

Things that don’t work:

·      Dopamine (renal dose 1-3mcg/kg/min)

·      Mannitol

·      Frusemide

·      NAC

·      Methylprednisolone

Spinal protection

High risk due to branch occlusion

 

Risk factors:

·      Patient: not sure

·      Surgery: affects lumbar arteries, artery of Adamkiewicz

·      Anaesthesia: hypoperfusion

Monitoring:

·      MEP

·      SSEP

Preserve the vessels:

·      Fenestrated graft

·      Re-anastomosis

Preserve perfusion pressure:

·      ↑mAP: volume + pressor

·      ↓CVP: cardiac function

·      ↓CSF pressure: insert lumbar drain pre-op if high risk

 

Plan:

Anaesthesia

·      Relaxant GA

Airway

·      ETT

Access

·      2 x large IVC

·      A-line

·      CVC

Monitoring

·      Sat probe

·      NIBP

·      ECG 5 lead

·      ABP + PPV

·      IDC

·      NMT

·      Gas analysis

·      ACT

Drugs

Induction:

·      Midazolam 0.025mg/kg

·      Alfentanil 10mcg/kg

·      Propofol 2mg/kg

·      Cisatracurium 0.1mg + atracurium 0.5mg/kg/h
(facilitates periodic apnoea)

·      Metaraminol 50-100mcg/kg/min

Maintenance:

·      Sevoflurane 1.5%

·      Fentanyl 0.5-1mcg/kg PRN

·      Metaraminol 50mcg/kg/min PRN

 

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