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Anaesthesia for vascular surgery.

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Anaesthesia for vascular surgery. Speaker: Dr. Pragati Moderator: Dr. Madhok. www.anaesthesia.co.in anaesthesia.co.in_at_gmail.com Anaesthesia for emergency sx. – PowerPoint PPT presentation

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Title: Anaesthesia for vascular surgery.


1
Anaesthesia for vascular surgery.
  • Speaker Dr. Pragati
  • Moderator Dr. Madhok.

www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
m
2
  • Elective vascular surgeries are performed for
    ischemic symptoms resulting from atherosclerotic
    occlusive disease of internal carotid, aortoiliac
    and femropopliteal arteries.
  • Emergency surgeries are done for rupture of
    aorta, cause being atherosclerotic aneurysmal
    disease or acutely thrombosed femoral trees.

3
Atherosclerosis
  • Risk factors DM,HTN, age,smoking, lipid
    metabolism abnormalities, high homocysteine or
    fibrinogen levels.
  • PATHOGENESIS
  • Vascular endothelial injury
  • Increased superoxide anion generation.
  • Decreased nitric oxide generation.
  • Release of chemokines and adhesion molecules
    attract monocytes,which accumulate lipid and
    become foam cells.
  • Fatty streak develops leading to irregulariy of
    intima,which attracts platelets.
  • PDGF induce smooth muscle proliferation and
    formation of fibrous plaque.

4
                                             
                                             
                                             
5
Medical Therapy
Drug Side Effects Recommendation
Aspirin Bleeding, ? GFR Continue until day of surgery.
Clopidogrel Bleeding, TTP Hold for 7 days before surgery.
HMG CoA reductase inhibitors (statins) LFT abnormalities, Rhabdomyolysis LFT, Continue through morning of surgery. Check CPK if myalgias
6
Beta blockers Bronchospasm Hypotension Bradycardia, continue
ACE inhibitors Induction hypotension, cough Consider one half dose on day of surgery.
Diuretics Hypovolemia, electrolyte abnormalities Monitor fluid and urine status
Calcium channel blockers Hypotension with amlodipine continue
Oral hypoglycemics Hypoglycemia, Lactic acidosis with metformin Switch over to insulin, Monitor glucose.
7
Neuroaxial Anaesthesia in patient receiving
thromboprophylaxis
Antiplatelet Medications Discontinue Ticlopidine 14 d Clopidogrel 7 d GP IIb/IIIa 8-48 hr in advance
Subcutaneous UFH Needle placement 4 hr after heparin Heparin 1 hr after Needle placement or Catheter removal
Intravenous UFH Needle placement / catheter removal 4 hr after discontinuing, heparinize 1 hr after neuraxial technique, delay 6 hr if traumatic.
8
LMWH Neuraxial technique 12 hr after LMWH first postop dose 4-12 hr, catheters removed 10-12 hr after LMWH and 4 hr prior to next dose postpone LMWH 24 hr if traumatic.
WARFARIN INR lt 1.5 for performance of neuraxial techniques and catheter removal.
9
Major Vascular Reconstruction
  • High risk surgery in high risk patients
  • Mortality 5 (mostly cardiac)
  • An opportunity to identify and treat significant
    cardiac disease
  • May be the patients first time for such
    assessment

10
  • The Conventional Question
  • Which patients need further evaluation or
    treatment for coronary artery disease ?
    But, No evidence that CABG
    prior to non-cardiac surgery reduces mortality

11
  • Risk assessment methods
  • Clinical
  • Non-invasive tests
  • Invasive tests

12
  • Stress ECG
  • First choice in the Ambulatory patient
  • More sensitive than a resting ECG
  • 50 vascular patients can
    not attain adequate HR
  • Assesses functional capacity
  • Cost effective

13
t
  • Nuclear Perfusion Imaging
  • Dipyridamole/Adenosine Thallium scanning
  • Mimics exercise
  • Useful when patients cannot
    exersise.
  • Most common non-invasive
    test
  • Relatively costly.

14
  • Coronary Angiogram
  • The Gold Standard

15
u
  • ETTStress Mangano 1999
  • ECG

16
Risk reducing strategies for MI
Periop Beta-blockade 30 days before surgery and continuing. Class I
Alpha-2- agonists Clonidine 300 ?g 90 min before Sx, continue OD-3 days. Class II A
Statin Atrovastatin 20 mg OD 45 d prior and after surgery 2 wks. Class I
ACE inhibitors Decreased stroke rate, ? mortality, stabilize plaque Class II B
CCB ? Peri op cardiac events. (SVT) Class II B
NTG Suspected coronary vasopasm, treat hypertension Class III
17
Perioperative myocardial infarction
  • Detection 1. ECG
    2.Periop Holter monitoring.
    3.TEE.
    4.creatine kinase myocardial
    band isoenzyme.
    5.Cardiac troponins.
    MANAGEMENT mc in 1st
    24 hrs.after sx. Stable coronary syndrome occur
    with increased oxygen demand,in setting of fixed
    coronary plaques.

18
  • Unstable ischemic syndrome caused by rupture of
    plaque with local thrombus and vasoreactivity.
  • Anaesthetist can control Tachycardia,hypertensio
    n/hypotension, anemia, hypothermia and shivering,
    inadequate analgesia, hypoxia.
  • High dose narcotic anaesthetics reduce stress
    response and improve outcome.
  • Epidural analgesia reduce periop MI.
  • Postop sufetanil infusion reduces severity.
  • In patients with evolving MI, intra aortic baloon
    pump can improve coronary blood flow and decrease
    afterload.

19
Other medical problems.
  • Hypertension increase chances of cerebral bleed
    and intraop hypotension.
  • DM risk of PVD,exacerbate neurological injury,
    maintain glult150mg/dl.
  • Hypercagulable states more common postop, in pts
    of PVD,deficient protien C,S antithrombin and
    HIT. Rxstop heparin, anticoagulate with
    Argatroban and 3wks of coumadin.
  • Tobacoo abuse FEV1lt2L/sec pulmonary
    complications pneumonia, post op ventilation,
    ARDS.
  • Renal insufficiency postop renal faliure,
    dialysis, hyperkalemia.

20
CAROTID ENDARTERECTOMY
  • Carotid a. disease atherosclerotic plaque at
    bifurcation.Thrombosis is likely to occur. 1 or 2
    TIAs/RINDsamaurosis fugax, episodes of
    clumsiness,speech problem etc. occur frequently
    before final stroke.
  • surgical approaches
    1. carotid endarterectomy.

    2.percutaneous transluminal angioplasty and
    stenting.
  • Goal for anaesthetist maintain cerebral
    perfusion.

21
  • PREOP EVALUATION
    H/O DM, HTN, age, tobacco abuse,
    dislipidemia,CAD. Asprin/clopidogril intake.
  • All blood reports,cadiac tests,cerebral
    angiography size, morphology of plaque and
    associated cerebral or aortic disease.

22
  • MONITORING

  • ECG lead 2 and v5, pulseoximetry,
    etco2,temperature probe, IABP,CVP not put bcoz
    of risk of carotid puncture.
  • Neurological monitoring
    1.Electrical integrity EEG,SSEP,AEP.
    2.Flow velocities and embolism detection
    transcranial doppler.
    3.Perfusion stump pressure,
    cerebral oximetry,juglar venous oxigenation.

23
Intra operative concerns
  • Maintain stable high normal BP to maitain
    cerebral perfusion.
  • Maintain normocarbia/moderate hypocarbia
    hypercarbiasteal phenomenon


  • use NS as IVF.
  • Brain protection during regional ischemia
    thiopentone/ propofol/ etomidate. Hypothermia.

24
  • Prevention of reperfusion injury
    nimodipineCCB, steroids.
  • If collateral flow is compromised or B/L carotid
    disease or complex procedure SHUNT is used.
    problems with shunt embolisation of atheroma,
    air embolism, kinking of shunt,disruption of
    artery.

  • Ensure adequate heparinisation heparin
    50-100u/kg. maintain ACTgt300sec.
  • As surgeon approaches carotid sinus sudden
    bradycardia and hypotension occurs,baro-receptor
    reflex.surgeon shuld infilterate bifurcation
    with 1 lignocaine.

25
Regional anaesthesia
  • Sensory blockade of C2 C4 dermatomes is needed.
    Superficial and deep cervical block or
    subcutaneous infilteration of surgical field.
  • Advantages pt. as cerebral monitor, stability of
    blood pressure, inexpensive, avoidence of GA
    induced cardiorespiratory depression.
  • Disadvantages requires highly cooperative
    pt.,pharmacological brain protection cant be
    given,surgeons preference,difficult to protect
    airway in seizure/loc/panic.

26
Postoperative management
  • 1. Hyperperfusion syndrome result from increased
    CBF. Ipsilateral headache /seizures. Rxsteroids.
  • 2.Hypertension Can lead to MI, cerebral odema,
    stroke, neck haematoma. Rx labetalol,NTG,
    esmolol.
  • 3.Hypotension and bradycardia bcoz of
    baroreceptor exposed to high transmural pressure.
    Adjust in 12-24hrs.
  • 4.postop respiratory insufficiency caused by
    recc. larangeal/ hypoglossal n. injury,
    defficient carotid body function , neck haematoma.

27
Aortic reconstruction.
  • Aneurysmal disease-ever present threat to life.
  • Risk of rupture diameter of aneurysm.gt5cm,greate
    r risk.
  • Sx.-
  • Endovascular

  • Open -Trans / retroperitonial
  • approches.
  • Expected blood loss 500 to gt2 Lts.

28
Pathophisology of aortic occlusion.
  • 1.CVS changes inc afterload,renin
    activation,catecholamine release-VC.
  • Shift of blood vol. proximal to clamp inc.
    preload, inc ICP, inc. lung blood volume.
  • Level of clamping affects- Infrarenal clamping is
    well attenuated by compliant splanchnic
    vasculature.
  • 0.5mcg/kg of nitroprusside offsets the effects.
  • Unclamping- sev. Hypotension and reperfusion
    injury Rx CaCl2 , gradual unclamping, mannitol.

29
2. Renal haemodynamics.
  • ARF- m/c post suprarenal clamping. Even with
    infrarenal- 70 reduction in RBF.
    Renal protection
    good hydration, mannitol, dopamine, fenoldopam.
  • 3.PULMONARY COMPLICATIONS pul. Odema result
    from inc PVR and sequesteration of neutrophils.

30
  • 4.BOWEL ISCHEMIA hypoxic insult and bacterial
    translocation-25 mortality. Rx methyl
    prednisolone at induction is beneficial.
  • 5.CNS/SPINAL CORD ISCHEMIA Radicular a. of
    Adamkeiewicz and hence ant. Spinal a.
    Preventive stratigies fast Sx, short clamping
    time, maintain normal cardiac function and high
    perfusion pressure.

31
Management of aortic surgery
  • Monitoring ECG,IABP, SpO2, CVP / PCWP, UO.
  • Induce anaes. With small doses of Propofol with
    judicious amt. of Esmolol, lignocaine.
  • For thoracic aneurysm, bronchial blockers are
    advantageous as they allow postop ventilation.
  • Half hour before clamping reduce fluids.

  • At time of clamping- VD drug/ Vol. anaes. Is
    inc./ PEEP just before clamping.

32
  • For thoracic level occlusion- SC perfusion is a
    concern. Accept proximal HTN, ensure adequate
    volume,maintain BP by light anaes,BT and
    endogenous vasoconstrictors.
  • Autotransfusion devices can be used. Immediately
    before unclamping allow BP and filling pressures
    to rise high, continue volume replacement ,
    Mannitol 0.5 to 1.0 g/kg .
  • During emergence and postop NTG/Esmolol infusions
    and maintain HRgt55bpm and BPgt110mmhg.

33
Endovascular surgery
  • Technique involves delivery of grafts PTFE/
    dacron through a catheter in Femoral a.
  • Goals of anaesthesia
  • 1. Preserve organ function
  • 2. At time of deployment,mild hypotension and
    lack of patient movement.
  • Preimplantation angiography is required.
    Before Dye inj. Pretreat pts. With Fluid and
    N-acetylcysteine .
    Complications of endovascular Sx are
    lower less blood loss, less ICU stay. Paraplegia
    may occur Rx induced HTN and CSF drainage. Be
    prepared for rupture, Vs. injury and embolic
    ischemia.

34
Anaesthesia for emergency sx.
  • For ruptured AAA- retroperitonial
    hemorrhage-pain,faintness,vomiting, pain in back/
    abdomen, shock.
  • Prefer awake intubation/RSI with Etomidate in
    uncooperative pts.
  • Replace volume and blood. Secure 14G catheter .
    Use fluid warmers.
  • Once aorta is controlled,CVP and TEE probe can be
    put.
  • If shock is resistant to dopamine/ epinephrene/
    Norepinephrine- Vasopressin should be used.
  • Pts. Are often acidotic- Sodabicarb and increased
    ventilation should be used.
  • Maintain temperature, hematocrit and coagulation.

    Primary goal is to control blood loss, maintain
    BP and then preservation of myocardial function.

35
Lower extremity revascularisation
  • C/C claudication,ischemic rest pain, ulceration,
    gangrene. Goals of
    anaesthetic management
    1. prevent cardiac complications.
    2. prevent hypercoagulation
  • response to sx.
    3. ensure adequate perfusion.
    4. maintain graft patency.

36
  • Endovascular repair Angioplasty/ stenting.
    Drug eluting stents
  • release Paclitaxel and prevent restenosis.
  • Vascular reconstruction procedures inflow
    reconstruction Aortoiliac/ Aortofemoral bypass.

    Outflow reconstruction Fempop.
    Saphenous vein and cryopreserved umbilical v.
    show better patency than PTFE grafts.

37
Anaesthetic management
  • Monitoring IABP,CVP,U/O.
  • Pay close attention to temparature, Oxygen
    delivery, haemodynamic homeostasis and Pain
    relief.
  • Two major disadv. Of regional anaes. are risk of
    CHF autotransfusion and epidural haematoma.

38
Regional V/S GA
Anaes.Tech Advantages Disadvantages
Regional Effective stress response blockade. Patient as monitor. Improved graft BF. No post op hypercoagulability. Postop. Analgesia Prevent chronic pain syndromes. Improved cardiopul. morbidity Time consuming. Technically difficult Inadequate for the surgery. Pt. discomfort in long cases Sympathectomy requires vol. loading. Resp. depression. Neurological sequelae. Precludes thrombolytic Rx.
General Controlled airway Hemodynamics easily controlled Reliable Patients comfort in long cases. Hyperdynamic state after surgery Fluctuations in catecholamine levels. Postop. Hypercoagulability. Greater perturbation of resp. mechanics.
39
Anaesthesia for emergency peripheral vascular Sx.
  • Pulseless ,cold, numb extremity, paresthesias,
    sensory/motor loss.
  • Cause

    if embolic Fogarty embolectomy.
    If ThromboticBypass
    reconstruction.
  • Risks blood loss, Inc. potassium and myoglobin,
    compartment syndrome.
  • Free radical scavengers-Mannitol and N-acetyl
    cysteine should be given at time of reperfusion.

40
Thank You
www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
m
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