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Neuroanaesthesia 2008

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Early postoperative complications after intracranial surgery Stenting or endarterectomy for carotid stenosis. Neuroanaesthesia for the pregnant patient Decompressive craniectomy Awake craniotomy Visual loss after spinal surgery

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Early postoperative complications after neurosurgery

Hypertension Shivering CBF changes

Hypertension

Recovery from GA Pain Restlessness Strain/coughing Raised ICP Primary arterial hypertension 70% of patients

Shivering

Occurs in 40% of patients with T < 36.5 Less frequent after propofol than volatiles Increases VO2 by approx 40% (not 400%).

Treatment of hypertension

Beta-blockade (ideally labetalol but not registered in Australia GTN (causes cerebral vasodilatation) Analgesia (risk of hypercapnia)

In the following two figures, Group I includes patients extubated at the time of the conclusion of anaesthesia. Group II patients were sedated for a further 30 min (with propofol) before they were extubated.

Oxygen Consumption during early and late Extubation

Stress Markers during early and late Extubation

Early awakening Delayed awakening Advantages

*Earlier examination (and re-intervention) *Less hypertension *Less catecholamine burst *Lower costs

Advantages

*Less risk of hypoxia *Better cardio-respiratory control *Better late haemostasis *Temperature control

Anest Analg 1999; 89: 674-8

Early awakening Delayed awakening Disadvantages *Hypercapnia/ *Hypoxia *Hypothermia Disadvantages *Difficult examination *Sympathetic stimulation

Anest Analg 1999; 89: 674-8

Stenting or Endarterectomy for Carotid Artery Stenosis?

CEA efficacy well established in symptomatic patients with > 70% stenosis. Generally accepted morbidity/mortality: Any stroke and death 4.5% Death 1.1% AMI 2%

CAVATAS* Trial. Lancet 2001; 357: 1729-36.

Endovasc Number of patients Mean age Mean % stenosis Periop stroke Day-of-Surgery stroke 240 67 86 9% 6.3% CEA 246 67 85 10% 6.4%

*Carotid And Vertebral Artery Transluminal Angioplasty Study

CAVATAS Trial. Lancet 2001; 357: 1729-36.

Endovasc New strokes during 2 years follow-up Severe re-stenosis after one year 6 CEA 10

18%

5%

NEJM 2006; 355: 1660-71

CEA or stenting?

Hypothesis: Stenting as good as (not inferior to) CEA 537 symptomatic patients with > 60% stenosis Primary end-point: Any stroke or death within 30days

CEA or stenting?

Stroke within 30 days: CEA group Stented group 3.9% 9.6%

CEA or stenting?

NEJM 2004; 351: 1493-1501

Protected stenting vs CEA in high-risk patients High-risk factors: Symptomatic stenosis > 50% Asymptomatic stenosis > 80% Contralateral occlusion Severe C-P disease Previous neck surgery Age > 80 years

End points

CEA or stenting?

CEA

Incidence

Stent

Death/Stroke/MI within 30 days Death/Stroke within 1 year

}

20% 12%

NEJM 2004; 351: 1493-1501

Conclusion

Stenting is as good as CEA for - symptomatic stenosis in - high-risk patients

NEJM 2004; 351: 1493-1501

This initial report from RPH described the use and outcome of stenting for 53 high-risk patients, which years later turned out to be the right patient population for this procedure.

Radiology. 2001 Sep;220(3):737-44

Neuroanaesthesia for the Pregnant Patient Management of SAH in pregnant patients: 7% of maternal mortality Treatment as for non-pregnant patients

Wang et al. Anest Analg 2008; 106:

Neuroanaesthesia for the Pregnant Patient Considerations in theatre: Pt in Right or Left lateral position for long operations (> 1hr.) Fetal heart monitoring useful after 26 weeks Tramadol used rarely Neuraxial block often unwanted by surgeon

Wang et al. Anest Analg 2008; 106:

Neuroradiology for the Pregnant Patient Maximal acceptable maternal dose: "Safe" fetal dose Fetal exposure: Coiling of aneurysm Cerebral angiography 1 rem 0.5 rem

0.3 rem 0.1 rem

1 rem = 10 mSv

Wang et al. Anest Analg 2008; 106:

Neuroanaesthesia in Pregnancy ­ Anaesthetic Drugs in the Perioperative Phase

Antacids ­ Long safety record (Ranitidine) Propofol ­ Acceptable alternative to thiopentone for CS Remifentanil - 1µg/kg at induction (for BP) Oxytocic drugs ­ Oxytocin OK, avoid ergometrine Magnesium ­ 50mg/kg after induction to reduce BP

Wang et al. Anest Analg 2008; 106:

Decompressive Craniectomy

Trepanation (Trephination) is perhaps the oldest surgical procedure for which there is evidence, and in some areas may have been quite widespread. Out of 120 prehistoric skulls found in France dated to 6500 BC, 40 had trepanation holes. Surprisingly, many survived their operation!

Wikipedia 2008

Decompressive Craniectomy

Epidural haematoma?

Decompressive Craniectomy

Decompressive craniectomy is used in around 3% of patients with trauma brain injury. Re-implantation occurs after 6-12 weeks

J Neurosurg 1999; 90: 187-96

Decompressive Craniectomy

Part of German treatment protocols since 1970's. Bone flap preserved in abdominal fat before 1994. Now one of the 3rd tier therapies in the American Guidelines of Mx of Head Injury

J Neurosurg 1999; 90: 187-96

Decompressive Craniectomy

487 patients with GCS < 8 randomised to Trauma Craniotomy (12 x 15 cm) or Standard Craniotomy (6 x 8 cm)

J Neurotrauma 2005; 22: 623-8

Decompressive Craniectomy

Outcome: Trauma Crani 40% 26% Standard Crani 29% 35%

Good Death

J Neurotrauma 2005; 22: 623-8

Decompressive Craniectomy

Current Brain Trauma study in ICU: DECRA-Trial. Multicentre, international study of Craniectomy

vs.

Best current non-surgical treatment for uncontrollable, intracranial hypertension

Awake Craniotomy

Mesial side of temporal lobe Adjacent to speech centre Variable location. Often adjacent to motor cortex

Indications:

Epilepsy surgery:

Tumor surgery:

Anaesthesia for Awake Craniotomy

CJA 1988: 354 patients for AC for epilepsy 1976-1983: Droperidol and fentanyl Doses: 10mg (1-40) 6µg/kg (1-24)

CJA 1988; 35: 338-44

Anaesthesia for Awake Craniotomy

1976-83

Problems: Conversion to GA 2% Seizures 16% Nausea / Vomiting 8% Excessive sedation 3 %

CJA 1988; 35: 338-44

Anaesthesia for Awake Craniotomy

> 2000: Propofol and fentanyl / remifentanil. "Evolution of a technique to facilitate awake neurological testing".

BJA 2003; 90: 161-5.

Group A Fent Midaz Prop inf. Sp Vent

Group B Fent Prop inf. LMA Sp Vent

Group C Remi Prop TCI LMA Con Vent

Anaesthesia for Awake Craniotomy

Complications (% of each group): Gr A Pain Excessive sedation 0 Airway obstruction 7 Hypercapnia Hypotension 0 Hypertension 0 Deficit Gr B 70 3 0 100 6 11 8 Gr C 0 5 0 0 21 0 5

BJA 2003;90:161-5

Anaesthesia for Awake Craniotomy

An "Asleep ­ Awake ­ Asleep" technique with TIVA and controlled ventilation. Thorough preoperative preparation with detailed explanation of the course of anaesthesia is important.

Anaesthesia for Awake Craniotomy

Pharmacological premedication: Usual anti-epileptic medication No sedatives Give antiemetic(s) and H2 antagonist

Awake Craniotomy

Intravenous induction LMA insertion A-line insertion IDC insertion Local anaesthesia administration (surgeon) Mayfield frame Craniotomy

Anaesthesia for Awake Craniotomy

Cease remifentanil and propofol infusions in liaison with surgeon. Remove LMA when pt awake. Awake period with stimulation: Give thiopentone or diazepam if seizures occur. Re-start infusions. Insert LMA.

crani.avi

Visual loss after spinal surgery

Incidence: Approximately 1 : 1,000 anaesthetics in the prone position

Visual loss after spinal surgery

> 6.5 hours < 80mmHg systolic or < -24% of baseline mean > 44% of TBV No defined lower limit

Risk factors:

Prolonged procedures:

Prolonged hypotension:

Massive blood loss

Severe anaemia:

Head in neutral position No neck flexion/extension /rotation Head higher than heart No direct external pressure of the eyes

Summary

-blocker for post-craniotomy hypertension during early extubation. Carotid stenting for select, high-risk patients. Rx of SAH in pregnancy same as for nonpregnant. Decompressive craniectomy for uncontrollable intracranial hypertension. Awake craniotomy = Asleep-Awake-Asleep. Visual loss: "Avoid hypotension and hypoxia"

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Microsoft PowerPoint - Neuroanaesthesia 2008 edited