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Anaesthesia for intracranial SOL , including vascular surgeries

Anaesthesia for intracranial SOL , including vascular surgeries. Dr. Megha Aggarwal. University College of Medical Sciences & GTB Hospital, Delhi. Outline. Introduction to SOL Classification Presentation Management strategies Neuroanaesthetic goals Hemodynamic concerns

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Anaesthesia for intracranial SOL , including vascular surgeries

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  1. Anaesthesia for intracranial SOL, including vascular surgeries Dr. MeghaAggarwal University College of Medical Sciences & GTB Hospital, Delhi

  2. Outline • Introduction to SOL • Classification • Presentation • Management strategies • Neuroanaesthetic goals • Hemodynamic concerns • Conduct of anaesthesia • Pre anaesthetic assessment • Monitoring • Induction, maintenance and emergence • Post-operative concerns

  3. Classification of SOL

  4. Neoplasms

  5. Common SOLs 1. Meningioma- 90% supratentorial 5-6th decade benign Highly vascular with large feeding vessels 2. Gliomas - most common 1⁰ intracranial tumors slow growing astrocytomas to malignant glioblastomas seizures, focal deficits, ↑ ICP as per tumour type

  6. Common SOLs (cont …) 3. Tumors of ventricular system Choroid plexus papillomas, ependymomas, Obstructive hydrocephalus, midbrain compression 4. Metastatic Most common intracranial tumors Multiple 5. Intracerebral abscess Frontal sinus, middle ear, blood born, foreign body Meningitis , ↑ ICP

  7. How do they present ?

  8. Herniation / midline shift • HTN , • Tachy/ bradyarrythmias, • 3 & 6th CN palsy (I/L pupil dilation + no light reflex), • C/L hemiplegia/ paresis, • Coma , • Resp arrest

  9. Goals of anaesthesia • Preserve both injured & uninjured cerebral territories by global maintenance of cerebral homeostasis. • Maintain normocarbia, normotension, normoxia, euthermia, euglycemia. • Avoid secondary brain insults • Optimizing operative conditions to facilitate resection

  10. Anaesthetic implications Depending on type (vascularity) and location (supra/ infratentorial) of tumor Infratentorial Air embolism Care during vital structure handling Positioning Higher mortality Supratentorial ICP management Monitoring brain function Massive intraoperative hemorrhage Seizures Air embolism (if venous sinuses traversed)

  11. Secondary insults

  12. WHY CONTROL BP ? • AVM/ aneurysm/ head injuries/ tumors • Disruption of cerebral autoregulation • BP fluctuation poorly tolerated • ↑BP – Vasogenic edema, ↑ tumor / aneurysm size, aneurysmal rupture • ↓ BP – Ischemia/ infarction

  13. Stimuli for BP fluctuation Laryngoscopy Intubation Positioning Suction Skeletal fixation of head Preventive measures Deep plane of anesthesia Additional dose of iv anesthetic agent Adequate muscle relaxation Lignocaine (1.5 mg/kg) Esmolol (0.5 – 1 mg/kg)

  14. Preoperative assessment • INVESTIGATIONS • EXAMINATION • HISTORY Assessment & documentation

  15. Preoperative assessment • HISTORY • Level of consciousness • Seizures - ↑ CMRO2 , ↑ ICP • ↑ ICP – headache, vomiting, without nausea, blurred vision, ocular palsy (CN 6) • Hydration – fluid intake, NPO status, diuretics, SIADH • Medications – steroids, antiepileptic drugs, aspirin/ clopidogrel, diuretics, mannitol • CN palsies- dysphagia, laryngeal dysfunction • Associate systemic illness- • Cardiac – HTN (hypotensive anaesthesia) • Respiratory • Renal – intraoperative mannitol and diuretics, SIADH, DI

  16. Preoperative assessment • EXAMINATION • Mental status, level of consciousness (GCS) • Hydration status • Systemic examination a) CNS • ↑ICP – papilloedema, cushing response (↑BP, ↓HR), suturaldiastasis, bulging fontanels. • Focal signs (CN palsies) - Dysphagia, strabismus, focal seizures, speech deficit, motor & sensory examination. • Midline shift - I/L Pupillary dilatation and absent light reflex (3rd CN)

  17. Preoperative assessment • EXAMINATION b) Respiratory- effect of positioning, resp. pattern, neurogenicpulm. edema c) CVS – Cushing reflex, HTN (resets limits of cerebral autoregulation), BP (cerebral perfusion) d) GI -↑ Aspiration (steroids, ↑ ICP , low GCS, emergency) e) Renal - ↓fluid intake, diuretics, mannitol, SIADH, DI f) Paraneoplastic syndromes

  18. Preoperative assessment • INVESTIGATION • Complete blood count – Hb, TLC, Platelet count • RBS – hyperglycemia – cerebral edema , ↑ischemic brain injury • KFT – urea, Na, K • Coagulation profile • ECG – ischemic changes, arrhythmias • CXR

  19. Preoperative assessment • INVESTIGATION 7. CT/ MRI – tumor assessment Location – silent/ eloquent area Size – degree of compromise of intracranial dynamics including auto regulation. Ventricular distortion / CSF obstruction Midline shift Perilesional edema - makes tumor functionally bigger Contrast enhancement - degree of BBB disruption Proximity to venous sinuses - blood loss

  20. ASA physical status ???? • Nature of surgery • High incidence of systemic involvement – CN palsies, motor/ sensory involvement • Higher comorbidities • Poor surgical outcome

  21. Premedication 1. Sedation -Risk assessment, individualised - often avoided 2. Others - Continue anticonvulsants, antihypertensives, steroids till morning of surgery - mannitol, furosemide Sedation - hypoventilation (hypercapnia, hypoxia, airway obst ) Sedation - ↓stress→↓ICP→↓ vasogenic edema

  22. Vascular access 1. Intravascular a) 2 large bore i.vcannulas b) CVP -VAE (diagnostic + therapeutic ) - vasoactive drugs 2. Arterial canulation a) NIBP (anticipated blood loss) b) ABG c) Hypotensive anaesthesia

  23. Monitoring • ECG, HR – myocardial ischemia, arrhythmias • SpO2 • ETCO2 • NIBP/ IBP – at level of operative field • NMT – on non hemiplegic limb • Temperature • CVP • Urine output • Precordialdoppler, TEE, ETN2 • ICP – currently rarely used, except in neurotraumatology

  24. Induction GOALS – Normotension, Normocarbia, Normoxia Preoxygenation P/M – opioid (fentanyl 1-2 μg/kg , morphine 0.1 mg/kg) Lignocaine , Esmolol, 2nd dose of i.v induction agent 60-90 sec earlier I/W – Thiopentone (3-5 mg/kg) Propofol (1.5 – 2.5 mg/kg) Myorelaxation – Sch (transient ↑ ICP) Use intermediate acting relaxants Atracurium – histamine release ( cerebral vasodilatation) Vecuronium, Rocuronium – commonly used Only after adequate muscle relaxation achieved, perform quick + gentle laryngoscopy Intubation – armoured ETT Tape on opposite side of surgery Bandaging may ↓cerebral venous return Controlled ventilation

  25. Positioning GOAL- Slow and gentle positioning with 15- 20⁰ head up tilt to aid cerebral venous drainage • Verify cautiously – 1. All potential pressure points padded • 2. Eyes protected & padded • 3. Peripheral pulses palpable • 4. Nerve compression absent • 5. Ventilation adequate ( PEEP, ETT position) • ETT – Kinking in post. Oropharynx • Advancement / extubation • Neck – Extreme rotation / flexion may cause ↑ ICP, • quadriparesis, tongue swelling • Head pins – Adequate plane of anaesthesia • Local infiltration / bolus opioid (fentanyl)

  26. Optimization of ICP • Dural opening in presence of high ICP – • - sudden decompression & transcalvarialherniation • - herniated tissue cannot be interposed back • - permanent neural damage • ICP to be brought within normal limits before opening the dura. • Methods – head elevation, mannitol, furosemide, CSF drainage

  27. Optimize ICP (cont…) Mannitol (20%) Hyperosmolar agent Dose : 0.5 – 2 mg/kg i.v. (0.5-1 mg/kg over 15 min just before opening dura) Action reaches peak at 20-30 min. • Advantages: Draws water from brain (↓ brain bulk) ↓ Hct (↑CBF , O2 delivery) • Disadvantages:1.If given fast, it transiently ↑ blood vol. & may cause CHF , pulmonary edema 2. Hypokalemia 3. Worsen C. edema if BBB disrupted

  28. Optimize ICP (cont…) Furosemide Loop diuretic (Na K 2Cl channel blocker) Dose : 0.5 – 1 mg/kg i.v. • use: sole agent to ↓ ICP adjunct to mannitol Mannitol draws fluid out of brain & lasix discards it through kidneys

  29. Optimize ICP (cont…) CSF drainage • Lumbar subarachnoid drainage system • Ventriculostomy drain (EVD) (connected by tubing to a CSF collection device which can be elevated or lowered) • CSF drainage (↑ICP, aneurysm / ENT surgeries) • ICP measurement CSF drainage • Slow • bolus ≤ 20-30 ml Complications • hematoma formation • infection • if abrupt ↓ICP – aneurysmal rupture

  30. GOAL- Maintain cerebral homeostasis + Aid “slack” brain. TARGET – Anaesthetic agent , Fluid therapy, Neuroprotection strategies. Maintenance

  31. Maintenance (cont…) FLUID THERAPY Principle – BBB is selectively permeable Water crosses freely, most ions (Na+) don't. If BBB disrupted (ischemia, head injury, tumors) – hyperosmolar agents may ↑brain water instead of drawing water out.

  32. Maintenance (cont…) • RECOMMENDATIONS (FLUID RESTRICTION) • FLUID LOSS – Do not replace fasting / III space losses • BLOOD LOSS – Assessment difficult (drapes + continuous irrigation) • SERUM OSMOLARITY – • Maintain at 305- 320 mosm/L • Give NS (309 mosm/L) • Avoid RL (272 mosm/L) • Use them alternately • Avoid glucose containing solutions (5%D , DNS) • Mannitol (0.5 – 2 mg/kg) • Furosemide (0.5 - 1mg/kg)

  33. Maintenance (cont…) NEUROPROTECTION PaO2 PaCO2 BP (sympatholysis, antihypertensives) Glucose ( <170 mg/dL ) Temperature ( controlled hypothermia 32-34⁰C) Analgesia Adequate depth of anaesthesia • OTHERS • Seizure prophylaxis/ control • Steroids • Nimodipine (SAH) • Barbiturates • Magnesium (experimental)

  34. Maintenance (cont…) The chemical brain retractor concept • Mild hyperosmolality • Adequate head-up positioning • Lumbar cerebrospinal fluid drainage • Intravenous anesthetic agent (propofol) • Avoidance of brain retractors • Venous drainage: jugular veins free

  35. Most important but often neglected “ A well planned procedure is often rewarded by a fully awake patient who is appropriately responding to verbal commands and neurological examination.” Emergence • Due to pain and shivering, associated with • ↑ catecholamine release • ↑ O2 Consumption ( X 5 times) • AIMS • To maintain intra + extracranial homeostasis • (MAP- CPP- CBF- ICP- CMRO2 - PaO2 - PaCO2- temp) • Avoid intracranial bleed ( coughing, ventilator fight)

  36. Emergence (cont…)

  37. Emergence (cont…) Checklist for early extubation • Good preop GCS (>8) • CVS stability + normothermia + normoxia • Limited brain surgery, no major brain laceration • No extensive post fossa manipulation ( CN 9 – 12) • No major AVM removal

  38. Emergence (cont…) Indication of late extubation • Low GCS • Inadequate airway control • Intraop catastrophe • Brain edema/ deranged cerebral homeostasis (long duration/ extensive/ repeat surgery) 5. Surgery around vital areas

  39. Immediate postoperative concerns Failure to awaken Nonanaesthetic causes – seizures, cerebral edema, intracranial hematoma, pneumocephalus, vsl occlusion, metabolic/ electrolyte disturbance, herniation. Anaesthesia hangover – opioid, volatile anaesthetic, muscle relaxant.

  40. Immediate postoperative concerns (cont….) 2. Post operative care a) Head end elevation (15-30⁰) b) Adequate ventilation & oxygenation c) Monitoring of neurological function d) Check for serum electrolytes and osmolarity (mannitol, frusemide to continue) e) Seizure prophylaxis (phenytoin / fosphenytoin) f) Seizure treatment (thiopentone 50-100 mg, midazolam 2-4 mg , lorazepam 2 mg)

  41. Immediate postoperative concerns (cont….) g) SIADH • Hyponatremia, S. hyposmolarity, high U. osmolarity • T/T restrict free water intake h) DI • After pituitary surgery • Hyponatremia, S. hyposmolarity, low U. osmolarity • T/T ↑ water intake, vasopressin , desmopressin i) Tension pneumocephalus • Skull X ray / CT • T/T opening the dura

  42. Concerns for posterior fossa surgery • Presentation • Cranial nerve palsies (IX, X) may impair gag reflex- aspiration • Hydrocephalus • Cerebellar dysfunction • Edema in floor of fourth ventricle- damage to resp. centers 2. Cardiovascular instability • Bradycardia and hypertension – due to V nerve stimulation (resolve with cessation of stimulus) • Bradycardia, asystole/ hypotension- due to IX/X nerve stimulation

  43. Concerns for posterior fossa surgery 3. Sitting position Advantages • Better surgical exposure • Improved venous/CSF drainage • Low bleeding • Improved access to airway, chest Disadvantages • VAE • CVS instability

  44. Concerns for pituitary surgery • Trans-sphenoidal resection through nasal/ labial incision • Endocrine manifestations- normo/hypo/ hyperpituitarism • ICP is not a concern due to small size of tumor • Uncontrolled bleeding is rare • Throat pack to prevent blood from accumulating in stomach / aspiration • Nasal breathing obscured by postoperative nasal packs.

  45. References • Miller’s anaesthesia.Ronald D Miller. 7th ed. • Stoelting's Anesthesia and Co-Existing Disease, 5th ed. • Handbook of neuroanaesthesia. James E Cottrell. 4th ed. • Clinical anaesthesia procedures of massachusettes general hospital. 7th ed. • Morgan’s clinical anaesthesiology.4th ed.

  46. THANK YOU

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