Presentation on theme: "Anaesthesia for intracranial SOL, including vascular surgeries"— Presentation transcript:
1Anaesthesia for intracranial SOL, including vascular surgeries Dr. Megha AggarwalUniversity College of Medical Sciences & GTB Hospital, Delhi
2Outline Introduction to SOL Neuroanaesthetic goals ClassificationPresentationManagement strategiesNeuroanaesthetic goalsHemodynamic concernsConduct of anaesthesiaPre anaesthetic assessmentMonitoringInduction, maintenance and emergencePost-operative concerns
5Common SOLs1. 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
10Goals of anaesthesiaPreserve both injured & uninjured cerebral territories by global maintenance of cerebral homeostasis.Maintain normocarbia, normotension, normoxia, euthermia, euglycemia.Avoid secondary brain insultsOptimizing operative conditions to facilitate resection
11Anaesthetic implications Depending on type (vascularity) and location (supra/ infratentorial) of tumorSupratentorialICP managementMonitoring brain functionMassive intraoperative hemorrhageSeizuresAir embolism (if venous sinuses traversed)InfratentorialAir embolismCare during vital structure handlingPositioningHigher mortality
13WHY CONTROL BP ? AVM/ aneurysm/ head injuries/ tumors Disruption of cerebral autoregulationBP fluctuation poorly tolerated↑BP – Vasogenic edema, ↑ tumor / aneurysm size, aneurysmal rupture↓ BP – Ischemia/ infarction
14Stimuli for BP fluctuation Preventive measures LaryngoscopyIntubationPositioningSuctionSkeletal fixation of headPreventive measuresDeep plane of anesthesiaAdditional dose of iv anesthetic agentAdequate muscle relaxationLignocaine (1.5 mg/kg)Esmolol (0.5 – 1 mg/kg)
20Preoperative assessment INVESTIGATION7. CT/ MRI – tumor assessmentLocation – silent/ eloquent areaSize – degree of compromise of intracranial dynamics including auto regulation.Ventricular distortion / CSF obstructionMidline shiftPerilesional edema - makes tumor functionally biggerContrast enhancement - degree of BBB disruptionProximity to venous sinuses - blood loss
21ASA physical status ???? Nature of surgery High incidence of systemic involvement – CN palsies, motor/ sensory involvementHigher comorbiditiesPoor surgical outcome
22Premedication1. Sedation -Risk assessment, individualised - often avoided 2. Others - Continue anticonvulsants, antihypertensives, steroids till morning of surgery - mannitol, furosemideSedation - hypoventilation (hypercapnia, hypoxia, airway obst )Sedation - ↓stress→↓ICP→↓ vasogenic edema
23Vascular access1. Intravascular a) 2 large bore i.v cannulas b) CVP -VAE (diagnostic + therapeutic ) - vasoactive drugs 2. Arterial canulation a) NIBP (anticipated blood loss) b) ABG c) Hypotensive anaesthesia
24Monitoring ECG, HR – myocardial ischemia, arrhythmias SpO2 ETCO2 NIBP/ IBP – at level of operative fieldNMT – on non hemiplegic limbTemperatureCVPUrine outputPrecordial doppler, TEE, ETN2ICP – currently rarely used, except in neurotraumatologyUMN lesion↑ Ach receptor densityResistance to NDMR
26PositioningGOAL- Slow and gentle positioning with ⁰ head up tilt to aid cerebral venous drainageVerify cautiously – 1. All potential pressure points padded2. Eyes protected & padded3. Peripheral pulses palpable4. Nerve compression absent5. Ventilation adequate ( PEEP, ETT position)ETT – Kinking in post. OropharynxAdvancement / extubationNeck – Extreme rotation / flexion may cause ↑ ICP,quadriparesis, tongue swellingHead pins – Adequate plane of anaesthesiaLocal infiltration / bolus opioid (fentanyl)
27Optimization of ICP Dural opening in presence of high ICP – - sudden decompression & transcalvarial herniation- herniated tissue cannot be interposed back- permanent neural damageICP to be brought within normal limits before opening the dura.Methods – head elevation, mannitol, furosemide, CSF drainage
28Optimize 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 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 edema2. Hypokalemia3. Worsen C. edema if BBB disrupted
29Optimize ICP (cont…) Furosemide Loop diuretic (Na K 2Cl channel blocker)Dose : 0.5 – 1 mg/kg i.v.use : sole agent to ↓ ICPadjunct to mannitolMannitol draws fluid out of brain & lasix discards it through kidneys
30Optimize 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 measurementCSF drainageSlowbolus ≤ mlComplicationshematoma formationinfectionif abrupt ↓ICP – aneurysmal rupture
31Maintenance ANAESTHETIC AGENT VOLATILE ANAESTHETIC I.V. ANAESTHETIC GOAL- Maintain cerebral homeostasis + Aid “slack” brain.TARGET – Anaesthetic agent , Fluid therapy, Neuroprotection strategies.ANAESTHETIC AGENTVOLATILE ANAESTHETICI.V. ANAESTHETICPROSEasy,Extensively availableIntact CBF – CMRO2 coupling↓brain bulkPropofol blunts N2O cerebrostimulationCONSCBF – CMRO2 uncoupling↑ICP1. Short actingRECOMMENDATIONUse in short, uncomplicated surgeriesAt < 1.5 MACAvoid combination with N2O1. Use in cases with high risk of ↑ICP/ brain bulk
32Maintenance (cont…) FLUID THERAPY Principle – BBB is selectively permeableWater crosses freely, most ions (Na+) don't.If BBB disrupted (ischemia, head injury, tumors) – hyperosmolar agents may ↑brain water instead of drawing water out.
33Maintenance (cont…) RECOMMENDATIONS (FLUID RESTRICTION) FLUID LOSS – Do not replace fasting / III space lossesBLOOD LOSS – Assessment difficult (drapes + continuous irrigation)SERUM OSMOLARITY –Maintain at mosm/LGive NS (309 mosm/L)Avoid RL (272 mosm/L)Use them alternatelyAvoid glucose containing solutions (5%D , DNS)Mannitol (0.5 – 2 mg/kg)Furosemide ( mg/kg)
35Maintenance (cont…) The chemical brain retractor concept Mild hyperosmolalityAdequate head-up positioningLumbar cerebrospinal fluid drainageIntravenous anesthetic agent (propofol)Avoidance of brain retractorsVenous drainage: jugular veins free
36Emergence Due to pain and shivering, associated with 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.”Due to pain and shivering, associated with↑ catecholamine release↑ O2 Consumption ( X 5 times)AIMSTo maintain intra + extracranial homeostasis(MAP- CPP- CBF- ICP- CMRO2 - PaO2 - PaCO2- temp)Avoid intracranial bleed ( coughing, ventilator fight)
37Emergence (cont…) EARLY AWAKENING LATE AWAKENING Early neurological examination & reinterventionLess ↑BP/ catecholamine burst↓ cost of postop careLess risk of ↓O2,↑CO2 associated with anaesthesia hangoverBetter respiratory & hemodynamic controlRECOMMENDATION – Early awakening is recommended unless contraindicated.
38Emergence (cont…) Checklist for early extubation Good preop GCS (>8)CVS stability + normothermia + normoxiaLimited brain surgery, no major brain lacerationNo extensive post fossa manipulation ( CN 9 – 12)No major AVM removal
39Emergence (cont…) Indication of late extubation Low GCS Inadequate airway controlIntraop catastropheBrain edema/ deranged cerebral homeostasis(long duration/ extensive/ repeat surgery)5. Surgery around vital areas
41Immediate postoperative concerns (cont….) 2. Post operative carea) Head end elevation (15-30⁰)b) Adequate ventilation & oxygenationc) Monitoring of neurological functiond) Check for serum electrolytes and osmolarity (mannitol, frusemide to continue)e) Seizure prophylaxis (phenytoin / fosphenytoin)f) Seizure treatment (thiopentone mg, midazolam 2-4 mg , lorazepam 2 mg)
42Immediate postoperative concerns (cont….) g) SIADHHyponatremia, S. hyposmolarity, high U. osmolarityT/T restrict free water intakeh) DIAfter pituitary surgeryHyponatremia, S. hyposmolarity, low U. osmolarityT/T ↑ water intake, vasopressin , desmopressini) Tension pneumocephalusSkull X ray / CTT/T opening the dura
43Concerns for posterior fossa surgery PresentationCranial nerve palsies (IX, X) may impair gag reflex- aspirationHydrocephalusCerebellar dysfunctionEdema in floor of fourth ventricle- damage to resp. centers2. Cardiovascular instabilityBradycardia and hypertension – due to V nerve stimulation (resolve with cessation of stimulus)Bradycardia, asystole/ hypotension- due to IX/X nerve stimulation
44Concerns for posterior fossa surgery 3. Sitting positionAdvantagesBetter surgical exposureImproved venous/CSF drainageLow bleedingImproved access to airway, chestDisadvantagesVAECVS instability
45Concerns for pituitary surgery Trans-sphenoidal resection through nasal/ labial incisionEndocrine manifestations- normo/hypo/ hyperpituitarismICP is not a concern due to small size of tumorUncontrolled bleeding is rareThroat pack to prevent blood from accumulating in stomach / aspirationNasal breathing obscured by postoperative nasal packs.
46References 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.