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

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Presentation on theme: "Anaesthesia for intracranial SOL, including vascular surgeries Dr. Megha Aggarwal University College of Medical Sciences & GTB Hospital, Delhi."— Presentation transcript:

1 Anaesthesia for intracranial SOL, including vascular surgeries Dr. Megha Aggarwal 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 CONGENITALDermoid, epidermoid, teratoma. TRAUMATICSubdural & extradural haematoma INFLAMMATORYAbscess, tuberculoma, syphilitic gumma,fungal granulomas. PARASITICCysticercosis, hydratid cyst, amebic abscess, Schistosoma NEOPLASMS Meningionas, gliomas, choroid pappilomas, metastasis VASCULARAneurysms, A-V malformations

4 Neoplasms

5 1. Meningioma- 90% supratentorial 5-6th decade benign Highly vascular with large feeding vessels 2. Gliomas - most common 1 ⁰ intracranial tumors slow growing astrocytomas to malignant glioblastomas seizures, focal deficits, ↑ ICP as per tumour type Common SOLs

6 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 Common SOLs (cont …)

7 ANATOMICAL REGIONCLINICAL SIGNS Supratentorial (forebrain) Seizures Headache Motor/ sensory deficits Infratentorial (brainstem) (RAS, CN, Cardiac & resp centres) - CN deficit (3-12)- ocular palsy, dysphagia, laryngeal dysfunction (chronic aspiration). - Arrhythmias/ respiratory irregularities Sleep abnormality Infratentorial (cerebellum) Ataxia Tremors Vestibular signs Hydrocephalus Infratentorial (vestibular system) Head tilt Postural deficit Nystagmus How do they present ?

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

9 Treatment Chemotherapy Surgical resection Radiotherapy

10 Goals of anaesthesia 1.Preserve both injured & uninjured cerebral territories by global maintenance of cerebral homeostasis. 2.Maintain normocarbia, normotension, normoxia, euthermia, euglycemia. 3.Avoid secondary brain insults 4.Optimizing operative conditions to facilitate resection

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

12 Secondary insults INTRACRANIALSYSTEMIC Increased intracranial pressureHypercapnia/hypoxemia EpilepsyHypo-/hypertension VasospasmHypo-/hyperglycemia Herniation: falx, tentorium, foramen magnum, craniotomy Low cardiac output Midline shift: tearing of cerebral vessels Hypo-osmolality Shivering/pyrexia

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

14 Stimuli for BP fluctuation 1.Laryngoscopy 2.Intubation 3.Positioning 4.Suction 5.Skeletal fixation of head Stimuli for BP fluctuation 1.Laryngoscopy 2.Intubation 3.Positioning 4.Suction 5.Skeletal fixation of head Preventive measures 1.Deep plane of anesthesia 2.Additional dose of iv anesthetic agent 3.Adequate muscle relaxation 4.Lignocaine (1.5 mg/kg) 5.Esmolol (0.5 – 1 mg/kg) Preventive measures 1.Deep plane of anesthesia 2.Additional dose of iv anesthetic agent 3.Adequate muscle relaxation 4.Lignocaine (1.5 mg/kg) 5.Esmolol (0.5 – 1 mg/kg)

15 INVESTIGATIONSEXAMINATION HISTORY Preoperative assessment Assessment & documentation

16 Preoperative assessment 1.Level of consciousness 2.Seizures - ↑ CMRO 2, ↑ ICP 3.↑ ICP – headache, vomiting, without nausea, blurred vision, ocular palsy (CN 6) 4.Hydration – fluid intake, NPO status, diuretics, SIADH 5.Medications – steroids, antiepileptic drugs, aspirin/ clopidogrel, diuretics, mannitol 6.CN palsies- dysphagia, laryngeal dysfunction 7.Associate systemic illness-  Cardiac – HTN (hypotensive anaesthesia)  Respiratory  Renal – intraoperative mannitol and diuretics, SIADH, DI HISTORY

17 Preoperative assessment 1.Mental status, level of consciousness (GCS) 2.Hydration status 3.Systemic examination a) CNS ↑ICP – papilloedema, cushing response (↑BP, ↓HR), sutural diastasis, 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 (3 rd CN) EXAMINATION

18 Preoperative assessment b) Respiratory- effect of positioning, resp. pattern, neurogenic pulm. 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 EXAMINATION

19 Preoperative assessment 1.Complete blood count – Hb, TLC, Platelet count 2.RBS – hyperglycemia – cerebral edema, ↑ischemic brain injury 3.KFT – urea, Na, K 4.Coagulation profile 5.ECG – ischemic changes, arrhythmias 6.CXR INVESTIGATION

20 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 Preoperative assessment INVESTIGATION

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

22 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

23 Vascular access 1. 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

24 Monitoring 1.ECG, HR – myocardial ischemia, arrhythmias 2.SpO 2 3.ETCO 2 4.NIBP/ IBP – at level of operative field 5.NMT – on non hemiplegic limb 6.Temperature 7.CVP 8.Urine output 9.Precordial doppler, TEE, ETN 2 10.ICP – currently rarely used, except in neurotraumatology UMN lesion ↑ Ach receptor density Resistance to NDMR

25 Induction GOALS – Normotension, Normocarbia, Normoxia Preoxygenation P/M – opioid (fentanyl 1-2 μg/kg, morphine 0.1 mg/kg) 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 Lignocaine, Esmolol, 2 nd dose of i.v induction agent sec earlier

26 Positioning GOAL- Slow and gentle positioning with ⁰ 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)

27 Dural opening in presence of high ICP – - sudden decompression & transcalvarial herniation - 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 Optimization of ICP

28 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 edema 2. Hypokalemia 3. Worsen C. edema if BBB disrupted Optimize ICP (cont…)

29 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

30 Optimize ICP (cont…) CSF drainage 1.Lumbar subarachnoid drainage system 2.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 ≤ ml Complications – hematoma formation –infection –if abrupt ↓ICP – aneurysmal rupture

31 Maintenance GOAL- Maintain cerebral homeostasis + Aid “slack” brain. TARGET – Anaesthetic agent, Fluid therapy, Neuroprotection strategies. ANAESTHETIC AGENT VOLATILE ANAESTHETIC I.V. ANAESTHETIC PROS1.Easy, 2.Extensively available 1.Intact CBF – CMRO2 coupling 2.↓brain bulk 3.Propofol blunts N2O cerebrostimulation CONS1.CBF – CMRO2 uncoupling 2.↑ICP 1. Short acting RECOMMENDATION1.Use in short, uncomplicated surgeries 2.At < 1.5 MAC 3.Avoid combination with N2O 1. Use in cases with high risk of ↑ICP/ brain bulk

32 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.

33 RECOMMENDATIONS (FLUID RESTRICTION) 1.FLUID LOSS – Do not replace fasting / III space losses 2.BLOOD LOSS – Assessment difficult (drapes + continuous irrigation) 3.SERUM OSMOLARITY – Maintain at 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 ( mg/kg) Maintenance (cont…)

34 NEUROPROTECTION a)PaO2 b)PaCO2 c)BP (sympatholysis, antihypertensives) d)Glucose ( <170 mg/dL ) e)Temperature ( controlled hypothermia ⁰ C) f)Analgesia g)Adequate depth of anaesthesia Maintenance (cont…) OTHERS a)Seizure prophylaxis/ control b)Steroids c)Nimodipine (SAH) d)Barbiturates e)Magnesium (experimental)

35 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 Maintenance (cont…)

36 Emergence 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) AIMS  To maintain intra + extracranial homeostasis (MAP- CPP- CBF- ICP- CMRO2 - PaO2 - PaCO2- temp)  Avoid intracranial bleed ( coughing, ventilator fight)

37 Emergence (cont…) EARLY AWAKENINGLATE AWAKENING 1.Early neurological examination & reintervention 2.Less ↑BP/ catecholamine burst 3.↓ cost of postop care 1.Less risk of ↓O 2, ↑CO 2 associated with anaesthesia hangover 2.Better respiratory & hemodynamic control RECOMMENDATION – Early awakening is recommended unless contraindicated.

38 Checklist for early extubation 1.Good preop GCS (>8) 2.CVS stability + normothermia + normoxia 3.Limited brain surgery, no major brain laceration 4.No extensive post fossa manipulation ( CN 9 – 12) 5.No major AVM removal Emergence (cont…)

39 Indication of late extubation 1.Low GCS 2.Inadequate airway control 3.Intraop catastrophe 4.Brain edema/ deranged cerebral homeostasis (long duration/ extensive/ repeat surgery) 5. Surgery around vital areas Emergence (cont…)

40 Immediate postoperative concerns 1.Failure to awaken Nonanaesthetic causes – seizures, cerebral edema, intracranial hematoma, pneumocephalus, vsl occlusion, metabolic/ electrolyte disturbance, herniation. Anaesthesia hangover – opioid, volatile anaesthetic, muscle relaxant.

41 Immediate postoperative concerns (cont….) 2. Post operative care a) Head end elevation (15-30 ⁰ ) 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 mg, midazolam 2-4 mg, lorazepam 2 mg)

42 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

43 Concerns for posterior fossa surgery 1.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

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

45 1.Trans-sphenoidal resection through nasal/ labial incision 2.Endocrine manifestations- normo/hypo/ hyperpituitarism 3.ICP is not a concern due to small size of tumor 4.Uncontrolled bleeding is rare 5.Throat pack to prevent blood from accumulating in stomach / aspiration 6.Nasal breathing obscured by postoperative nasal packs. Concerns for pituitary surgery

46 1.Miller’s anaesthesia.Ronald D Miller. 7 th ed. 2.Stoelting's Anesthesia and Co-Existing Disease, 5th ed. 3.Handbook of neuroanaesthesia. James E Cottrell. 4 th ed. 4.Clinical anaesthesia procedures of massachusettes general hospital. 7 th ed. 5.Morgan’s clinical anaesthesiology.4 th ed. References

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