NROS SSU Flashcards
methods to reduce secondary injury in ICH and TBI with rationale
SS_NS 1.9
changes in cbf control and CPP in pts with intracranial pathology
SS_NS 1.4
indications for clot retrieval. benefits over traditional treatments. radiological feature confirm diagnosis and demo success of procedure
SS_NS 1.7
mechanisms of impaired sodium homeostasis after neurosurgery. how are they assessed and managed
SS_NS 1.12
risks associated with postioning for neurosurg proecuedres and how do you mitigate them
SS_NS 1.23
anaesthetics plan for elective crani for intracranial tumour
SS_NS 1.26
anaes principles for aneurysm clipping following acute SAH and managment of aaes for critical times during hte case, rationale
preop assessment of pt for elective aneurysm cliipng and plan for anaes. management during temporary and permanent clip application
SS_NS 1.26
Preoperative Assessment for Elective Aneurysm Clipping
Aims:
Identify and optimise comorbidities Assess neurological status and aneurysm-related complications Stratify perioperative risk and plan for intraoperative events
Key Components:
History:
Detailed neurological history: prior SAH, focal deficits, seizures, headaches
Cardiovascular risk factors: hypertension, IHD, arrhythmias
Respiratory, renal, endocrine comorbidities
Medication review: anticoagulants, antiplatelets, nimodipine, antiepileptics
Allergies, previous anaesthetic issues
Examination:
Neurological: GCS, focal deficits, cranial nerves, pupillary response
Cardiovascular: BP, arrhythmias, heart failure signs
Airway assessment (anticipate difficult airway if raised ICP or limited neck mobility)
Investigations:
FBC, U&E, coagulation profile, blood group and crossmatch (minimum 2 units)
ECG, CXR if indicated
Recent imaging: CT/MRI brain, angiogram for aneurysm anatomy
Echocardiogram if cardiac dysfunction suspected
Optimisation:
Control hypertension and other comorbidities
Correct coagulopathy and anaemia
Continue nimodipine for vasospasm prophylaxis
Anticonvulsant prophylaxis if indicated
Discuss perioperative plan with neurosurgical team, including anticipated need for temporary clipping or flow arrest
Clipping Goals:
Maintain cerebral perfusion pressure (CPP) Avoid aneurysm rupture (limit BP surges) Minimise cerebral ischaemia during temporary clipping Provide optimal surgical conditions
anaes plan for awake pt for intracerebral arterial coling following SAH
SS_NS 1.26
Key Principles
Maintain cerebral perfusion pressure (CPP) Prevent aneurysm rebleeding (avoid hypertension/surges) Facilitate patient immobility and cooperation Prepare for remote location challenges (angiography suite) Early detection and management of complications (rebleed, vasospasm)
anaesthesia for acute clot retrieval in pt who has had an embolic stroke
SS_NS 1.26
key anaes issues in spinal surgery, differnet spinal levels and diff anatmoical appraoches
SS_NS 1.26
Special Considerations
Spinal Cord Injury (SCI):
High cervical SCI: Risk of respiratory failure, neurogenic shock, autonomic dysreflexia (T6 and above)
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Avoid suxamethonium after 48–72 hours post-injury (risk of hyperkalaemia)
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Profound haemodynamic instability possible; vasopressor support often required
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Autonomic Dysreflexia:
Occurs in SCI above T6, can be triggered intraoperatively by pain, bladder/bowel distension
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Presents as severe hypertension, bradycardia, arrhythmias; requires prompt recognition and management
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Prone Positioning:
Secure airway before turning, check tube position after turning
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Eyes must be protected, head neutral, abdomen free to reduce venous congestion
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Arms positioned to avoid brachial plexus injury
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Blood Conservation:
Anticipate and prepare for major blood loss: cell salvage, antifibrinolytics (TXA), crossmatch .
Neurophysiological Monitoring:
May require TIVA (total intravenous anaesthesia) to avoid interference with SSEPs/MEPs
anaesthesia for elective IR procedure for AVM
SS_NS 1.26
Complications to Anticipate
Haemorrhage: From AVM rupture or vessel injury. Ischaemic stroke: From inadvertent embolization of normal vessels. Seizure: Due to embolic or ischaemic insult. Cerebral oedema: Sudden occlusion of AVM may cause hyperperfusion of surrounding tissue. Pulmonary embolism: From systemic shunting of embolic material
anaesthetic princpkes for pt requrinig procedures for spinal fluid shunts
SS_NS 1.26
Special Considerations
Raised ICP:
If present, avoid hypoxia, hypercapnia, and hypotension.
Consider mannitol or hypertonic saline if acutely raised ICP is suspected intraoperatively.
Avoid head-down positioning.
Paediatric Patients:
More sensitive to fluid shifts and hypothermia.
Airway management may be challenging, especially in syndromic children or those with previous surgery
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Infection Risk:
Strict aseptic technique is essential. Prophylactic antibiotics as per protocol.
anaesthetic plan for pt reqring intracranial pressure monitoing device
SS_NS 1.26
EVD = Raised ICP
Key Points
Prevent secondary brain injury: avoid hypoxia, hypotension, hypercarbia, hyperglycaemia, hyperthermia
Maintain CPP >60 mmHg, ICP <20-22 mmHg
TIVA preferred, avoid N2O and epileptogenic drugs
Normovolaemia, normocapnia, normothermia
Continue antiepileptics, avoid abrupt withdrawal
Prepare for rapid intervention if ICP rises during device placement
Intracranial Pressure (ICP) Monitoring Devices
Common Types
Intraventricular Catheter (External Ventricular Drain, EVD)
Gold standard; inserted into lateral ventricle.
Allows direct measurement and therapeutic CSF drainage.
Intraparenchymal Microtransducer
Fiberoptic or strain gauge tip inserted into brain parenchyma (usually frontal lobe).
Examples: Camino, Codman.
Measures ICP directly, but cannot drain CSF.
Subdural/Epidural Sensors
Placed in subdural or epidural space.
Less accurate, rarely used.
Subarachnoid Bolt
Inserted into subarachnoid space.
Less common; can become blocked.
anaesthetic management goals in clot retrieval procedures
SS_NS 1.26
Summary:
Endovascular clot retrieval (ECR) is a time-critical, high-stakes procedure for acute ischaemic stroke due to large vessel occlusion. Anaesthetic management must prioritise rapid workflow, haemodynamic stability, neuroprotection, and minimisation of secondary brain injury.
anaesthetic plan and considerationsfor resection of accoustic neuroma
SS_NS 1.27
Summary:
Acoustic neuroma resection is a complex neurosurgical procedure, usually performed via a posterior fossa approach. Anaesthetic management requires meticulous planning to optimize neurological outcome, maintain haemodynamic stability, and prevent complications related to cranial nerve injury, positioning, and intraoperative monitoring.
Other Key Intraoperative Issues
Other Key Intraoperative Issues
Venous Air Embolism (VAE): High risk in sitting position; monitor with precordial Doppler, end-tidal CO₂, and maintain high FiO₂
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Blood Loss: May be significant due to proximity to venous sinuses—cell salvage if available.
Cranial Nerve Monitoring: Avoid long-acting muscle relaxants if facial nerve monitoring required.
Fluid Management: Maintain euvolaemia; avoid hypo-osmolar fluids.
ICP Management: Head elevation, mannitol/hypertonic saline if required, avoid hypercapnia
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anaestheitic consideration for pt underogoing transphenoid hypophysectomy
SS_NS 1.27
neurosurgical techniques for management of trigeminal neuralgia and anaesthetic considerations for those
SS_NS 1.27
Special Anaesthetic Risks
Trigeminal Cardiac Reflex: Manipulation of trigeminal nerve or ganglion can cause profound bradycardia or asystole—have anticholinergics and resuscitation equipment ready
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Airway: Deep sedation may risk airway obstruction—ensure airway is secured or patient is easily arousable
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Positioning: Prevent pressure injuries and maintain neutral alignment, especially in elderly or comorbid patients
anaesthetic considration for awake crani .scalp nerve needed to be block and apporaches
SS_NS 1.27
Key Points:
Awake craniotomy is performed for lesions near eloquent cortex (motor, speech areas) to enable intraoperative neurological assessment. Anaesthetic management must balance patient comfort, immobility, airway safety, and rapid transitions between sedation and wakefulness.
General Anaesthetic Considerations
Patient Selection: Exclude patients unable to cooperate, with severe anxiety, confusion, or inability to lie still
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Preoperative Preparation: Detailed explanation, psychological support, and routine use of anticonvulsants. Avoid sedative premedication
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Monitoring: Standard monitoring plus arterial line, temperature, and urinary catheter if prolonged
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Airway Management: Plan for airway access at all times; draping should allow access. LMA may be used during asleep phases
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Phases of Anaesthesia:
Asleep–Awake–Asleep: General anaesthesia for opening/closure, awake for mapping. Conscious Sedation: Sedation titrated to maintain spontaneous ventilation and cooperation .
Sedation Agents: Propofol, remifentanil, dexmedetomidine—titrate to effect, avoid respiratory depression and hypercapnia
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Analgesia: Scalp nerve block is critical for pain control and to minimize systemic opioid use
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Antiemetics: Routine use to prevent vomiting during awake phase
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Seizure Management: Be prepared for intraoperative seizures, especially during cortical mapping
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Seizures:
Levetiracetam 50mg/kg = 3.5-5g
Phenytoin 20mg/kg = 1.4g-2g
Midazolam 5mg bolus
anaesthetic issues - patient with non-neurosurgical trauma who has a concurrent acute TBI
SS_NS 1.27
Key Principles
Prevent secondary brain injury: avoid hypoxia, hypotension, hypercapnia, hyper/hypoglycaemia, hyperthermia, coagulopathy, and raised intracranial pressure (ICP)
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Trauma management follows ATLS/EMST principles with additional neuroprotection
neurosurgical procedures associate wtih venous air emobolism. discuss detecting and maagnemetn of VAE
SS_NS 1.28
Neurosurgical Procedures Associated with Venous Air Embolism (VAE)
Highest risk: Posterior fossa surgery in the sitting position (incidence up to 45%) due to operative site above the level of the heart and non-collapsible venous sinuses
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Other at-risk procedures: Any neurosurgical operation where venous sinuses or non-collapsible veins are exposed above the right atrium, including some spinal and cranial procedures, especially with hypovolemia or negative venous pressure
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Detection of Venous Air Embolism
Clinical Signs:
Sudden decrease in end-tidal CO₂ (ETCO₂) Hypoxia, hypotension, tachyarrhythmias, or cardiac arrest "Mill wheel" murmur (late sign, low sensitivity) Increased central venous pressure (CVP), pulmonary artery pressure (PAP) Bronchoconstriction, pulmonary oedema (large VAE)
Key points:
VAE is a potentially fatal complication, especially in sitting neurosurgical procedures. Early detection and prompt, coordinated management are critical to prevent morbidity and mortality.
management of acute life threatening intraoperative haemorrhage during neurosurgical procedures, such as aneurysm rupture in coiling or clipping.
SS_NS 1.28
Key Principles:
Immediate recognition and communication. Multidisciplinary, protocol-driven response. Simultaneous resuscitation, neuroprotection, and haemostasis.
Temporising Measures
Induce Hypotension: Controlled hypotension (MAP 50–60 mmHg) may reduce bleeding and facilitate surgical control, but balance with cerebral perfusion needs
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Adenosine-Induced Asystole:
Indication: Brief, profound hypotension/asystole to allow clip placement during uncontrolled rupture. Dose: 0.2–0.4 mg/kg IV bolus (typical adult: 12–24 mg), titrate to effect; aim for 10–30 seconds asystole
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Repeat dosing: Allow full recovery between doses; total dose per case can be high, but monitor for prolonged asystole
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Thiopentone for Neuroprotection:
Indication: Burst suppression prior to prolonged temporary clipping/rupture. Dose: 5–10 mg/kg IV bolus (commonly 200–500 mg in adults)
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Infusion: Titrate to EEG burst suppression if ongoing neuroprotection required.
Cautions: Hypotension, delayed emergence
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Temporary Clipping: If possible, apply proximal vascular control.
management of acute life threatening intraoperative haemorrhage due to aneurysm rupture, compare and contrast management in coiling vs clipping.
SS_NS 1.28
Temporising and Drug-Specific Interventions
Adenosine (Clipping only):
0.2–0.4 mg/kg IV bolus for 10–30 seconds of asystole to facilitate clip placement
.
Thiopentone (Both):
5–10 mg/kg IV bolus for burst suppression and neuroprotection .
Permissive Hypotension (Both):
MAP 50–60 mmHg (short-term) to reduce bleeding and allow surgical/interventional control .
Protamine (Coiling):
1 mg per 100 units heparin to reverse anticoagulation if bleeding is uncontrolled .
Tranexamic Acid (Both, if ongoing bleeding):
1 g IV, if not contraindicated, especially if bleeding is massive and ongoing
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Key Differences: Coiling vs Clipping
SS_NS 1.28
