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1. BONE CEMENT IMPLANTATION SYNDROME (BCIS)

Definition

Pathophysiology - Mechanisms (Know all four)

• Intramedullary pressure can peak at 680 mmHg during cemented arthroplasty
• TEE has documented bone marrow emboli passing through the right heart and pulmonary vasculature intraoperatively

Clinical Features

• Hypoxia (increased pulmonary shunt)
• Hypotension (decreased SVR, decreased cardiac output)
• Pulmonary hypertension (increased PVR)
• Bronchoconstriction
• Cardiac arrhythmias - heart block, sinus arrest
• Right ventricular failure
• Cardiac arrest (in severe cases)

Grading of BCIS (Donaldson Criteria)

Risk Factors

• Metastatic disease to bone
• Previously uninstrumented femoral canal (smooth instrumented canal offers less permeable surface)
• Long-stem prosthesis
• THA for pathologic fractures
• Pre-existing pulmonary hypertension / RV failure
• Large quantity of cement used
• Older, osteoporotic patients

Anaesthetic Considerations

Pre-operative

• Identify high-risk patients (above risk factors)
• Optimize pre-existing cardiac/pulmonary disease
• Consider uncemented prosthesis in high-risk patients

Intra-operative Monitoring

• Arterial line (mandatory in high-risk) - for rapid detection of hemodynamic changes
• CVP - in medically fragile patients
• PA catheter - in very high-risk if cementation unavoidable
• TEE - gold standard for detecting emboli in real time

Prevention (Surgical measures to communicate to surgeon)

• Vigorous pulsatile lavage of medullary canal before cementing
• Distal venting holes drilled in long bones before prosthesis insertion (reduces intramedullary pressure but may cause cement extravasation)
• Thorough canal drying
• Use of uncemented prosthesis in high-risk patients

Anaesthetic Management at Time of Cementing

• Pre-oxygenate - increase FiO2 to 1.0 before cementing
• Maintain euvolemia
• Have vasopressors/inotropes ready
• Communicate with surgeon before cement is inserted

Treatment of BCIS

• Increase FiO2 to 1.0
• IV fluid resuscitation
• Vasopressors - epinephrine is preferred (addresses both RV afterload and inotropy)
• Inotropic support for RV failure
• Mechanical ventilatory support
• CPR if cardiac arrest

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2. KYPHOSCOLIOTIC CORRECTIVE SURGERY - ANAESTHETIC CONSIDERATIONS

Preoperative Assessment

Respiratory (most important system)

• Scoliosis causes restrictive lung disease: decreased TLC, VC, FRC, FEV1
• Cobb angle >65° predicts significant respiratory compromise
• Cobb angle >100° - severe restriction, possible ventilatory failure
• V/Q mismatch due to distorted anatomy
• Hypoxia, hypercapnia in advanced cases
• Screen for pulmonary hypertension (a major risk factor)
• ABG - PaCO2 >45 mmHg is a red flag
• PFTs - VC <40% predicted indicates high perioperative risk
• 6-minute walk test, exercise tolerance

Cardiovascular

• Cor pulmonale secondary to pulmonary hypertension
• Reduced cardiac reserve
• ECG, echocardiography if pulmonary hypertension suspected

Neurological

• Baseline neurological assessment is mandatory (for comparison intraoperatively and postoperatively)
• Document any pre-existing deficits

Difficult Airway

• Cervical spine involvement may cause limited neck mobility
• Assess for difficult intubation - LEMON criteria

Intraoperative Considerations

Positioning

• Prone position is standard for posterior corrective surgery
• Prone position risks: pressure injuries, venous air embolism, brachial plexus injury, ischemic optic neuropathy (ION)
• Use padded bolsters/Wilson frame; ensure abdomen is free (reduces epidural venous engorgement and blood loss)
• Eyes must be free of pressure (corneal abrasion, ION risk)

Airway

• Reinforced/armored ETT preferred in prone position
• Secure ETT meticulously before turning

Spinal Cord Monitoring (see section 4)

• SSEP + MEP monitoring is standard of care
• Plan for wake-up test as backup

Blood Loss Management

• Major blood loss is expected
• Cell salvage intraoperatively
• Tranexamic acid (antifibrinolytic) - evidence supports use in spinal surgery
• Deliberate hypotension (MAP 60-70 mmHg) to reduce blood loss - but must balance against spinal cord perfusion pressure
• Do not allow MAP to fall below 60-65 mmHg - risk of anterior spinal artery ischemia

Anaesthetic Agents - Choice for Neuromonitoring

• TIVA (propofol + remifentanil) is preferred when MEP monitoring is required - avoids volatile agent suppression of MEPs
• If volatiles used, keep <0.5 MAC (less MEP suppression at low concentrations)
• Avoid NMBAs once monitoring begins (MEPs require intact neuromuscular junction)
• Ketamine can enhance MEPs - useful adjunct
• Nitrous oxide should be avoided or used at low concentrations - suppresses MEPs

Fluid Management

• Goal-directed fluid therapy
• Maintain MAP adequate for spinal cord perfusion
• Colloids/blood products as needed

Temperature

• Maintain normothermia - hypothermia suppresses SSEPs and MEPs

Postoperative Considerations

• ICU/HDU admission for severe cases (pre-existing respiratory compromise)
• Pulmonary function may worsen acutely post-op due to pain and splinting
• Aggressive chest physiotherapy
• Neurological examination at earliest opportunity
• Pain management: opioid + NSAID + regional technique where possible

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3. LOWER LIMB LONG BONE FRACTURE - ANAESTHETIC CONSIDERATIONS

Initial Assessment (ABCDE)

• Hemorrhage: long bone fractures cause significant blood loss
  • Femur fracture: 1-2 L blood loss into thigh compartment
  • Tibia fracture: 0.5-1 L
• Neurovascular status of limb
• Associated injuries (polytrauma)
• Fat embolism syndrome (FES) risk

Fat Embolism Syndrome (FES)

• Incidence with isolated long bone fracture: 0.5-0.9%
• Presents 24-48 hours after injury (fulminant within hours occasionally)
• Gurd's Criteria (need 1 major + 4 minor/lab):

• Schonfeld Fat Embolism Index (point scoring system) - alternative diagnostic tool
• Prevention: early fracture fixation + corticosteroid use may be beneficial
• Management: supportive - early mechanical ventilation, O2, fluid management
• Mortality: 10-20%

Regional vs General Anaesthesia

Regional Anaesthesia (preferred where feasible)

• Spinal anaesthesia - suitable for tibia/femur surgery
• Femoral nerve block / Fascia iliaca block - excellent for femur fractures; reduces opioid requirement, reduces blood loss
• Sciatic + femoral nerve block - for below-knee procedures
• Advantages: avoids airway manipulation, reduced blood loss, reduced DVT/PE risk, preserved respiratory function, faster recovery
• Disadvantages: may mask compartment syndrome (controversial), not suitable in coagulopathy

General Anaesthesia

• RSI if full stomach (trauma patient - always assume full stomach)
• LMA vs ETT based on duration and nature of procedure

Tourniquet Considerations

• Inflation pressure: systolic BP + 100 mmHg (upper limb 50-75 mmHg above)
• Duration limit: <2 hours (prolonged inflation → muscle ischemia, rhabdomyolysis, perioperative neuropathy)
• Tourniquet inflation causes rapid central blood volume shift
• Tourniquet pain: a specific phenomenon - occurs even under adequate regional block after 20-30 min; may require IV supplementation or GA conversion
• Tourniquet deflation (release): sudden hypotension, acidosis, hypercapnia (from metabolite washout), and potential embolism - anticipate and treat

Blood Loss and Resuscitation

• Crossmatch; IV access ×2 large bore
• Tranexamic acid - reduces blood loss in long bone surgery and trauma
• Early fixation reduces blood loss and FES risk
• GDT for fluids

Positioning

• Supine most commonly; traction table for femur fractures
• Risk of perineal post injury with traction table (pudendal nerve compression)

DVT Prophylaxis

• Without prophylaxis, DVT develops in 40-80% of orthopaedic patients
• 1-10% clinical PE; fatal PE in 0.2-5%
• Mechanical (TED stockings, IPC) + pharmacological (LMWH, factor Xa inhibitors)
• Recent data: <1% DVT/PE with appropriate prophylaxis in arthroplasty

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4. THE WAKE-UP TEST

Definition

Indications

• Scoliosis/kyphoscoliosis corrective surgery (primary indication)
• Any spine surgery with risk of spinal cord compromise
• When SSEP/MEP monitoring is unavailable, equivocal, or fails
• Patients where neurophysiological monitoring is unreliable (e.g., pre-existing neurological deficits)

Procedure (Step-by-Step)

1. Pre-operative preparation - explain the procedure to the patient the day before surgery; tell them they will be briefly awakened and asked to squeeze hands and move feet; this dramatically reduces anxiety and the chance of recall being distressing
2. At the appropriate surgical moment, the anaesthesiologist reduces/stops anaesthetic agents:
   • Turn off volatile agents or stop propofol infusion
   • Stop or reduce opioid infusion
   • Reversal of NMBAs if used (confirm TOF ratio adequate)
3. Allow the patient to emerge to a light plane where they can follow commands
4. Ask the patient to:
   • Squeeze hands (establishes the patient is awake and cooperative)
   • Move feet / wiggle toes (tests motor integrity of spinal cord)
5. If bilateral foot movement is intact - instrumentation is confirmed safe; re-anaesthetize promptly
6. If foot movement is absent - release one notch of rod distraction → repeat test
7. Re-anaesthetize immediately after confirmation

Anaesthetic Technique for Wake-up Test

• TIVA preferred: short-acting agents - propofol infusion + remifentanil (very rapid offset)
• Volatile agents: isoflurane/sevoflurane can be used but have slower offset
• Avoid long-acting NMBAs intraoperatively if wake-up test planned
• Maintain analgesia with opioids - essential for ETT tolerance during the awake period (remifentanil infusion maintained or low-dose morphine pre-given)
• Midazolam pre-operatively reduces risk of distressing recall

Advantages

• Simple, no specialized equipment needed
• Directly assesses motor function (which SSEPs do not monitor)
• Gold standard confirmation of cord integrity
• Definitive - no false negatives for motor function

Disadvantages / Risks

Comparison: Wake-up Test vs IOM

Current Standard of Care

• SSEP + MEP combined monitoring is the accepted standard (American Society of Neurophysiologic Monitoring consensus)
• Wake-up test remains a valuable backup, especially when:
  • IOM is unavailable
  • IOM signals are equivocal or lost
  • Patient has pre-existing deficits making IOM unreliable
• Ankle clonus test is an alternative to the full wake-up test on emergence - absence of clonus is abnormal

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Quick Exam Summary Table

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MD ANAESTHESIA - 50 MARKS EXAM ANSWER

Anaesthetic Considerations in:

(A) Bone Cement Implantation Syndrome (BCIS)

(B) Kyphoscoliotic Corrective Surgery

(C) Lower Limb Long Bone Fracture Surgery

(D) The Wake-Up Test

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PART A: BONE CEMENT IMPLANTATION SYNDROME (BCIS)

Introduction / Definition

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Chemistry of Bone Cement

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Pathophysiology - Four Mechanisms (EXAM FAVOURITE)

Key fact (Miller's 10e): Intraoperative TEE has documented bone marrow debris passing through the right atrium and pulmonary vasculature during cemented arthroplasty. The syndrome extensively overlaps with FES.

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Clinical Features

• Hypoxia - increased pulmonary shunt, V/Q mismatch
• Hypotension - decreased SVR + decreased cardiac output
• Pulmonary hypertension - increased PVR
• Bronchoconstriction
• Cardiac arrhythmias - heart block, sinus arrest
• Right ventricular failure (acute cor pulmonale)
• Cardiac arrest - in severe cases
• Altered mental status (if awake/regional technique)

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Grading of BCIS (Donaldson Classification)

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Risk Factors

• Age >70 years, poor functional reserve
• Pre-existing pulmonary hypertension / RV dysfunction
• Severe cardiovascular disease

• Metastatic disease to bone
• Previously uninstrumented femoral canal (smooth/sclerotic wall after prior instrumentation offers less permeable surface)
• Long-stem prosthesis
• THA for pathological fractures
• Large volume of cement used

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Anaesthetic Considerations

Pre-operative Assessment

• Identify high-risk patients (above factors)
• ECG, echocardiography to assess RV function and pulmonary pressures
• Optimise pre-existing cardiac and pulmonary disease
• Discuss risk-benefit of cemented vs uncemented prosthesis with surgeon
• Use uncemented prosthesis in very high-risk patients (Miller's 10e)

Monitoring

• Intra-arterial line - mandatory in high-risk patients (rapid beat-to-beat BP for early detection)
• Central venous catheter - in medically fragile patients
• PA catheter - in very high-risk if cementation unavoidable
• Transoesophageal echocardiography (TEE) - gold standard; detects emboli in real time before haemodynamic compromise

Intra-operative - Anaesthetic Plan

1. Pre-oxygenation before cementing - increase FiO2 to 1.0 before cement insertion
2. Communicate with surgeon 1-2 minutes before cementing: "Ready for cement"
3. Ensure euvolaemia (neither hypo- nor hypervolaemic)
4. Have vasopressors drawn up and ready
5. Maintain adequate MAP

Surgical Prevention Measures (communicate to surgeon)

• Vigorous pulsatile lavage of medullary canal - removes debris before cementing
• Distal venting hole drilled in femur before prosthesis insertion - reduces intramedullary pressure (but note: may cause cement extravasation)
• Thorough canal drying
• Use of cementless prosthesis in high-risk patients

Treatment of Established BCIS

Key phrase: "Management is mainly supportive - ventilatory support, fluid resuscitation, vasopressor support. Epinephrine with the goal to off-load the right ventricle." (Miller's Anesthesia 10e)

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PART B: KYPHOSCOLIOTIC CORRECTIVE SURGERY

Pathophysiology of Kyphoscoliosis Relevant to Anaesthesia

• Restrictive lung disease: chest wall deformity → reduced TLC, VC, FRC, FEV1
• V/Q mismatch: distorted lung architecture
• Pulmonary hypertension (from chronic hypoxia-induced vasoconstriction)
• Cor pulmonale: right heart strain from pulmonary hypertension
• Reduced respiratory reserve: poor response to any anaesthetic-related respiratory depression

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Pre-operative Assessment

Respiratory (MOST IMPORTANT)

Key point (Fishman's Pulmonary Diseases): Postoperative respiratory complications occur in up to 20% of kyphoscoliosis surgery patients. Risk factors: nonidiopathic scoliosis, anterior open fusion, age >20 years, intellectual disability, preoperative hypoxaemia, obstructive PFTs.

Cardiovascular

• ECG: RVH, right axis deviation, P-pulmonale (cor pulmonale)
• Echocardiography: RV function, pulmonary artery pressures, TR
• 2D Echo mandatory if pulmonary hypertension suspected

Neurological Assessment

• Detailed neurological examination - document any pre-existing deficits (medico-legally mandatory; baseline for intraoperative monitoring)
• MRI spine: assess cord compression, tethering, syrinx

Airway Assessment

• Cervical spine involvement may limit neck mobility
• Full LEMON criteria assessment
• Fibreoptic intubation may be needed if neck immobility

Nutritional / Other

• Malnutrition common (especially neuromuscular scoliosis)
• Coagulation profile
• Crossmatch 4-6 units blood (major surgery, expected blood loss)
• Pre-operative autologous blood donation (if time permits)

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Intra-operative Management

Patient Positioning

• Prone position is standard (posterior corrective surgery)
• Careful padding: bony prominences, eyes, ears, genitalia
• Abdomen must be free (reduces epidural venous engorgement → reduces intraoperative blood loss)
• Eyes free of pressure - ischaemic optic neuropathy (ION) and corneal abrasion risks
• Arms positioned at <90° abduction (brachial plexus injury risk)
• Head neutral position (no neck hyperextension/flexion)

Airway Management

• Reinforced (armoured/spiral-wound) ETT - prevents kinking in prone position
• Secure ETT meticulously with adhesive tape + bandage before turning prone
• Verify ETT position after prone positioning
• Double-lumen tube / selective lung ventilation if anterior approach (thoracotomy)

Anaesthetic Technique - Choice Depends on Neuromonitoring

• Avoid NMBAs once neuromonitoring begins (MEPs require intact NMJ)
• Ketamine as adjunct - enhances MEPs (favourable)
• Dexmedetomidine infusion - reduces opioid requirement, compatible with neuromonitoring
• Avoid nitrous oxide - suppresses MEPs; also risk of pneumothorax (especially if anterior approach)
• BIS monitoring when TIVA used - prevent awareness

Blood Loss Management (CRITICAL)

Ventilation

• Prone ventilation: increased airway pressures expected
• Lung-protective ventilation: Vt 6-8 mL/kg IBW, PEEP 5-8 cmH2O
• Permissive hypercapnia to some extent is acceptable
• Monitor EtCO2 continuously

Fluid Management

• Goal-directed fluid therapy (GDT) using invasive monitoring
• Arterial line (mandatory) + CVP ± cardiac output monitoring

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Post-operative Management

• ICU/HDU admission for patients with:
  • Pre-existing severe respiratory disease (VC <40%)
  • Cor pulmonale
  • Intraoperative complications
• Ventilation may be required postoperatively in severe respiratory compromise
• Chest physiotherapy from day 1
• Neurological assessment at earliest opportunity post-extubation
• Pain management: multimodal - opioid + NSAID + paracetamol; epidural/intrathecal morphine in some centres
• Thromboprophylaxis: LMWH + TED stockings + IPC

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PART C: LOWER LIMB LONG BONE FRACTURE - ANAESTHETIC CONSIDERATIONS

Types and Expected Blood Loss

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Pre-operative Assessment

History

• Mechanism (trauma vs pathological)
• Time of last meal (full stomach - most trauma cases)
• Associated injuries (ATLS survey)
• Comorbidities, medications (anticoagulants)
• Neurovascular status of limb distal to fracture

Investigations

• FBC, coagulation, urea/electrolytes, group & crossmatch
• Blood glucose
• ECG, CXR if indicated
• X-rays of fracture

IV Access

• Two large-bore IV cannulae (14-16G)
• Consider central line in haemodynamically unstable patients

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Fat Embolism Syndrome (FES)

Definition

Incidence

• Isolated long bone fracture: 0.5-0.9%
• Bilateral femur fractures / multiple injuries: up to 5-10%
• Symptoms typically appear 24-48 hours after injury (fulminant within hours occasionally)
• Mortality: 10-20%

Pathophysiology

• Mechanical theory: fat globules enter disrupted venous sinusoids → pulmonary microvascular occlusion
• Biochemical theory: free fatty acids from hydrolysis of fat emboli → direct pulmonary endothelial damage, inflammation

Diagnostic Criteria

Prevention

• Early fracture fixation - most important intervention
• Corticosteroids - controversial but may reduce incidence
• Avoid prolonged immobilization

Management of FES

• Largely supportive
• High-flow O2 (maintain PaO2 >70 mmHg)
• Early mechanical ventilation if respiratory failure
• Lung-protective ventilation (FES causes ARDS-like picture)
• Haemodynamic support
• No specific antidote

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Choice of Anaesthesia: Regional vs General

Regional Anaesthesia (PREFERRED where feasible)

• Avoids airway manipulation (aspiration risk in trauma)
• Reduced intraoperative blood loss (sympatholysis → vasodilatation → reduced venous pressure)
• Reduced DVT/PE incidence
• Better preserved respiratory function post-op
• Lower metabolic stress response

• Coagulopathy (anticoagulant use)
• Patient refusal
• Infection at site
• Haemodynamic instability (relative)

General Anaesthesia

• RSI mandatory in trauma (full stomach - all trauma patients assumed full stomach until proven otherwise)
• Agents: propofol/ketamine + suxamethonium (RSI); maintain with volatile + opioid
• LMA vs ETT: ETT preferred for prolonged surgery, prone position, airway at risk

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Tourniquet Considerations

Physiological Changes with Tourniquet

• Sudden central blood volume increase (exsanguination + inflation)
• Rise in CVP and arterial BP
• Rise in body temperature (especially paediatrics)
• Metabolic: limb ischaemia → lactate accumulation distally

• Sudden hypotension (washout of ischaemic metabolites, histamine)
• Hypercapnia (CO2 washout from ischaemic limb)
• Acidosis (lactic acid washout)
• Potential FES/BCIS if cement used
• Hypothermia (cold ischaemic limb blood returns centrally)

Tourniquet Pain

• Occurs even under adequate regional block after 20-30 min
• Due to C-fibre (unmyelinated) pain transmission bypassing blocked A-delta fibres
• Management: IV opioid supplementation, conversion to GA if intolerable

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DVT Prophylaxis

1. Mechanical: TED stockings, intermittent pneumatic compression (IPC) - start intraoperatively
2. Pharmacological: LMWH (enoxaparin), fondaparinux, rivaroxaban, apixaban
3. Early mobilisation

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Compartment Syndrome

• Must be vigilant in long bone fractures (especially tibia, forearm)
• Regional anaesthesia may mask pain (the earliest symptom) - controversial issue
• Pain out of proportion to injury is the cardinal sign
• Pain on passive stretch of muscles
• If suspected: do not give more analgesics - immediately decompress (fasciotomy)

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PART D: THE WAKE-UP TEST (Stagnara Wake-Up Test)

Definition

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Historical Background

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Indications

• Corrective surgery for scoliosis/kyphoscoliosis (primary indication)
• Any spinal surgery at risk of cord compromise
• When SSEP/MEP monitoring is unavailable or equivocal
• When neurophysiological monitoring signals are lost or unreliable
• Patients with pre-existing neurological deficits (making baseline IONM interpretation difficult)
• Neuromuscular scoliosis patients - note: many cannot cooperate with wake-up test; IOM preferred (Campbell's Operative Orthopaedics 15e)

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Pre-operative Preparation (CRITICAL STEP - Commonly Examined)

• Explain the procedure to the patient clearly
• Tell them: "During the operation, we will briefly wake you up. You will hear us, you will not feel any pain. We will ask you to squeeze our hands and then to move your feet. Please do this and then go back to sleep."
• Demonstrate the commands
• Reassure that recall is uncommon (0-20%), and when it occurs it is rarely distressing
• Address anxiety and fears
• Pre-operative midazolam (oral/IM) - reduces risk of distressing recall

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Anaesthetic Technique Best Suited for Wake-Up Test

Agents of Choice

• TIVA with propofol + remifentanil infusion - IDEAL
  • Very short context-sensitive half-life
  • Rapid offset: propofol ~5-8 min, remifentanil <5 min
  • Patient awakens quickly and predictably
• Alternatives: volatile agent (isoflurane/sevoflurane) + opioid + ± N2O
  • Slower offset than TIVA; less predictable timing

Agents to AVOID

• Long-acting NMBAs (vecuronium, rocuronium if reversal unavailable) - patient must be able to move limbs
• Ketamine as the sole hypnotic - may cause agitation on emergence
• High-dose midazolam intraoperatively - prolonged sedation

Opioid Strategy (Key Exam Point)

• Opioids are essential - they provide analgesia and allow tolerance of ETT while awake
• Remifentanil infusion maintained at low dose during wake-up (analgesic effect continues but consciousness returns)
• Or: give a small dose of morphine (longer-acting) 30 min before planned wake-up so it covers the awake period without sedation

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Step-by-Step Procedure

1. Surgeon signals readiness (after rod insertion and correction)
2. Anaesthesiologist stops propofol infusion (or turns off volatile)
3. Maintains low-dose remifentanil for analgesia/ETT tolerance
4. Confirm adequate NMB reversal (TOF ratio >0.9 at adductor pollicis)
5. Reduce stimulation to minimum
6. Call patient by name; say: "Can you hear me? Squeeze my hand"
7. When patient responds: "Now move your feet/wiggle your toes"
8. Interpretation:
   • Both feet move = spinal cord intact → proceed
   • Hands move but NOT feet = motor deficit; release one notch of rod distraction → repeat test
   • Neither hands nor feet = anaesthesia still too deep OR complete cord injury
9. Immediately re-anaesthetise once motor function confirmed
10. Document time awake, response, any recall on post-op review

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Advantages of Wake-Up Test

• Directly assesses MOTOR function - SSEPs only monitor dorsal columns; wake-up test monitors anterior column motor tracts
• No specialized equipment or neurophysiology team required
• Can be performed anywhere
• Simple, inexpensive
• No false negatives for motor function when properly performed
• Definitive clinical confirmation

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Disadvantages / Risks

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Wake-Up Test vs Intraoperative Neuromonitoring (IONM): Comparison Table

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Current Standard of Care for Spinal Cord Monitoring

• SSEP + MEP combined monitoring is the accepted standard to prevent injury to both sensory and motor tracts during spinal column surgery (Miller's Anesthesia 10e)
• Wake-up test is retained as the definitive backup when:
  • IONM unavailable
  • Signals equivocal or lost
  • IOM signals do not return to baseline after intervention

Response Protocol When IONM Changes Occur (Barash 9e)

1. Halt surgery - stop applying corrective forces
2. Raise MAP to normal or 20% above normal (improve spinal cord perfusion)
3. Reduce or discontinue volatile agents
4. ABG - exclude hypoxaemia/hypercapnia/acidosis (metabolic causes)
5. If signals do not recover → release rod distraction one notch
6. Perform wake-up test to definitively exclude motor deficit

Ankle Clonus Test

• Alternative simpler test on emergence
• Clonus should be present briefly on emergence
• Absence of clonus on emergence = abnormal (Campbell's 15e)

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INTEGRATED SUMMARY TABLE (For Quick Revision)

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