2024.2 Day 2 VIVA 15

Regional Anaesthesia

A 60-year-old male is booked for an elective right total knee replacement in two weeks due to severe osteoarthritis.

He has a history of type 2 diabetes, hypertension, and dyslipidemia, managed with metformin, ramipril, and atorvastatin.

He prefers spinal anaesthesia, as his friend had the same procedure with that option, and he wants to know if it’s suitable for him.

Please describe your pre-anaesthetic assessment for this patient.

• Systemic Comorbidity Review:

  • Diabetes: Ask about glycaemic control and obtain recent HbA1c. Assess for peripheral neuropathy—its presence may increase risk of worsening post-block and is a relative contraindication. Plan perioperative glucose monitoring and insulin sliding scale if necessary. Stop metformin on day of surgery due to risk of lactic acidosis, especially if renal function is impaired.

  • Hypertension: Review chronic BP control and target organ effects (e.g., ECG changes, renal dysfunction). Note ramipril use—ACE inhibitors can worsen spinal-induced hypotension. Withhold on day of surgery if elective.

  • Dyslipidaemia: Confirm ongoing statin use, which reduces cardiovascular risk.

• Spinal Suitability Factors:

  • Absolute contraindications to spinal include infection at the injection site, raised ICP, sepsis, uncorrected coagulopathy (INR >1.4), platelets <80,000, and severe hypovolaemia.

  • Relative contraindications include fixed cardiac output states (e.g., severe aortic stenosis), spinal deformities (e.g., kyphoscoliosis), or pre-existing neuropathy. Carefully weigh risks vs benefits.

• Physical Examination:

  • Cardiovascular: Auscultate for murmurs—especially systolic murmur raising suspicion of aortic stenosis. Evaluate volume status.

  • Neurological: Perform and document thorough neuro exam to detect pre-existing neuropathy (diabetic or other). Important for medico-legal protection.

  • Spine: Palpate for landmarks (L3–L5). Assess for challenges to needle placement such as scoliosis or obesity.

• Investigations:

  • Order FBC, UEC, and HbA1c if not available within last 3 months.

  • ECG indicated given patient’s age and comorbidities (hypertension and diabetes), as per ANZCA PG07.

  • INR if there is any history or suspicion of anticoagulant use or liver dysfunction.

• Anaesthetic Planning and Consent:

  • Discuss benefits of spinal: reduced PONV, lower risk of VTE, decreased blood loss, and reduced need for systemic opioids.

  • Discuss potential complications: hypotension (especially due to ramipril), urinary retention, post-dural puncture headache (PDPH), nerve injury (~1:10,000), and failed block.

His INR today is 1.6. How do you proceed?

• INR >1.4 is a contraindication per ASRA/ANZCA.

• Delay spinal; manage with GA or reverse INR if urgent (e.g., vitamin K or FFP).

• Investigate cause (e.g., unreported anticoagulant use or hepatic dysfunction).

The INR is 1.6. Would you proceed with the spinal, and if not, what alternatives do you consider? How would you communicate this to the patient and the team?

• INR >1.4 is an absolute contraindication per ANZCA and ASRA guidelines.

• I would not proceed with neuraxial anaesthesia in this case. I would check for any underlying cause—undiagnosed liver disease or unreported anticoagulant use.

• Discuss plan with the patient and surgical team. If surgery is urgent, consider correcting INR with vitamin K or FFP. Otherwise, proceed with general anaesthesia and provide adequate regional/multimodal analgesia.

• Document discussion and clinical reasoning clearly in the notes.

Spine exam reveals mild lumbar scoliosis. What are your technical options to proceed with spinal, and what factors would guide your decision to abandon the attempt?

• Anticipate difficulty with landmark identification and needle placement.

• Consider alternative approaches:

  • Paramedian or Taylor’s approach (especially if scoliosis is unilateral or affects midline anatomy)

  • Pre-procedural ultrasound to identify interspaces and midline

• Factors guiding decision to abandon include multiple failed attempts, increasing patient discomfort, time pressure, or signs of bleeding.

• If spinal unsuccessful or unsafe, proceed with GA and use peripheral nerve blocks for analgesia.

He appears very anxious pre-op and asks for 'strong sedation'. How do you approach sedation with spinal anaesthesia, and how do you address his concerns?

• Sedation must be balanced: adequate anxiolysis while preserving airway reflexes and ability to communicate.

• I would:

  • Provide reassurance and explanation of procedure

  • Use low-dose titrated midazolam (0.5–1 mg IV), or small-dose propofol infusion if available and appropriate

  • Monitor level of consciousness closely (verbal responsiveness, oxygenation)

• Avoid oversedation—risk of respiratory depression and unrecognised high block.

During surgery, he develops hypotension with a BP of 80/40. Walk me through your stepwise management and rationale.

• First assess volume status and heart rate:

  • If bradycardic, use ephedrine 5–10 mg IV or atropine 600 mcg

  • If HR is adequate or high, use phenylephrine 50–100 mcg IV

• Give fluid bolus (250–500 mL crystalloid)

• Reposition: Trendelenburg or leg elevation

• Consider vasopressor infusion if persistent hypotension

• Check block height and look for signs of high spinal (respiratory compromise)

• Reassess frequently; document interventions

In PACU, he reports a new left foot drop. What are your immediate priorities, and how would you distinguish likely causes?

• Urgent neuro exam to assess:

  • Motor/sensory distribution (dermatomal vs peripheral)

  • Timing of onset and progression

  • Signs of cauda equina or conus medullaris syndrome

• Causes:

  • Surgical: peroneal nerve compression (e.g., lithotomy stirrups, tourniquet)

  • Anaesthetic: compressive lesion (epidural haematoma, abscess) or nerve trauma

• Investigations:

  • MRI spine ASAP to exclude compressive pathology

  • Nerve conduction studies later if needed

• Escalate to neurosurgery and document timeline thoroughly

Ten minutes after the spinal block, the patient becomes anxious, complains of breathlessness, and cannot move his arms. Please outline your assessment and management of this event.

• Clinical Concern: High spinal block or total spinal

• Immediate Actions:

  • Call for help

  • Apply 100% oxygen by facemask

  • Assess airway patency and prepare for intubation

  • Monitor HR and BP; secure additional IV access

• Management:

  • Intubate if apnoeic or cannot protect airway

  • Use vasopressors (phenylephrine, ephedrine) to manage hypotension

  • Treat bradycardia with atropine or glycopyrrolate

• Monitoring and Support:

  • Continuous ECG, NIBP, SpO2, EtCO2

  • Assess sensory level and reassess frequently

  • Prepare for conversion to GA

He becomes unresponsive and apnoeic. Walk me through your RSI approach in this context.

• Confirm lack of spontaneous breathing and unresponsiveness

• Bag-mask ventilation with 100% O2 while preparing drugs

• RSI:

  • Induction with propofol +/- fentanyl, consider etomidate if hypotensive

  • Rocuronium 1.2 mg/kg for paralysis

• Intubate with appropriate monitoring

• Maintain anaesthesia via TIVA or volatile agent

What factors increase the risk of a high spinal block, and how would you prevent it in future?

• Excessive dose/volume of local anaesthetic (e.g., >3 mL hyperbaric bupivacaine)

• Small patient habitus

• Cephalad positioning post-injection (Trendelenburg)

• Use of adjuvants (opioids increase cephalad spread)

• Prevention:

  • Titrate dose appropriately to patient size and anatomy

  • Avoid steep head-down tilt

  • Monitor closely after injecti

The surgical team wants to proceed urgently. Under what conditions would you allow the surgery to continue?

• Only if patient is stable under GA with airway secured and haemodynamics managed

• Ensure appropriate depth of anaesthesia, monitoring, and support

• Document consent issues and provide detailed post-op explanation

• If unstable or unclear cause of deterioration—abort and reschedule

The patient returns the next morning with persistent weakness and numbness in his left leg. Please describe your assessment and management of this complication.

• Immediate Priorities:

  • Determine nature (motor vs sensory), onset (immediate vs delayed), and distribution (dermatomal vs peripheral)

  • Rule out red flag signs: incontinence, saddle anaesthesia, bilateral symptoms

• Assessment:

  • Full neurological exam of lower limbs

  • Inspect for signs of external nerve injury (e.g., pressure areas)

  • Check spinal site for bruising/swelling/infection

• Investigations:

  • MRI of lumbar spine to rule out haematoma, abscess, ischaemia

  • If peripheral signs: consider nerve conduction studies

• Management:

  • Escalate to neurology/neurosurgery immediately if MRI abnormal

  • Initiate early physio and supportive care if non-compressive neuropathy

  • Comprehensive documentation, incident reporting, and open disclosure

How would you determine if the injury is anaesthetic or surgical in origin?

• Anaesthetic injury more likely if:

  • Dermatomal pattern

  • Immediate onset post-block

  • MRI shows spinal pathology

• Surgical injury more likely if:

  • Peripheral distribution (e.g., common peroneal)

  • Associated with tourniquet, stirrup, or positioning

  • Onset after surgery, no central signs

What are the medicolegal steps you must take in this situation?

• Document timing, findings, and all steps taken

• Notify senior anaesthetist and department lead

• Discuss findings openly with patient/family (open disclosure)

• File incident report and follow local protocol

• Ensure follow-up and continuity of care