2024.2 Day 2 VIVA 19

Obstetric Anaesthesia

You are called to review a patient with threatened premature labour. She is 28 years old, G2 P1 at 34+5 weeks gestation. She has had a previous vaginal delivery complicated by a postpartum haemorrhage. She has a Body Mass Index (BMI) of 27 (70kg), has no other past medical history, and this pregnancy has been uneventful to date. The midwife reports that she is contracting, and the cardiotocograph (CTG) shows a foetal bradycardia. You immediately attend to the patient with the obstetrician, who diagnoses a cord prolapse.

What is your immediate management of this obstetric patient with a cord prolapse?

Cardiovascular:

  • TIA history: clarify timing (<3 months = higher risk), residual neurological deficits, assess indication for anticoagulation.

  • BP control: review recent BP trends, hold candesartan on DOS to reduce risk of perioperative hypotension.

  • Functional status: assess METs ≥4 (e.g., can walk 400m or climb stairs) to estimate cardiac reserve.

Renal/Diabetes:

  • CKD3 (eGFR 30–60): adjust renally cleared drugs, avoid nephrotoxins (NSAIDs), and closely monitor electrolytes and fluid balance.

  • Metformin: withhold 48h pre-op due to risk of lactic acidosis especially in setting of contrast or hypotension.

Anticoagulation:

  • Rivaroxaban: if CrCl 30–50, stop 48h prior; extend to 72h if <30.

  • No bridging needed: CHA2DS2-VASc = 4 (moderate risk) with no recent thromboembolic events.

Geriatric Risks:

  • Frailty screening: use SARC-F or gait speed (>5s for 4m = frailty).

  • Cognition: use Mini-Cog or 4AT; screen for delirium risk factors (visual/hearing impairment, poor sleep).

Scenarioville Context:

  • No ICU or neurology → careful documentation of pre-op neuro baseline.

  • Limited blood bank → ensure G&S; crossmatch if high bleeding risk anticipated.

Would you request an echocardiogram?

  • Only if clinical suspicion: murmurs, signs of HF, recent decompensation.

  • In Scenarioville: echo may delay surgery and is not always accessible.

  • Rely more heavily on METs assessment and physical exam.

How would you modify if his CrCl was 25ml/min?

  • Withhold rivaroxaban for 72h pre-op to ensure clearance.

  • Review all medications for renal dosing (e.g., reduce dose or stop metformin, gabapentin).

  • Insert catheter to monitor urine output intra/post-op and guide fluid management.

  • Avoid IV contrast; consult nephrology early if planning any imaging.

His daughter mentions he’s been confused lately. Your action?

  • Delay surgery until cognitive baseline is clarified.

  • Rule out causes: UTI, hypoglycaemia, metabolic disturbance.

  • Request collateral history and formal cognitive assessment (e.g. 4AT).

  • If urgent surgery is still needed: increase post-op monitoring and pre-warn nursing for delirium risk.

The surgeon insists on continuing metformin. Your response?

  • Quote ANZCA PS56: metformin should be stopped 48h pre-op.

  • Explain risks: accumulation with impaired renal function → lactic acidosis.

  • Suggest intra-op blood gas monitoring if metformin was taken.

  • Recommend endocrinology input post-op before restarting.

Your spinal fails. Outline your GA plan for TURP in this patient.

Airway Plan:

  • RSI with ketamine 1mg/kg and rocuronium; ketamine maintains haemodynamics.

  • Avoid propofol if hypotension anticipated.

  • ETT over LMA preferred for airway protection during prolonged lithotomy and irrigation.

Maintenance:

  • Sevoflurane with air/O2; desflurane not available.

  • BIS monitoring to titrate depth, especially in elderly.

  • Minimise opioids intra-op; small boluses of fentanyl if required.

TURP-Specific Risks:

  • Irrigation fluid absorption → TURP syndrome.

  • Limit resection to <60min; monitor sodium intra-op.

  • Pre-warn surgical team to report signs of excess bleeding or glycine absorption.

Monitoring:

  • ECG, SpO2, EtCO2, NIBP.

  • Insert arterial line if BP labile or if Na+ needs frequent checking.

The surgeon reports ‘poor visibility’ due to bleeding. Your management?

  • Ensure haemodynamic stability and normothermia (coagulopathy contributor).

  • Check coagulation profile (PT, APTT, platelet count).

  • Administer TXA 1g IV if not yet given.

  • Request surgeon apply traction to catheter balloon for tamponade.

  • Consider shortening resection time and planning staged TURP if bleeding persists.

ETCO₂ suddenly drops to 15mmHg. Differential and actions?

  • Venous air embolism (esp. with open veins during TURP)

  • PE (immobile, AF)

  • Circuit disconnect or massive blood loss

  • Management:

    • 100% O2

    • Check for disconnects, assess SpO₂ and BP

    • Stop surgery, place patient in left lateral decubitus and Trendelenburg if embolism suspected

    • Support circulation with vasopressors

How would you dose rocuronium with his CKD3?

  • Use lower end of dose range (0.6mg/kg IBW).

  • Anticipate prolonged duration due to reduced clearance.

  • Use TOF monitoring at ulnar nerve; aim TOFR >0.9 before extubation.

  • Avoid redosing unless absolutely necessary.

Scenarioville has no desflurane. Alternatives?

  • Sevoflurane: good for elderly, smoother wake-up.

  • Propofol TIVA: only if pumps and monitoring available.

  • Minimise depth to avoid hypotension; supplement with paracetamol/fentanyl.

Post-op, he’s agitated and trying to remove his catheter. How will you manage this?

Differential Diagnosis:

  • Delirium (hyperactive subtype)

  • Glycine toxicity (TURP syndrome)

  • Pain/discomfort

  • Hypoxia, hypoglycaemia, urinary retention despite catheter

Assessment:

  • Check vitals: SpO₂, BP, HR

  • Check bloods: Na+, glucose, ABG

  • Examine for signs of pain or blocked catheter

  • Review medication chart: opioids/benzos?

Management:

  • Reorient, ensure sensory aids in place

  • Quiet room with natural lighting

  • Haloperidol 0.5mg IV if risk to self or others

  • Avoid sedating drugs if possible

Scenarioville Notes:

  • No geriatrics: ensure documentation and GP follow-up

  • High nurse workload: place near nursing station for observation

His Na+ is 118mmol/L. What now?

  • TURP syndrome confirmed → administer 3% saline 100mL over 20min

  • Restrict free water; avoid hypotonic fluids

  • Monitor Na+ every 1–2 hours

  • Consider ICU transfer if worsening or symptomatic (confusion, seizures)

The nurse asks if this is dementia. How do you respond?

  • Acute change suggests delirium

  • Dementia is chronic, slow onset

  • Reassess when medically optimised

  • Document confusion for GP follow-up

When can he restart rivaroxaban?

  • Resume 24h post-op if no active bleeding

  • Delay 48–72h if ongoing haematuria or high surgical concern

  • Ensure patient is eating and eGFR stable before restarting

His daughter demands discharge.

  • Not safe until:

    • Cognition stable

    • Mobilising safely

    • Pain controlled on PO meds

    • No bleeding

    • Supervision at home confirmed

  • Explain risks: delayed bleeding, falls, unrecognised delirium

Critical Phrases:

  • "Delirium is an acute, fluctuating condition – not dementia."

  • "In the absence of ICU, early recognition and escalation is key."

  • "Rivaroxaban restart depends on bleeding risk, renal function, and oral intake."

  • "TURP syndrome is a clinical diagnosis supported by hyponatraemia."

  • "Safe discharge must include cognitive and functional readiness."

Scenarioville-Specific Risks:

  • No ICU → plan escalation early

  • Limited staff → recovery planning essential

  • No geriatrics → discharge summaries must cover cognitive issues

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