The elderly hip fracture — fascia iliaca block and LAST rescue

(a) Justification and the apixaban question (3 marks).

• Justify the block. The displaced femoral-neck fracture causes severe pain on any movement, and the standard ladder (paracetamol, then opioid) has failed — she still rates her pain 8 over 10 after 5 mg of intravenous morphine. Further opioid risks the respiratory depression, the hypotension and, critically in the elderly, the delirium. The Cochrane review and the ED randomised trials confirm that a fascia iliaca block gives 8 to 12 hours of opioid-sparing analgesia, reduces the opioid consumption (with a possible but unproven delirium benefit — Cochrane acute confusional state RR 0.69, CI 0.38 to 1.27, very low quality), and it preserves the airway, the ventilation and the consciousness — the safest analgesic modality for this patient.^[1][2][3]
• The apixaban consideration. Apixaban is a relative concern for any deep nerve block because a haematoma in a closed fascial compartment can cause a compartment syndrome, and the femoral nerve lies close to a vascular sheath. The fascia iliaca block, however, is a plane block deposited superficial to the neurovascular bundle, and the ultrasound-guided approach allows a clear view of the needle tip and the spread, minimising the vascular injury risk. With the last apixaban dose 14 hours ago and a plane (rather than a perineural) technique under ultrasound, the benefit-to-risk balance favours the block — but the operator must be ultrasound-guided, the tip visualised at all times, and the patient counselled on the small bleeding risk.^[3]

(b) The ultrasound-guided fascia iliaca block (7 marks).

• Calculate the dose aloud. Choose ropivacaine 0.5 per cent for its lower cardiotoxicity than bupivacaine in this frail, elderly patient. Ropivacaine plain: 3 mg/kg. For 55 kg: 3 times 55 equals 165 mg maximum. Ropivacaine 0.5 per cent is 5 mg per mL, so the maximum safe volume is 165 divided by 5, which is 33 mL. A 20 mL block (100 mg) sits comfortably within the ceiling with a margin for re-injection if needed. State the dose, the volume and the margin aloud before drawing up.^[4][5]
• Consent, position, prep. Explain the procedure, the agent and the risks (infection, bleeding, nerve injury, LAST, motor block and falls). Position supine with the leg slightly abducted. Full monitoring (ECG, pulse oximetry, blood pressure) and resuscitation equipment including a lipid emulsion 20 per cent ampoule within reach. Sterile skin preparation and a sterile probe cover.
• Ultrasound landmarks. Place the high-frequency linear probe transversely over the inguinal region, sliding from medial to lateral. Identify the femoral artery (pulsatile, non-compressible), the femoral nerve (triangular, hyperechoic, lateral to the artery, outside the fascia iliaca), the fascia lata (the bright superficial line over the thigh muscles) and the fascia iliaca (the deeper bright line over the iliacus muscle). The target plane is deep to the fascia iliaca, over the iliacus, lateral to the artery.
• Needle insertion. Use an in-plane approach from lateral to medial, advancing a 21-gauge block needle under continuous vision. Identify two fascial layers and watch the needle tip pierce the fascia iliaca. Aspirate before every aliquot.
• Inject and confirm. Deposit 20 mL of ropivacaine 0.5 per cent in small aliquots, watching the hypoechoic spread lift the fascia iliaca off the iliacus and track medially beneath the femoral nerve — the ultrasound confirmation of a successful fascia iliaca spread. Stop at any pain, paraesthesia or resistance (intraneural injection).
• Onset and document. Wait 5 to 10 minutes for the onset; test the anterior thigh and the femoral distribution. Document the agent, the concentration, the volume, the milligrams, the ultrasound view, the aspiration check and the block success. Plan a falls-prevention strategy — the quadriceps motor block makes unaided mobilisation unsafe.

(c) The LAST management (5 marks).

• Recognise. This is local anaesthetic systemic toxicity (LAST) in the delayed form — the prodrome of agitation, metallic taste and circumoral tingling, the progression to a generalised tonic-clonic seizure, and the cardiovascular collapse with a broad-complex tachycardia and hypotension, twenty minutes after a large-volume block. The broad QRS is the cardiac sodium-channel blockade, and bupivacaine or ropivacaine in this pattern is LAST until proven otherwise.^[4][5]
• Stop and call. Stop any further local anaesthetic injection (none here, but verify). Call for help and call for the lipid emulsion 20 per cent pack.
• Airway and seizure. Secure the airway with 100 per cent oxygen and a bag-valve-mask; give a benzodiazepine (midazolam 2 to 5 mg intravenously, or lorazepam 4 mg) to control the seizure — do not use propofol or lidocaine for the arrhythmia (piling local anaesthetic or a myocardial depressant onto the arrest).
• Lipid emulsion 20 per cent — the definitive treatment. Give 1.5 mL/kg bolus (about 80 mL in a 55 kg patient) intravenously over 2 to 3 minutes, then start the infusion at 0.25 mL/kg/min (about 14 mL/min). If the arrest is refractory, repeat the bolus and increase the infusion to 0.5 mL/kg/min, to a maximum cumulative dose of about 12 mL/kg over the first 30 minutes. Ropivacaine LAST is more reversible than bupivacaine, but the lipid is given on the same protocol.^[4]
• Cardiovascular support and prolonged CPR. Continue standard ALS in parallel, but anticipate that the arrhythmia may be refractory to standard ALS — the lipid is the decisive agent, and prolonged CPR (the lipid takes minutes to work) may be required. Use amiodarone 300 mg for the ventricular arrhythmia if needed, not lidocaine. Reduce the individual epinephrine doses (smaller aliquots are favoured in LAST — vasopressin is avoided).
• Post-event. Admit to a higher level of care and observe for at least 12 hours, because the recurrence of LAST is described as the lipid infusion is weaned.