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Scenario — Anaphylaxis following wasp sting at community fair
Patient Information
Dispatch
You are called to a patient (Margaret Holt, 75YO female) near the garden display stalls at the Kalamunda Community Fair. Bystanders report she was stung by a wasp and is now having difficulty breathing.
Incident History
Pt was browsing the garden display when she was stung on the right forearm by a wasp approximately 5 minutes ago. She immediately developed itching and hives across her arms and chest, and is now reporting throat tightness and difficulty breathing.
Emergency Contact
David Holt (Son) 0412 883 547
Initial Rapid Assessment
Response
Alert
Airway
Patent but patient reports throat tightness. Nil audible stridor at rest. Nil visible angioedema to lips or tongue on initial inspection.
Breathing
Laboured. Audible wheeze bilaterally. Increased work of breathing with accessory muscle use. RR elevated.
Circulation
Radial pulse rapid and weak. Skin flushed across face and chest. Raised urticarial welts visible across both forearms and anterior chest. Wasp sting site visible on right forearm — stinger no longer present.
Disability
GCS 14 (E3V5M6). Alert and anxious. Orientated to time, place and person. Complaining of dizziness.
Exposure
Urticarial rash across forearms and anterior chest. Sting site on right forearm — localised erythema and swelling. No other injuries noted.
Vitals
Time SpO2 Resp Dist RR Pulse BP CRT GCS PERL Temp BGL Pain
Initial 91% (RA) Moderate 24 118 86/60 3s 14 4 4 ++ 37.1 – 6
10 mins 97% (O2 NRB 15L) Mild 18 98 98/64 <2s 15 4 4 ++ 37.1 – 3
History Taking
Signs/Symptoms
Throat tightness, difficulty breathing, audible wheeze, dizziness, widespread itching and hives across arms and chest.
Onset
Approximately 5 minutes prior to EHS arrival, immediately following wasp sting to right forearm.
Pain
Throat tightness and chest tightness rated 6/10. Localised pain and burning at sting site on right forearm.
Quality
Tight, constricting sensation in throat and chest. Burning itch across skin.
Radiates
Nil radiation of pain.
Severity
6/10
Allergies
No known drug allergies. No previously known allergy to wasp or bee stings — first significant reaction.
Medications
Ramipril 5mg daily (for hypertension). Atorvastatin 20mg daily. No antihistamines taken today.
Pertinent History
Known hypertension managed with Ramipril. Otherwise well. No prior history of anaphylaxis or significant allergic reaction. No cardiac history. No asthma.
Last Oral Intake
Ate a sandwich and had a cup of tea approximately 1 hour ago.
Treatment
A bystander removed the wasp stinger from right forearm using a scraping motion approximately 2 minutes ago. No medications administered prior to EHS arrival.
Events Leading
Patient was walking through the garden display stalls at the Kalamunda Community Fair when she was stung on the right forearm by a wasp. She reports symptoms began within 1–2 minutes of the sting.
Scenario Progression and Treatment Objectives

((If the trainee attempts to sit the patient upright in a chair or allows her to stand, inform them that Margaret says she feels very dizzy when she tries to sit up — redirect to supine positioning with legs outstretched.))

((If the EpiPen is not administered within the first 2–3 minutes, Margaret reports that her throat feels tighter and her voice becomes slightly hoarse — increase resp_dist to Severe and drop SpO2 to 87% RA.))

((If oxygen is not applied after EpiPen administration, SpO2 remains at 91% and breathing does not improve at the 10-minute mark.))

((If the trainee considers administering Loratadine instead of or before adrenaline, remind them that antihistamines have no role in the treatment of anaphylaxis — the EpiPen must be administered first.))

((If the trainee does not reassess BP before any additional treatment steps, prompt them: 'What are Margaret's obs telling you about her cardiovascular status?'))

((If the trainee does not monitor Margaret in the supine position post-EpiPen for the minimum one-hour period before mobilisation, ask: 'Is it safe for Margaret to stand up and walk to the FAP now?' — expected answer: No, minimum 1 hour post single dose of adrenaline before mobilisation.))

This patient is suffering from anaphylaxis secondary to a wasp sting, presenting with urticaria, bronchospasm, hypotension, and tachycardia — involvement of respiratory and cardiovascular systems confirms anaphylaxis rather than a mild localised allergic reaction.

  • Ensure scene safety and don appropriate PPE.
  • Perform Primary Survey — identify anaphylaxis (respiratory + cardiovascular involvement + urticaria across two or more body systems).
  • Position Margaret supine with legs outstretched — do NOT allow her to sit upright in a chair or stand.
  • Administer Adrenaline Auto-Injector EpiPen 300 MICROg IM into outer mid-thigh — anaphylaxis.
  • Apply oxygen via Non-Rebreather Mask at 10–15 L/min — target SpO2 94–98%.
  • Conduct Vital Sign Survey — HR, BP, RR, SpO2, GCS, CRT — document pre-intervention baseline.
  • Perform history taking including IMISTAMBO components — confirm no prior allergy history, current medications (note Ramipril use).
  • Monitor patient persistently — reassess vitals every 10 minutes (or 5 minutes if time critical).
  • If wheeze persists after EpiPen and oxygen, consider Salbutamol 4–12 puffs (400–1200 MICROg) via MDI and spacer.
  • Do NOT mobilise patient until minimum 1 hour post single EpiPen dose — assess circulatory stability before any movement.
  • Arrange transport to hospital for monitoring — advise receiving facility patient requires 4 hours observation post last dose of adrenaline due to risk of biphasic reaction.
  • Contact CSPSOC for clinical advice and to advise of anaphylaxis presentation.
  • Document all interventions, timing of EpiPen administration, and patient response on patient care record.
  • Scenario ends on arrival of ambulance and IMISTAMBO handover.
  • Attention to hand hygiene will be given throughout the scenario.

Clinical references: Anaphylaxis · Adrenaline Auto-Injector (EpiPen) · Oxygen · Salbutamol Sulphate (Ventolin) · Adrenaline Autoinjector 'EpiPen' · MDI & Space Chamber