Stridor Five Minutes Into a First IV Beta-Lactam Dose
At 14:20 on a 24-bed medical ward, a 45-year-old woman with acute pyelonephritis receives her first dose of IV piperacillin–tazobactam. Her allergy record states 'penicillin - rash as a child'. Five minutes into the infusion she reports a strange taste, flushing and itching. Within two minutes she has generalised urticaria, audible inspiratory stridor, a hoarse voice and is visibly frightened. Observations: HR 132, BP 84/48, RR 30, SpO2 89% on room air. She has asthma and takes salbutamol as needed, which she used this morning. There is one other registered nurse on the corridor; the medical emergency team is hospital-based and usually arrives within four minutes. The drug cupboard holds adrenaline 1:1000 ampoules, chlorphenamine, hydrocortisone, salbutamol nebulisers and oxygen. She is sitting upright in a chair.
1. State your first three actions in order, with doses and routes, and explain why antihistamines and steroids are not first-line.
Read the worked answer
This is anaphylaxis with airway compromise (stridor, hoarse voice) and shock. Adrenaline is the only first-line drug.
- Stop the infusion immediately, but leave the cannula in place and do not flush the line - stop further antigen delivery. Note the time and the volume received.
- Call for help by name and pull the emergency bell. Say the word 'anaphylaxis' and ask for the resuscitation trolley and the MET; that word changes the speed of the response.
- Give adrenaline 0.5 mg IM (0.5 mL of 1:1000) into the anterolateral thigh. Repeat at 5 minutes if there is no improvement. The thigh gives faster and more reliable absorption than the deltoid, and the IM route is far safer than IV outside a critical care setting with continuous monitoring.
Why not chlorphenamine or hydrocortisone first: antihistamines do nothing for laryngeal oedema or hypotension, and steroids take hours to act. Giving them first consumes the minutes in which adrenaline prevents intubation or cardiac arrest. They are adjuncts given after adrenaline. Nebulised salbutamol may help bronchospasm but does not treat upper airway oedema or shock.
Note also that the 'rash as a child' label did not predict this: most fatal reactions occur in people with no history of severe reaction, which is why the drug history must be taken seriously rather than dismissed.
2. While waiting for the MET, how will you position, oxygenate, support and monitor her, and how would you divide roles between the two nurses?
Read the worked answer
Positioning: keep her sitting upright - she is stridorous and hypoxic, and lying her flat can worsen airway obstruction. If she becomes profoundly hypotensive or pre-syncopal, lay her flat with legs raised, but only if breathing allows.
Oxygen: high-flow via a non-rebreathe mask at 15 L/min. Do not delay adrenaline to apply oxygen - do them simultaneously if there are two of you.
Circulation: IV crystalloid bolus (for example 500–1000 mL) through the existing cannula with a fresh giving set, for the hypotension.
Monitoring: continuous SpO2 and cardiac trace, blood pressure every 3–5 minutes, respiratory rate, her ability to speak in full sentences, and voice quality. Increasing hoarseness or a quieter airway signals worsening obstruction, not improvement.
Roles: one nurse stays with the patient, manages airway positioning and oxygen and gives the adrenaline; the second draws up a repeat dose, brings the trolley and defibrillator, checks the drug expiry and meets the MET with a handover. Neither leaves the patient alone.
Prepare for deterioration: loss of consciousness, a silent chest or stridor, or profound hypotension is a peri-arrest airway and requires the anaesthetist immediately; a second IM dose at 5 minutes is indicated. IV adrenaline should only be given by staff trained in it, diluted and titrated, with continuous monitoring.
3. What follow-up, documentation and system-level actions are required once she is stabilised?
Read the worked answer
- Observation period: at least 6–12 hours, longer if the reaction was severe, if repeated adrenaline was needed, or because she has asthma - biphasic reactions occur in a minority of patients, usually within the first 12 hours, so many services admit overnight.
- Allergy record: replace 'penicillin - rash as a child' with an unambiguous entry: 'Anaphylaxis (stridor, hypotension, urticaria) to piperacillin–tazobactam on [date]; treated with IM adrenaline 0.5 mg; grade severe.' Record it in the notes, the drug chart, the electronic record and on an alert band, and tell the patient in writing.
- Antibiotic review: flag piperacillin–tazobactam and other penicillins so the team selects an alternative agent with allergy input.
- Referral and plan: allergy/immunology referral, a written emergency plan, and consideration of an adrenaline auto-injector if local policy supports it for severe reactions; teach her to use it.
- Documentation: a timed narrative - drug start, symptom onset, each intervention with dose and time, and the response - plus an incident/medication safety report.
- System question: why was a first IV penicillin given on a general ward to a patient with a documented penicillin allergy? That belongs in the incident review as a medication-reconciliation and challenge issue, framed as learning rather than blame, because the same gap will harm the next patient.