Emergency management of anaphylaxis (Table 14.14)
| Emergency management of anaphylaxis (Table 14.14) |
| 1 | Stop administration of any precipitant, assess severity of reaction (see Table 14.13) and treat accordingly. Call for assistance. Give intramuscular adrenaline (adult or child): adrenaline 0.01 mg/kg up to a maximum of 0.5 mg (= 0.5 mL of 1:1000 solution) IM (lateral thigh). Establish IV access. Lie patient flat. Give high flow oxygen, airway/ventilation support if needed. If hypotensive, establish additional wide bore access (ie 14G or 16G in adults) for normal saline infusion. Use: sodium chloride 0.9% solution 20 mL/kg IV bolus, over 1 to 2 minutes under pressure. |
| 2 | If there is an inadequate response, an immediate threat to life or deterioration: Start an IV adrenaline infusion, see Table 14.15 OR Repeat IM adrenaline every 3 to 5 minutes as determined by BP and bronchospasm. Consider also: For hypotension, repeat normal saline boluses: sodium chloride 0.9% solution 10 to 20 mL/kg IV bolus, up to total of 50 mL/kg over the first 30 minutes. treat severe bradycardia if present: vasopressin 10 to 40 units IV OR metaraminol 2 to 10 mg IV. for anaphylactic cardiac arrest, rapid escalation to high-dose adrenaline (3 to 5 mg IV every 2 to 3 minutes in adults) may be effective. if beta blocked or in heart failure (adults), consider glucagon/phosphodiesterase inhibitors/balloon pump, eg: glucagon 1 to 5 mg IV loading dose over 5 minutes, followed by 5 to 15 micrograms/minute. For bronchospasm, continuous salbutamol nebulisers (5 mg by nebuliser driven by oxygen at least 8 L/minute), or continuous actuations of metered dose inhaler into ventilation circuit if intubated corticosteroids: hydrocortisone 5 mg/kg IV 6 hourly FOLLOWED BY prednis(ol)one 1 mg/kg up to a maximum of 50 mg orally daily for 4 days. For upper airway obstruction, nebulised adrenaline may provide some relief, use: adrenaline 5 mg in 5 mL (= 5 mL of 1:1000 solution) via nebuliser prepare for surgical airway. |
| 3 | Observe for an adequate period and arrange appropriate follow-up. Inpatient care After the resolution of all symptoms and signs, observe for a minimum of 4 hours after the last dose of adrenaline or until daylight hours. Children or adults with a likelihood of biphasic reaction should be admitted for at least 12 hours. Take blood for mast cell tryptase on arrival, 1 hour after arrival, and prior to discharge. Admit longer (overnight) those with severe reactions, a history of life-threatening reactions or poorly controlled asthma, and those who present late in the evening. Prior to discharge Discuss allergen avoidance measures (including wearable personal medical identification, eg MedicAlert). Ensure that an alert is placed in hospital/practice records/computer system. Ensure that referral letter/summary contains a detailed record of reaction features and timing, possible precipitants and times of exposure. Outpatient follow-upFollow-up by a specialist allergist is recommended for all those with moderate to severe reactions, and with mild reactions to food if the patient also has asthma. If there is significant risk of re-exposure prior to allergist follow-up: Arrange for an EpiPen [NB4]. Demonstrate correct use with an EpiPen trainer. Provide a written action plan (www.allergy.org.au). |
| NB1: If required in a child, minimum total dose should be atropine 0.1 mg IV, as lower doses have been reported to cause paradoxical bradycardia in children. NB2: In children, hypotensive anaphylaxis is very rare with inadequate experience to provide dosage recommendations. NB3: It is important to note that in anaphylaxis the BP is not just low, but may be unrecordable. Therefore doses of vasoconstrictors are much higher than those used in other clinical situations where hypotension may imply a BP of 90 mm Hg or less. NB4: EpiPen is the Australian trade name of a pre-loaded auto-injector pen containing adrenaline 300 micrograms in 0.3 mL. EpiPen Jr contains adrenaline 150 micrograms in 0.3 mL. Adapted with permission from Brown SG. Anaphylaxis: clinical concepts and research priorities. Emergency Medicine Australasia 2006; 18(2):155-69. Copyright © 2006 Wiley-Blackwell Publishing Ltd. | |
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