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anaphylaxis

anaphylaxis

brief overview of Mx

early adrenaline as 1st line Rx

  • 1:1000 im 0.01ml/kg to maximum 0.5ml (Adult 0.5ml) im into lateral thigh, repeat after 5min if no improvement
    • do not give s/c as absorption is unreliable
    • do not give iv adrenaline bolus doses unless arrest imminent
  • if hypotensive:
    • elevate legs, lie patient flat, although may need to have head up at 45 deg if short of breath
    • iv fluid boluses of 10-20ml/kg 0.9% saline
  • if upper airway obstruction, consider nebulised adrenaline as for croup (below) in addition to im adrenaline
  • if inadequate response to repeat im adrenaline dose:
    • commence iv adrenaline infusion at 0.05-1.0mcg/kg/min (see adrenaline for infusions)
  • if airway obstruction not settling, consider early intubation and rapid sequence induction (RSI) for emergency intubation
  • if requires 2 or more adrenaline doses or more than 20ml/kg saline, contact ICU

adjunctive Rx

if wheezing
corticosteroids
antihistamines
  • may help pruritus
  • preferably non-sedating second generation antihistamines (H1)
  • avoid promethazine as it is sedating and may cause hypotension

disposition

  • all patients with anaphylaxis should be observed for 6-12 hours or overnight as risk of rebound if either:
    • more than 1 dose of adrenaline needed
    • if iv fluid bolus needed
    • if lives too far from hospital to return ASAP
  • consider ED Short Stay Observation Unit if suitable
  • discharge advice
  • consider EpiPen
    • a GP cannot prescribe an EpiPEN under PBS as they will need to refer to a paediatrician or immunologist which will delay access, or prescribe a non-PBS more expensive script (~$100)
    • an ED doctor CAN prescribe an EpiPEN as follows:
      • contact PBS Authority 1800 888 333 to get an authority number (you will need patient's Medicare number)
        • authority requirement:
          • “Initial sole PBS-subsidised supply for anticipated emergency treatment of acute allergic reactions with anaphylaxis in a patient who has been discharged from hospital or an emergency department after treatment with adrenaline for acute allergic reaction with anaphylaxis.”
      • write the PBS Authority script
      • AND give the patient a ASCIA anaphylaxis action plan available from here
      • AND explain how to use the epiPEN

potential precipitants

patient information sheets

references and other resources

anaphylaxis.txt · Last modified: 2019/03/16 13:53 by wh