Anaphylaxis

Anaphylaxis Criteria:

(Sensitivity 97%, Specificity 82%, positive predictive value (PPV) 69%,  negative predictive value (NPV) 98%)

1. Illness with acute onset involving skin/mucosa AND one of the following: Respiratory compromise or Hypotension

2. Two of the following after exposure to suspected antigen: Skin involvement, Respiratory compromise, Hypotension, GI complaints

3. Hypotension after exposure to known allergen.

Treatment Algorithm

Critical Treatments:

Immediate intramuscular (IM) adrenaline administration in the anterior thigh.

Adult: 0.3-0.5 mg 1:1000 adrenaline IM q5 min

Children: 0.01 mg/kg q5 min 1:1000 adrenaline IM q5 min

In refractory cases when patients do not respond to two IM doses, proceed to intravenous adrenaline.

Adrenaline infusion:

Adult: 1 mg in 250 mL D5W, 0.25-1 mL/min (1-4 ug/min) up to 2.5 mL/min (10ug/min)

Children: 0.1 ug/kg/min with max of 1.5 ug/kg/min (0.6 x body weight (kg) of epinephrine diluted in 100 mL normal saline (NS) yields 0.1 ug/kg/min if run at 1 mL/hr)

Additional medications:

  • IM Piriton 10mg (H1 antagonist)
  • IV Ranitidine 50mg (H2 antagonist)
  • Dopamine/Dobutamine for refractory shock: 5-20 ug/kg/min- if adrenaline infusion didn’t stabilize the BP.
  • Glucagon (for those on beta-blockers): 1-5 mg IV over 5 minutes, then 5-15 ug/min (20-30 ug/kg up to 1 mg in children)

Hemodynamic instability is secondary to intravascular volume shifts. Volume resuscitation of 2-7 liters should be used in those with persistent hypotension, with NS preferred over Ringer’s Lactate.

Ref:

http://www.emdocs.net/anaphylaxis-go-wrong-can-improve/

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