ADRENALINE USE IN ANAPHYLAXIS

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ADRENALINE USE IN ANAPHYLAXIS
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• Definition of anaphylaxis
• Anaphylaxis is a serious allergic reaction that
  is rapid in onset and may cause death (Sampson
  2006)

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• The aetiology of anaphylaxis
• Foods
• Insect venoms
• Medications
• Anaesthetics
• Natural rubber latex
• (Brown 2001 Brown 2004a Kemp 2002 Lieberman
  2003 Sampson 2005 Simons 2002a Simons 2007a
  Simons 2007b).

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• Anaphylaxis epidemiology - mortality
• Estimates range from 1030 cases per 100,000
  population per year, with approximately 1 in
  4002000 emergency attendees (Peng and Jick,
  2004 Stewart and Ewan, 1996 Yocum et al, 1999
  Klein and Yocum, 1995 Brown et al, 2001).
• True mortality rates are unknown in anaphylaxis
  (Pumphrey, 2000).
• Data from a UK survey of fatal anaphylaxis in
  individuals over 16 years of age reported 20
  deaths per year 10 related to drugs, 5 to insect
  stings and 5 to foods (Pumphrey, 2000).

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• Symptoms of anaphylaxis (Brown 2001 Brown 2004b
  Kemp 2002 Lieberman 2003 Simons 2002b).
• Skin symptoms urticaria, flushing, itching, and
  angioedema (90)
• Respiratory (70) and gastrointestinal (40)
• symptoms
• Hypotension occurs in 10 to 30
• Symptoms often occur within 5 to 30 minutes ?
  several hours(occasionally)

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• Diagnosis of anaphylaxis
• The diagnosis of anaphylaxis is based largely on
  history and physical findings

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• Efficacy of adrenaline treatment
• Adrenaline acts through adrenoreceptors a1, a2,
  ß1, ß2
• Increase in peripheral vascular resistance by
  vasoconstriction.
• Improve blood pressure, counteracting peripheral
  vasodilatation, as well as a reduction in
  angio-oedema.
• Coronary perfusion is increased as blood pressure
  improves.
• Adrenaline-induced bronchodilation counteracts
  the airway smooth muscle contraction and airway
  narrowing seen in anaphylaxis.

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• Treatment of anaphylaxis adrenaline
• Adrenaline treatment route of administration
• Adrenaline is the mainstay of treatment for
  anaphylaxis.
• Adrenaline injected by an auto-injector into the
  anterolateral aspect of the thigh is the gold
  standard of care in the management of acute
  anaphylaxis.
• Intramuscular, subcutaneous or intravenous
  injection, or by inhalation ? choice for first
  time responders is by intramuscular injection
  into the antero-lateral thigh muscle

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• The subcutaneous route can no longer be
  recommended (Simons et al, 1998).
• The average time to maximum plasma adrenaline
  concentration using the intramuscular route was 8
  minutes, compared with 34 minutes using the
  subcutaneous route. The average maximum plasma
  concentration of adrenaline was significantly
  higher using the intramuscular route (Simons et
  al, 2001a).

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• Inhaled adrenaline also cannot be recommended for
  the treatment of anaphylaxis.
• In a study in children, those treated with
  adrenaline inhalers had blood adrenaline levels
  no higher than a control group treated with
  placebos (Simons FER, 2000b).
• Intravenous adrenaline is not indicated in
  first-responder management of acute anaphylaxis,
  although it has a clear role in
  anaesthetic-related anaphylaxis and refractory
  anaphylaxis, especially in cases not responding
  to intramuscular adrenaline.

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• Intravenous adrenaline has been associated with
  fatal cardiac arrythmias and myocardial
  infarction, these cases have been associated with
  too rapid injection, undiluted doses, or
  excessive doses (Fischer, 1995 Pumphrey, 2000
  Brown, 2001 Montanaro and Bardana, 2002).
• To minimise these adverse effects, the use of
  intravenous adrenaline is now recommended at a
  dilution of 110,000 (Project Team of the
  Resuscitation council, UK, 2005).

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• Dose considerations
• Infants and children Adrenaline 0.01 mg/kg (IM)
  repeated every ten minutes .

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When the child is severely ill and there is real
doubt about absorption from the intramuscular
injection site, adrenaline may be given by slow
intravenous injection in a dose of 10 micrograms/
kg over several minutes using a 110,000 dilution
of adrenaline (Project Team of the Resuscitation
Council (UK) revised May 2005)
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• Adults Adrenaline 0.3 to 0.5 mg (IM) repeated
  every ten minutes (North American, Australasian,
  and UK).
• Some older European literature suggests 0.5 to
  1.0 mg as a maximum initial intramuscular dose
  (Alrasbi 2007 Soar 2008)
• When the patient is severely ill and there is
  real doubt about absorption from the
  intramuscular injection site, adrenaline may be
  given by slow intravenous injection in a dose of
  500 micrograms given at a rate of 100 micrograms
  per minute using a 110,000 dilution of
  adrenaline

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• Conclusions and summary
• Anaphylaxis is a severe, life-threatening
  reaction that can affect all age groups.
• The severity of previous reactions does not
  predict the severity of subsequent reactions.
• Intramuscular adrenaline is the first-line
  treatment for anaphylaxis, with intravenous
  adrenaline reserved for unresponsive anaphylaxis
  or circulatory collapse.
• Early use of adrenaline in anaphylaxis is
  associated with improved outcomes.
• There is a clear need to improve the education of
  both patient and physician on the use of, and
  indications for, adrenaline auto-injectors