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Updates



17/03/14 - TIMING OF TRYPTASE ASSAY IN ANAPHYLAXIS
There is considerable variation in the literature over the timing of blood collection for Tryptase levels during and after anaphylaxis.

Since the initial publication of The ACM, ANZAAG has released management guidelines for anaphylaxis and included in these are recommendations for timing and management of blood samples.

Although the timing of samples in The ACM are similar, they differed enough for ANZAAG to approach the Author and suggest the following guidelines to maximise the chance of accurate anaphylaxis diagnosis. These guidelines will be incorporated into the next edition of The ACM and in the soon to be released e-book.


ANZAAG includes specialists with an interest in perioperative allergy: anaesthetists, immunologists pathologists and specialist laboratory technicians. The issue of when and how to take tryptase was discussed at length as part of the production of the ANZAAG/ANZCA anaphylaxis managment guidelines. The aim was to optimize the ability to diagnose anaphylaxis while minimizing unnecessary tests and expense. The decision we made was to recommend the following :

• capture the peak of the tryptase rise (1 hour) once the acute crisis has settled
• second level whilst still elevated but showing a normal downward trend (4 hours)
• baseline level to be taken once the acute episode has completely settled to exclude chronic elevation/mastocytosis (>24 hours).

The Post Crisis Management card is available at www.anzaag.com as part of the full anaphylaxis management resource.

The graph below (taken from Schwartz LB. Diagnostic value of tryptase in anaphylaxis and mastocytosis. Immunol Allergy Clin N Am 26 (2006) 451-463) helps to demonstrate why these times were selected.




For completeness we also noted on our guidelines that tryptase is unstable in whole blood. It needs to be sent promptly to the laboratory for processing to avoid false negatives. Particularly if the anaphylaxis occurs out of hours or in remote areas it is worth making people aware of this issue where possible. If the blood cannot be processed immediately it should be refrigerated and processed as soon as possible. Blood can be collected in serum or EDTA tube.


13/03/14 - SALBUTAMOL DOSE FOR SEVERE BRONCHOSPASM
The dose of salbutamol of 100-300mcg/kg/hr was based on that given in the book Emergencies in Anaesthesia by Allman et al. (1)

However, an alternative staged dosing consistent with guidelines from the Royal Melbourne Childrens Hospital and the Starship Hospital in Auckland is:

5-10mcg/kg/min for the first hour, followed by 1-2mcg/kg/min thereafter.

1. Lutman D. Acute Severe Asthma. In: Keith Allman, Andrew McIndoe and Iain Wilson, Emergencies in Anaesthesia, 2nd ed. Oxford, UK. Oxford University Press 2009.


13/12/13 - CORRECTION TO TAB 20: LOCAL ANAESTHETIC SYSTEMIC TOXICITY
'anesthesia' should read 'anaesthesia' in the international edition.


13/12/13 - CORRECTION TO TAB 20: LOCAL ANAESTHETIC SYSTEMIC TOXICITY
On the right hand page of this scenario, the dose of Intralipid 20% should read 1.5 ml/kg not 1.5 mg/kg.