Algorithm
The
Algorithm
In an anaphylaxis/asthma patient
unconscious
requiring
bag valve mask support
A - Adrenaline
1mcg/kg intravenously push dose every 2-3 minutes until infusion commences at 0.5mcg/kg/min (titrate up/down). Use cardiac arrest dose if indicated.
M - Muscle Relaxant
First and only attempt at laryngoscopy must be best attempt
A - Airway - ETT
With working cuff to successfully oxygenate with high airway pressures. Mask and LMA unsuitable
X - oXygenate
Xtreme obstructive ventilation
- 100% oxygen, Small tidal volumes, High PIPs required, Long expiratory time, high flow rate, no PEEP.
Xtra bronchodilators as required
Xtra vasopressors/volume as required
X PneumothoraX
4 Minutes
Max 4 minutes until definitive airway and oxygenation (oral ETT or FONA) to avoid brain injury
Who should use this
algorithm?
This algorithm applies to all clinicians who are capable of endotracheal intubation or are part of an intubating team including paramedics, doctors, and nurses.
Non intubating clinicians need to understand that it is unknown how long bag valve mask ventilation can oxygenate someone with critical asthma/anaphylaxis or severe airway obstruction before it fails. The most senior person needs to devote every effort to deliver oxygen - a two person technique may help.
The quick summary
The time to hypoxic brain injury is extremely short and cannot be extended by CPR in hypoxic arrest.
Watch the 10 minute section 4 lecture so you can have the vision to achieve definitive care in 4 minutes. ETCO2 confirmation of tube placement is always mandatory, even when you are moving fast to save a life!
Most young people with anaphylaxis die from bronchospasm - especially food allergy which is the most common trigger presenting to ED. Bronchospasm also occurs in drug and venom allergy and causes death in young people. This algorithm covers all bases.
Airway pressures are high - too high for anything other than an ETT. BVM and LMA are unsuitable.
First attempt must be the best attempt followed by a surgical airway
Aspiration risk is high and consequences catastrophic
Intubation is inevitable - why not do it before hypoxic brain injury
Understand the medical adjuncts, risk of obstructive hyperinflation, risk of pneumothorax and how to perform difficult ventilation in the face of high pressures and an obstructive pattern using a laerdal bag post intubation
In 2020, the World Allergy Organisation added acute onset bronchospasm alone (without skin symptoms) after exposure to a likely trigger as part of anaphylaxis diagnostic criteria
Anaphylaxis Definition
(World Allergy Organisation)
Either 1 or 2:
1. Acute onset laryngeal involvement, bronchospasm or hypotension after exposure to a known or highly probable allergans for that patient (minutes to several hours) even in the absence of skin symptoms
2. Acute onset of an illness (minutes to several hours) with simultaneous involvement of skin, mucosal tissue, or both
AND AT LEAST ONE OF THE FOLLOWING
a) Respiratory compromise (dyspnoea, wheeze-bronchospasm, stridor, hypoxemia
b) Reduced BP or associated symptoms of end organ hypoperfusion (eg hypotonia, syncope, incontinence)
c) Severe GI symptoms (eg severe crampy abdominal pain, repetitive vomiting, especially after exposure to non-food allergans.
Reference:
Cardona V, Ansotegui IJ, Ebisawa M, El-Gamal Y, Fernandez Rivas M, Fineman S, Geller M, Gonzalez-Estrada A, Greenberger PA, Sanchez Borges M, Senna G, Sheikh A, Tanno LK, Thong BY, Turner PJ, Worm M. World allergy organization anaphylaxis guidance 2020. World Allergy Organ J. 2020 Oct 30;13(10)