# 199 Some can wheeze, and some can't
Asthma can have a range of presentations; it can also fail to respond to initial treatments. The sick, tired, asthmatic who is fatiguing, or whose chest is "quiet" with little to no audible respirations upon auscultation will soon die.
Assuming all usual initial measures have been underway; that precipitants such as pulmonary infection or allergic stimuli have been sought; and that potential deceivers such as an aspirated foreign body have been eliminated; what to do next?
If the patient is "working" yet maintaining a reasonable oxygen saturation, and the goal is to lessen the "work," if HeliOx (Helium-Oxygen mixture,80%|/20% at low altitudes, 70%|30% at higher altitudes) is available to you, the less viscous gas mixture will have more laminar flow in tight spaces can do much to ease the work of breathing for the patient. A few extra liters of oxygen by nasal cannula may be needed if saturations are borderline, but more oxygen makes the mixture less 'slippery.' This may allow rest and more time for therapies to work.
If the patient is likely to need intubation, but needs optimization first, a DSI Delayed Sequence Intubation, is useful. Ketamine is used to decrease agitation (stop pulling away the oxygen mask) to facilitate use of NIPPV to stabilize the pulmonary status and deliver inhaled meds; the goal is to optimize for intubation, but preferably allow the patient to 'ride out' the episode without intubation. Ketamine is a good choice as it has additional bronchodilator effect as it stimulates native catecholamine release (if not already catecholamine depleted). It does increase RR and BP about 20%. It can have a myocardial depressant effect if catecholamines are depleted. It is generally considered protective of airway reflexes. Consult your local directives.
Beware of a hyperinflated chest due to breath-stacking; rising pressures and lack of chest movement should cause you to immediately open the breathing circuit to vent the excess, you may need to squeeze the chest externally to force air out before resuming. Unwatched for, and un-rescued, barotrauma ensues as in an over-inflated balloon.
Parenteral β-agonists (Terbutaline) and α-β agonists (Epinephrine), once a mainstay of treatment before effective inhaled agents, may have a role in the very-tight 'silent chest' situation where it is presumed that inhaled agents 'can't get in' because the lower airways are locked-down. There is little downside in the critical situation to their use. IM is preferred, subcutaneous is avoided (↓absorption), IV and infusions may be necessary.
When intubated, treatment remains active; the patient must be sedated and paralyzed; and lung-protective strategies used. "Plastic between the cords doesn't cure the disease."
Kim, Eden, DO MPH PGY3. Epinephrine/Terbutaline in Acute Asthma Exacerbation. The Original Kings of County Blog. March 12, 2017.
"basile" Staten Island Corner: The Intubated Asthmatic. The Original Kings of County Blog. September 17, 2012.
Morgenstern, Justin. First10EM Classic: Management of Severe Asthma. CanadiEM. April 1, 2016.
Strayer, Reuben. When the patient can't breathe, and you can't think: The emergency department life-threatening asthma flowsheet. EMUpdates.com. December 1 4, 2011.
Strayer, Reuben. When RSI isn't the Right SI. EMUpdates.com. April 22, 2014.
Neill, Andy. The 3MG Trial. emergency medicine IRELAND. June 16, 2013.
Neill, Andy. The Crashing Asthmatic. emergency medicine IRELAND. May 17, 2013. Video and References.
Global Initiative for Asthma – New 2017 Report and materials.
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