Why We Do What We Do: HELIOX

A young child comes to the ED with diffuse wheezing and retractions. You diagnose the patient with RSV bronchiolitis. The child’s oxygen saturation is in the low 90’s and is working very hard to breath. You have tried albuterol but the patient’s symptoms aren’t getting much better. You are concerned you might have intubate this patient if you do not find another solution quickly. Check out the article attached and the thoughts below to offer a possible solution.

Noninvasive ventilation with helium-oxygen in children – J of Critical Care 2012

HELIOX is a combination of both Oxygen and Helium. Helium being an inert gas with a low molecular weight has a low density (7x less density). Nitrogen on the other hand has a higher molecular weight and higher density. By replacing nitrogen with helium we are effectively decreasing the amount of work it takes to move air as we have reduced the resistance to flow. Further HELIOX allows for better CO2 diffusion at a rate “4-5 times faster than in air-oxygen mixture”.

HELIOX has been shown to be very effective in treating COPD in the adult literature. The article suggests that it is also effective in the pediatric populations, especially in obstructive pathology including: croup, bronchiolitis, status asthmaticus, angioedema, post extubation subglottic edema, etc. It is recommended that a nonrebreather mask be used at flows of 10-15mL/min. Nebulizing medicines at 10-12mL/min using Heliox is also an effective technique for delivery. In combination with NIV (noninvasive ventilation) Heliox may obviate the need for intubation. Due to its low density and ease of flow, “HELIOX can decrease the pressure gradient required to maintain a given flow, less pressure can be used to obtain the target tidal volumes, which, in turn, diminishes peak pressures and minimizes the risk of barotrauma and volutrauma.”

So why aren’t we using this gas on everybody? It does have some pitfalls. There is some anecdotal evidence that it may cause hypoxia secondary to atelectasis. The authors suggest we use CPAP to address this issue as it will stent the aveoli open. Due its thermal conductive properties, prolonged HELIOX administration at 36 degrees celcius may cause for hypothermia in neonates and small infants. So try to warm the gas if you can. HELIOX is also relatively expensive when compared to other therapeautic gases (oxygen) and requires special modifications to ventilator devices to accommodate its use.

That being said….if you have HELIOX available and a nonrebreather or nebulizer it may be a solution that prevents you from having to intubate a child who is not looking like a peach.

Reference:
Martinon-Torres MD, Phd, F “Noninvasive ventilation with helium-oxygen in children” J of Critical Care (2012) 27, 220e1-220e9.

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