CIMIT Summer Education Series 2009: Frontiers of Inhalation Technologies in Biomedical Sciences and Clinical Medicine

7.14.2009 Treatment of Respiratory Diseases: Inhalation Technology for Obstructive Lung Disease SPEAKER: Sabine Häussermann, PhD: Air Liquide MODERATOR: Dean Hess, PhD: HMS, MGH

Forum Summary

Inhalation technology often involves the inhalation of aerosolized drug particles, but it can also involve the inhalation of gases.  Delivering the correct amount of a drug or gas is always a challenge because the delivered dose depends on the patient’s breathing in addition to the device being used.  Keeping this difficulty in mind, doctors are investigating the usefulness of treating obstructive lung disease with mixtures of helium and oxygen.

Helium is an inert gas with lower density and higher viscosity than air.  Because of its low density, helium is easier to breathe than air, and it is hypothesized that inhaling helium mixed with oxygen might benefit patients with obstructive lung disease by reducing the workload of breathing.  Mixtures of helium and oxygen are safe to inhale because helium is inert and insoluble. 

A number of clinical studies of helium/oxygen mixtures have been completed, and the results are mixed.  It seems that the mask used to deliver the mixture has a large impact on the treatment’s effectiveness.  Masks designed to deliver oxygen alone are often poorly suited for delivering mixtures containing helium. 

Some studies suggest that inhaling a mixture of helium and oxygen is an effective therapy for patients with asthma suffering from severe airway obstruction.  For asthmatics with mild airway obstruction, on the other hand, inhaling a helium/oxygen mixture seems to produce no benefit.  For patients with chronic obstructive pulmonary disease (COPD), inhaling a helium/oxygen mixture only seems to help if the patient is attempting to exercise.  Taken together, these findings suggest that effectiveness of helium/oxygen mixtures is dependent on the state of the disease being treated.

In the future, it is possible that helium/oxygen mixtures could be used to deliver aerosolized drug particles.  One study found that helium/oxygen mixtures increase the penetration of aerosolized drug particles by twenty percent.   

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