Abstract
Heliox is a blend of helium and oxygen with a gas density less than that of air that decreases airway resistance (Raw) in patients ventilated for status asthmaticus. We tested whether breathing an 80:20 mixture of helium:oxygen would reduce pulsus paradoxus (PP) and increase peak expiratory flow (PEF) in patients presenting to the emergency room with an exacerbation of asthma. After receiving 30 min of β-agonist aerosols and intravenously administered methylprednisolone, 27 patients whose PP remained greater than 15 mm Hg and whose PEF remained less than 250 L/min consented to breathe heliox or room air for 15 min. PP decreased and PEF increased with time in control patients, indicating a time-related effect of routine bronchodilator therapy (p < 0.05). PP decreased in 15 of 16 patients during heliox, and the change with heliox was significantly greater than that during air breathing (p < 0.01). PEF measured with a Wright's peak flow meter calibrated for heliox increased in all patients breathing heliox. Again, the increase in PEF during heliox breathing was significantly greater than the corresponding change in control patients breathing air (p < 0.001). To the extent that PP reflects the inspiratory fall in pleural pressure, this reduction in PP indicates a substantial reduction in inspiratory Raw when the less dense gas is inspired through narrowed bronchi having turbulent flow regimes. The 35% increase in PEF while breathing heliox signals a similar reduction in expiratory Raw, which might diminish the hyperinflation often observed during an exacerbation of asthma. Taken together, these effects of heliox are likely to diminish the tendency to inspiratory muscle fatigue until bronchodilation is affected during initial treatment of severe asthma.
| Original language | English |
|---|---|
| Pages (from-to) | 310-314 |
| Number of pages | 5 |
| Journal | American Journal of Respiratory and Critical Care Medicine |
| Volume | 151 |
| Issue number | 2 I |
| State | Published - Feb 1 1995 |
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ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
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Heliox improves pulsus paradoxus and peak expiratory flow in nonintubated patients with severe asthma. / Manthous, Constantine A.; Hall, Jesse B.; Melmed, Ari; Caputo, Mark A.; Walter, James; Klocksieben, James M.; Schmidt, Gregory A.; Wood, Lawrence D H.
In: American Journal of Respiratory and Critical Care Medicine, Vol. 151, No. 2 I, 01.02.1995, p. 310-314.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Heliox improves pulsus paradoxus and peak expiratory flow in nonintubated patients with severe asthma
AU - Manthous, Constantine A.
AU - Hall, Jesse B.
AU - Melmed, Ari
AU - Caputo, Mark A.
AU - Walter, James
AU - Klocksieben, James M.
AU - Schmidt, Gregory A.
AU - Wood, Lawrence D H
PY - 1995/2/1
Y1 - 1995/2/1
N2 - Heliox is a blend of helium and oxygen with a gas density less than that of air that decreases airway resistance (Raw) in patients ventilated for status asthmaticus. We tested whether breathing an 80:20 mixture of helium:oxygen would reduce pulsus paradoxus (PP) and increase peak expiratory flow (PEF) in patients presenting to the emergency room with an exacerbation of asthma. After receiving 30 min of β-agonist aerosols and intravenously administered methylprednisolone, 27 patients whose PP remained greater than 15 mm Hg and whose PEF remained less than 250 L/min consented to breathe heliox or room air for 15 min. PP decreased and PEF increased with time in control patients, indicating a time-related effect of routine bronchodilator therapy (p < 0.05). PP decreased in 15 of 16 patients during heliox, and the change with heliox was significantly greater than that during air breathing (p < 0.01). PEF measured with a Wright's peak flow meter calibrated for heliox increased in all patients breathing heliox. Again, the increase in PEF during heliox breathing was significantly greater than the corresponding change in control patients breathing air (p < 0.001). To the extent that PP reflects the inspiratory fall in pleural pressure, this reduction in PP indicates a substantial reduction in inspiratory Raw when the less dense gas is inspired through narrowed bronchi having turbulent flow regimes. The 35% increase in PEF while breathing heliox signals a similar reduction in expiratory Raw, which might diminish the hyperinflation often observed during an exacerbation of asthma. Taken together, these effects of heliox are likely to diminish the tendency to inspiratory muscle fatigue until bronchodilation is affected during initial treatment of severe asthma.
AB - Heliox is a blend of helium and oxygen with a gas density less than that of air that decreases airway resistance (Raw) in patients ventilated for status asthmaticus. We tested whether breathing an 80:20 mixture of helium:oxygen would reduce pulsus paradoxus (PP) and increase peak expiratory flow (PEF) in patients presenting to the emergency room with an exacerbation of asthma. After receiving 30 min of β-agonist aerosols and intravenously administered methylprednisolone, 27 patients whose PP remained greater than 15 mm Hg and whose PEF remained less than 250 L/min consented to breathe heliox or room air for 15 min. PP decreased and PEF increased with time in control patients, indicating a time-related effect of routine bronchodilator therapy (p < 0.05). PP decreased in 15 of 16 patients during heliox, and the change with heliox was significantly greater than that during air breathing (p < 0.01). PEF measured with a Wright's peak flow meter calibrated for heliox increased in all patients breathing heliox. Again, the increase in PEF during heliox breathing was significantly greater than the corresponding change in control patients breathing air (p < 0.001). To the extent that PP reflects the inspiratory fall in pleural pressure, this reduction in PP indicates a substantial reduction in inspiratory Raw when the less dense gas is inspired through narrowed bronchi having turbulent flow regimes. The 35% increase in PEF while breathing heliox signals a similar reduction in expiratory Raw, which might diminish the hyperinflation often observed during an exacerbation of asthma. Taken together, these effects of heliox are likely to diminish the tendency to inspiratory muscle fatigue until bronchodilation is affected during initial treatment of severe asthma.
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M3 - Article
VL - 151
SP - 310
EP - 314
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
SN - 1073-449X
IS - 2 I
ER -