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Supramaximal flow in asthmatic patients.
H Sala1, A Fernández, S Guardia
1Posadas Hospital, El Palomar, Buenos Aires, Argentina. drsala@tutopia.com
The European Respiratory Journal
|July 11, 2002
Summary
In asthma, increased airflow limitation correlates with greater "pendelluft" during supramaximal flows (SF). Salbutamol decreased SF, while methacholine increased it, suggesting altered respiratory mechanics in asthmatics.
Area of Science:
- Respiratory Physiology
- Pulmonary Medicine
- Asthma Pathophysiology
Background:
- Supramaximal flows (SF) are linked to flow limitation in healthy individuals.
- Understanding SF mechanisms in asthma is crucial for respiratory management.
- The impact of bronchodilators and constrictors on SF requires investigation.
Purpose of the Study:
- To investigate the correlation between airflow limitation and SF in asthmatic subjects.
- To examine the influence of salbutamol and methacholine on SF in asthma.
- To elucidate the role of "pendelluft" in SF during varying airflow limitation.
Main Methods:
- Protocol A: Measured basal and interrupted maximal expiratory flow/volume curves in 36 asthmatics.
- Calculated maximal flow at 50% forced vital capacity (V'max50) changes (deltaV'max50).
- Protocol B: Assessed deltaV'max50 after salbutamol (33 patients) and methacholine (12 patients).
Main Results:
- A significant negative correlation was found between forced expiratory volume in one second and deltaV'max50.
- SF significantly decreased after salbutamol administration.
- SF significantly increased after methacholine challenge.
Conclusions:
- In asthmatic patients, "pendelluft" participation in SF increases with greater airflow limitation.
- Salbutamol and methacholine administration differentially affect SF, indicating dynamic changes in respiratory mechanics.
- Findings suggest "pendelluft" plays a significant role in the altered flow dynamics observed in asthma.