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Regional V/Q changes in asthmatics after histamine inhalation.
European Journal of Respiratory Diseases. Supplement
|January 1, 1986
Summary
Histamine inhalation in asthma causes patchy ventilation changes but no blood flow alterations, significantly reducing peak expiratory flow. These histamine-induced asthma defects differ from other asthma triggers and are improved by terbutaline.
Area of Science:
- Pulmonary Medicine
- Respiratory Physiology
- Medical Imaging
Background:
- Asthma is a chronic respiratory disease characterized by airway inflammation and bronchoconstriction.
- Understanding the immediate physiological changes during asthma exacerbations is crucial for effective management.
- Histamine is a potent bronchoconstrictor that can trigger asthma symptoms.
Purpose of the Study:
- To investigate the immediate effects of histamine inhalation on regional ventilation and pulmonary blood flow in adults with perennial asthma.
- To compare ventilation-perfusion changes in histamine-induced asthma (HIA) with other asthma triggers and spontaneous attacks.
- To evaluate the therapeutic and prophylactic effects of terbutaline in HIA.
Main Methods:
- Utilized gammacamera imaging with 81mKr for ventilation and 99mTc-labeled particles for blood flow in seventeen asthma patients and two controls.
- Administered histamine inhalation challenge to induce asthma (HIA).
- Monitored simultaneous changes in peak expiratory flow (PEF) alongside imaging studies.
Main Results:
- Histamine inhalation induced patchy ventilation defects in asthmatic patients but did not alter pulmonary blood flow distribution.
- Peak expiratory flow (PEF) was significantly reduced following histamine challenge.
- Ventilatory changes in HIA were not stereotypic, varied between challenges, and differed from exercise-, antigen-, or spontaneous asthma-induced defects.
- Terbutaline demonstrated therapeutic and prophylactic benefits against histamine challenge.
Conclusions:
- Histamine-induced asthma primarily affects ventilation distribution, not pulmonary blood flow, immediately after challenge.
- The pattern of ventilation defects in HIA is distinct from other asthma triggers, suggesting specific pathophysiological mechanisms.
- Terbutaline is effective in mitigating the immediate respiratory effects of histamine-induced bronchoconstriction in asthma patients.